[{"date_created":"2026-01-20T19:33:40Z","publisher":"Wiley","title":"Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D","issue":"2","quality_controlled":"1","year":"2026","language":[{"iso":"eng"}],"keyword":["electrocatalysis","Co3O4","EQCM-D","OER"],"publication":"ChemCatChem","abstract":[{"text":"Cobalt spinel (Co3O4) catalysts are widely studied in scope of the electrocatalytic oxygen evolution reaction (OER), yet the role of interfacial structural transformation under anodic bias remains under debate. Here, we employ an operando approach, combining a fast electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D), electrochemical impedance spectroscopy (EIS), and Raman spectroscopy to investigate interfacial transformations of Co3O4 nanoparticle electrodes in alkaline electrolyte. We identify two distinct regimes during the anodic sweep prior to the macroscopic OER onset. At lower potentials, the catalyst interface remains mechanically rigid while reversibly associating several OH−/H2O species per oxidized cobalt site. At higher potentials, pronounced softening of the interface occurs alongside further uptake of electrolyte species. This indicates amorphization and a ‘swelling process’ beyond simple adsorption. Notably, an electrochemical conditioning treatment can suppress mass and compliance hysteresis without affecting OER activity, suggesting that most incorporated electrolyte species do not participate in the OER. EIS further reveals that OER intermediates form well below the apparent OER onset potential. These results advance our mechanistic understanding of interfacial transformations in cobalt-based OER catalysts and establish EQCM-D as a sensitive operando technique for probing electrocatalyst transformations.","lang":"eng"}],"author":[{"first_name":"Christian","id":"117722","full_name":"Leppin, Christian","last_name":"Leppin"},{"full_name":"Placke‐Yan, Carsten","last_name":"Placke‐Yan","first_name":"Carsten"},{"first_name":"Georg","last_name":"Bendt","full_name":"Bendt, Georg"},{"first_name":"Sheila","full_name":"Hernandez, Sheila","last_name":"Hernandez"},{"first_name":"Kristina","last_name":"Tschulik","full_name":"Tschulik, Kristina"},{"first_name":"Stephan","full_name":"Schulz, Stephan","last_name":"Schulz"},{"full_name":"Linnemann, Julia","id":"116779","last_name":"Linnemann","orcid":"0000-0001-6883-5424","first_name":"Julia"}],"volume":18,"date_updated":"2026-01-20T19:36:51Z","oa":"1","main_file_link":[{"open_access":"1"}],"doi":"10.1002/cctc.202501104","publication_status":"published","publication_identifier":{"issn":["1867-3880","1867-3899"]},"citation":{"mla":"Leppin, Christian, et al. “Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D.” ChemCatChem, vol. 18, no. 2, e01104, Wiley, 2026, doi:10.1002/cctc.202501104.","bibtex":"@article{Leppin_Placke‐Yan_Bendt_Hernandez_Tschulik_Schulz_Linnemann_2026, title={Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D}, volume={18}, DOI={10.1002/cctc.202501104}, number={2e01104}, journal={ChemCatChem}, publisher={Wiley}, author={Leppin, Christian and Placke‐Yan, Carsten and Bendt, Georg and Hernandez, Sheila and Tschulik, Kristina and Schulz, Stephan and Linnemann, Julia}, year={2026} }","short":"C. Leppin, C. Placke‐Yan, G. Bendt, S. Hernandez, K. Tschulik, S. Schulz, J. Linnemann, ChemCatChem 18 (2026).","apa":"Leppin, C., Placke‐Yan, C., Bendt, G., Hernandez, S., Tschulik, K., Schulz, S., & Linnemann, J. (2026). Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D. ChemCatChem, 18(2), Article e01104. https://doi.org/10.1002/cctc.202501104","ama":"Leppin C, Placke‐Yan C, Bendt G, et al. Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D. ChemCatChem. 2026;18(2). doi:10.1002/cctc.202501104","ieee":"C. Leppin et al., “Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D,” ChemCatChem, vol. 18, no. 2, Art. no. e01104, 2026, doi: 10.1002/cctc.202501104.","chicago":"Leppin, Christian, Carsten Placke‐Yan, Georg Bendt, Sheila Hernandez, Kristina Tschulik, Stephan Schulz, and Julia Linnemann. “Interfacial Softening and Electrolyte Uptake in Co3O4 OER Catalysts: Insight from Operando Spectroscopy and Fast EQCM‐D.” ChemCatChem 18, no. 2 (2026). https://doi.org/10.1002/cctc.202501104."},"intvolume":" 18","user_id":"116779","department":[{"_id":"985"}],"_id":"63675","article_number":"e01104","type":"journal_article","status":"public"},{"publication_identifier":{"issn":["2155-5435","2155-5435"]},"publication_status":"published","citation":{"ama":"Scharf CH, Chandraraj A, Dyk K, et al. Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts. ACS Catalysis. Published online 2026. doi:10.1021/acscatal.5c08785","ieee":"C. H. Scharf et al., “Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts,” ACS Catalysis, Art. no. acscatal.5c08785, 2026, doi: 10.1021/acscatal.5c08785.","chicago":"Scharf, Carl Hendric, Alex Chandraraj, Konrad Dyk, Felix Stebner, Sören Lepin, Jing Tian, Laila El Bergmi Byaz, et al. “Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts.” ACS Catalysis, 2026. https://doi.org/10.1021/acscatal.5c08785.","apa":"Scharf, C. H., Chandraraj, A., Dyk, K., Stebner, F., Lepin, S., Tian, J., El Bergmi Byaz, L., Stettner, J., Leppin, C., Kotova, A., Reinke, S., Linnemann, J., Maroun, F., & Magnussen, O. M. (2026). Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts. ACS Catalysis, Article acscatal.5c08785. https://doi.org/10.1021/acscatal.5c08785","short":"C.H. Scharf, A. Chandraraj, K. Dyk, F. Stebner, S. Lepin, J. Tian, L. El Bergmi Byaz, J. Stettner, C. Leppin, A. Kotova, S. Reinke, J. Linnemann, F. Maroun, O.M. Magnussen, ACS Catalysis (2026).","bibtex":"@article{Scharf_Chandraraj_Dyk_Stebner_Lepin_Tian_El Bergmi Byaz_Stettner_Leppin_Kotova_et al._2026, title={Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts}, DOI={10.1021/acscatal.5c08785}, number={acscatal.5c08785}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Scharf, Carl Hendric and Chandraraj, Alex and Dyk, Konrad and Stebner, Felix and Lepin, Sören and Tian, Jing and El Bergmi Byaz, Laila and Stettner, Jochim and Leppin, Christian and Kotova, Anastasiia and et al.}, year={2026} }","mla":"Scharf, Carl Hendric, et al. “Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts.” ACS Catalysis, acscatal.5c08785, American Chemical Society (ACS), 2026, doi:10.1021/acscatal.5c08785."},"author":[{"first_name":"Carl Hendric","full_name":"Scharf, Carl Hendric","last_name":"Scharf"},{"full_name":"Chandraraj, Alex","last_name":"Chandraraj","first_name":"Alex"},{"first_name":"Konrad","last_name":"Dyk","full_name":"Dyk, Konrad"},{"full_name":"Stebner, Felix","last_name":"Stebner","first_name":"Felix"},{"last_name":"Lepin","full_name":"Lepin, Sören","first_name":"Sören"},{"full_name":"Tian, Jing","last_name":"Tian","first_name":"Jing"},{"full_name":"El Bergmi Byaz, Laila","last_name":"El Bergmi Byaz","first_name":"Laila"},{"full_name":"Stettner, Jochim","last_name":"Stettner","first_name":"Jochim"},{"first_name":"Christian","full_name":"Leppin, Christian","id":"117722","last_name":"Leppin"},{"full_name":"Kotova, Anastasiia","last_name":"Kotova","first_name":"Anastasiia"},{"first_name":"Sebastian","last_name":"Reinke","full_name":"Reinke, Sebastian","id":"117727"},{"first_name":"Julia","orcid":"0000-0001-6883-5424","last_name":"Linnemann","id":"116779","full_name":"Linnemann, Julia"},{"first_name":"Fouad","full_name":"Maroun, Fouad","last_name":"Maroun"},{"last_name":"Magnussen","full_name":"Magnussen, Olaf M.","first_name":"Olaf M."}],"oa":"1","date_updated":"2026-02-16T14:25:00Z","doi":"10.1021/acscatal.5c08785","main_file_link":[{"open_access":"1","url":"https://pubs.acs.org/doi/10.1021/acscatal.5c08785"}],"type":"journal_article","status":"public","department":[{"_id":"985"}],"user_id":"116779","_id":"64182","article_type":"original","article_number":"acscatal.5c08785","quality_controlled":"1","year":"2026","date_created":"2026-02-16T14:22:15Z","publisher":"American Chemical Society (ACS)","title":"Role of Defects in Reversible Surface Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts","publication":"ACS Catalysis","abstract":[{"text":"Overcoming the slow kinetics of the oxygen evolution reaction at the anode is a key challenge for the production of hydrogen via electrolysis. This reaction operates at very positive potentials, where the electrocatalyst is exposed to highly oxidative conditions and prone to potential-dependent transformation of the near-surface region. While substantial evidence for such surface restructuring exists, its extent and relevance for the catalyst’s activity are unclear. We address this topic for the case of Co3O4, one of the best-known electrocatalysts exhibiting surface restructuring, by studies of epitaxial (111)-ordered electrodeposited films with combined operando X-ray surface diffraction and absorption spectroscopy, electrochemical impedance spectroscopy, and electrochemical measurements on rotating disk electrodes. Comparison of the as-prepared and annealed state of the same samples, which both are stable even under long-term oxygen evolution conditions, provides clear insight into the role of surface defects. Our results show that defect-free annealed Co3O4(111) surfaces are structurally stable over a wide potential range and hydroxylate via adsorption at surface oxygen and Co sites. Potential-induced surface restructuring of the Co3O4 lattice occurs only in the presence of surface defects, leading to the formation of the well-known nanometer-thick oxyhydroxide skin layer. The presence of this skin layer promotes oxygen evolution at low overpotentials but results in higher Tafel slopes. As a result, highly ordered Co3O4(111) surfaces are more active at high current densities than defective Co3O4 surfaces that undergo surface restructuring. These results highlight that strategies for catalyst surface defect engineering need to be application-oriented.","lang":"eng"}],"language":[{"iso":"eng"}],"keyword":["electrocatalysis","oxygen evolution reaction","cobalt spinel","operando characterization"]},{"article_type":"original","user_id":"116779","department":[{"_id":"985"}],"_id":"61982","status":"public","type":"journal_article","doi":"10.1021/acscatal.5c03900","author":[{"first_name":"L.","full_name":"Kampermann, L.","last_name":"Kampermann"},{"full_name":"Klein, J.","last_name":"Klein","first_name":"J."},{"last_name":"Wagner","full_name":"Wagner, T.","first_name":"T."},{"last_name":"Kotova","full_name":"Kotova, A.","first_name":"A."},{"last_name":"Placke-Yan","full_name":"Placke-Yan, C.","first_name":"C."},{"first_name":"A.","last_name":"Yasar","full_name":"Yasar, A."},{"first_name":"L.","full_name":"Jacobse, L.","last_name":"Jacobse"},{"first_name":"S.","last_name":"Lasagna","full_name":"Lasagna, S."},{"first_name":"Christian","last_name":"Leppin","id":"117722","full_name":"Leppin, Christian"},{"first_name":"S.","full_name":"Schulz, S.","last_name":"Schulz"},{"first_name":"Julia","last_name":"Linnemann","orcid":"0000-0001-6883-5424","id":"116779","full_name":"Linnemann, Julia"},{"full_name":"Bergmann, A.","last_name":"Bergmann","first_name":"A."},{"full_name":"Roldan Cuenya, B.","last_name":"Roldan Cuenya","first_name":"B."},{"full_name":"Bacher, G.","last_name":"Bacher","first_name":"G."}],"volume":15,"date_updated":"2025-12-07T17:15:53Z","citation":{"ama":"Kampermann L, Klein J, Wagner T, et al. Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts. ACS Catalysis. 2025;15(21):18391-18403. doi:10.1021/acscatal.5c03900","ieee":"L. Kampermann et al., “Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts,” ACS Catalysis, vol. 15, no. 21, pp. 18391–18403, 2025, doi: 10.1021/acscatal.5c03900.","chicago":"Kampermann, L., J. Klein, T. Wagner, A. Kotova, C. Placke-Yan, A. Yasar, L. Jacobse, et al. “Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts.” ACS Catalysis 15, no. 21 (2025): 18391–403. https://doi.org/10.1021/acscatal.5c03900.","short":"L. Kampermann, J. Klein, T. Wagner, A. Kotova, C. Placke-Yan, A. Yasar, L. Jacobse, S. Lasagna, C. Leppin, S. Schulz, J. Linnemann, A. Bergmann, B. Roldan Cuenya, G. Bacher, ACS Catalysis 15 (2025) 18391–18403.","mla":"Kampermann, L., et al. “Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts.” ACS Catalysis, vol. 15, no. 21, American Chemical Society (ACS), 2025, pp. 18391–403, doi:10.1021/acscatal.5c03900.","bibtex":"@article{Kampermann_Klein_Wagner_Kotova_Placke-Yan_Yasar_Jacobse_Lasagna_Leppin_Schulz_et al._2025, title={Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts}, volume={15}, DOI={10.1021/acscatal.5c03900}, number={21}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Kampermann, L. and Klein, J. and Wagner, T. and Kotova, A. and Placke-Yan, C. and Yasar, A. and Jacobse, L. and Lasagna, S. and Leppin, Christian and Schulz, S. and et al.}, year={2025}, pages={18391–18403} }","apa":"Kampermann, L., Klein, J., Wagner, T., Kotova, A., Placke-Yan, C., Yasar, A., Jacobse, L., Lasagna, S., Leppin, C., Schulz, S., Linnemann, J., Bergmann, A., Roldan Cuenya, B., & Bacher, G. (2025). Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts. ACS Catalysis, 15(21), 18391–18403. https://doi.org/10.1021/acscatal.5c03900"},"page":"18391-18403","intvolume":" 15","publication_status":"published","publication_identifier":{"issn":["2155-5435","2155-5435"]},"language":[{"iso":"eng"}],"keyword":["electrocatalysis","oxygen evolution reaction","cobalt spinel","operando characterization","spectroelectrochemistry"],"abstract":[{"text":"Doped Co3O4 nanoparticles are investigated via spectro-electrochemistry in the (pre-) oxygen evolution reaction (OER) regime by tracing the absorption signal of the Co3+ d–d transition under applied bias for getting insight into the catalysts activation and the formation of catalytically active phases. In the low potential regime up to 1.37 VRHE, a rise in the optical absorption signal of the [Co3+]oct d–d transition is observed and attributed to a structural change from [Co2+]tet to [Co3+]oct due to an electrochemically induced surface restructuring with water. For applied potentials higher than 1.37 VRHE an overall offset of the absorption spectra in the UV–vis range, equivalent to a darkening of the materials is detected. This is attributed to the formation of a CoOx(OH)y skin layer as supported by high-energy X-ray diffraction (HE-XRD) measurements. We found that the kinetics of the Co3+ states are heavily influenced by the type of dopant with V-doped Co3O4 exhibiting stable Co3+ states (>20 min) while the Mn-doped Co3O4 Co3+ states reduce within 36 s under reductive bias. We conclude that doping Co3O4 with transition metals affects the formation and potential-dependent thickness of the CoOx(OH)y skin layer as the catalytically active phase and the formation of long-time stable surface Co3+ states after activation in the first OER cycle.","lang":"eng"}],"publication":"ACS Catalysis","title":"Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4 Nanoparticle Catalysts","date_created":"2025-10-24T07:49:21Z","publisher":"American Chemical Society (ACS)","year":"2025","issue":"21","quality_controlled":"1"},{"quality_controlled":"1","issue":"7","year":"2025","publisher":"Wiley","date_created":"2025-12-18T16:57:22Z","title":"The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples","publication":"Advanced Theory and Simulations","abstract":[{"text":"AbstractThe quartz crystal microbalance with dissipation monitoring (QCM‐D) is routinely used to investigate structured samples. Here, a simulation technique is described, that predicts the shifts of frequency and half bandwidth, Δfn and ΔΓn, of a quartz resonator operating on different overtone orders, n, induced by structured samples in contact with the resonator surface in liquid. The technique, abbreviated as FreqD‐LBM, solves the Stokes equation in the frequency domain. The solution provides the complex amplitude of the area‐averaged tangential stress at the resonator surface, from which Δfn and ΔΓn are derived. Because the dynamical variables are complex amplitudes, the viscosity can be complex, as well. The technique naturally covers viscoelasticity. Limitations are linked to the grid resolution and to problems at large viscosity. Validation steps include viscoelastic films, rough surfaces, an oscillating cylinder in a viscous medium, and a free‐floating sphere above the resonator. Application examples are soft adsorbed particles, stiff adsorbed particles, and a large, immobile spherical cap above the resonator, which allows to study the high‐frequency properties of the material in the gap. FreqDLBM runs on an office PC and does not require expert knowledge of numerical techniques. It is accessible to an experimentalist.","lang":"eng"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["2513-0390","2513-0390"]},"publication_status":"published","intvolume":" 8","citation":{"chicago":"Johannsmann, Diethelm, Paul Häusner, Arne Langhoff, Christian Leppin, Ilya Reviakine, and Viktor Vanoppen. “The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples.” Advanced Theory and Simulations 8, no. 7 (2025). https://doi.org/10.1002/adts.202401373.","ieee":"D. Johannsmann, P. Häusner, A. Langhoff, C. Leppin, I. Reviakine, and V. Vanoppen, “The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples,” Advanced Theory and Simulations, vol. 8, no. 7, Art. no. 2401373, 2025, doi: 10.1002/adts.202401373.","ama":"Johannsmann D, Häusner P, Langhoff A, Leppin C, Reviakine I, Vanoppen V. The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples. Advanced Theory and Simulations. 2025;8(7). doi:10.1002/adts.202401373","short":"D. Johannsmann, P. Häusner, A. Langhoff, C. Leppin, I. Reviakine, V. Vanoppen, Advanced Theory and Simulations 8 (2025).","mla":"Johannsmann, Diethelm, et al. “The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples.” Advanced Theory and Simulations, vol. 8, no. 7, 2401373, Wiley, 2025, doi:10.1002/adts.202401373.","bibtex":"@article{Johannsmann_Häusner_Langhoff_Leppin_Reviakine_Vanoppen_2025, title={The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples}, volume={8}, DOI={10.1002/adts.202401373}, number={72401373}, journal={Advanced Theory and Simulations}, publisher={Wiley}, author={Johannsmann, Diethelm and Häusner, Paul and Langhoff, Arne and Leppin, Christian and Reviakine, Ilya and Vanoppen, Viktor}, year={2025} }","apa":"Johannsmann, D., Häusner, P., Langhoff, A., Leppin, C., Reviakine, I., & Vanoppen, V. (2025). The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples. Advanced Theory and Simulations, 8(7), Article 2401373. https://doi.org/10.1002/adts.202401373"},"date_updated":"2025-12-18T17:46:34Z","volume":8,"author":[{"last_name":"Johannsmann","full_name":"Johannsmann, Diethelm","first_name":"Diethelm"},{"first_name":"Paul","last_name":"Häusner","full_name":"Häusner, Paul"},{"last_name":"Langhoff","full_name":"Langhoff, Arne","first_name":"Arne"},{"last_name":"Leppin","id":"117722","full_name":"Leppin, Christian","first_name":"Christian"},{"first_name":"Ilya","last_name":"Reviakine","full_name":"Reviakine, Ilya"},{"last_name":"Vanoppen","full_name":"Vanoppen, Viktor","first_name":"Viktor"}],"doi":"10.1002/adts.202401373","type":"journal_article","status":"public","_id":"63223","user_id":"117722","article_type":"original","article_number":"2401373"},{"intvolume":" 11","citation":{"ieee":"M. Stich et al., “Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods,” Batteries, vol. 11, no. 7, Art. no. 273, 2025, doi: 10.3390/batteries11070273.","chicago":"Stich, Michael, Christian Leppin, Falk Thorsten Krauss, Jesus Eduardo Valdes Landa, Isabel Pantenburg, Bernhard Roling, and Andreas Bund. “Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods.” Batteries 11, no. 7 (2025). https://doi.org/10.3390/batteries11070273.","ama":"Stich M, Leppin C, Krauss FT, et al. Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods. Batteries. 2025;11(7). doi:10.3390/batteries11070273","apa":"Stich, M., Leppin, C., Krauss, F. T., Valdes Landa, J. E., Pantenburg, I., Roling, B., & Bund, A. (2025). Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods. Batteries, 11(7), Article 273. https://doi.org/10.3390/batteries11070273","bibtex":"@article{Stich_Leppin_Krauss_Valdes Landa_Pantenburg_Roling_Bund_2025, title={Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods}, volume={11}, DOI={10.3390/batteries11070273}, number={7273}, journal={Batteries}, publisher={MDPI AG}, author={Stich, Michael and Leppin, Christian and Krauss, Falk Thorsten and Valdes Landa, Jesus Eduardo and Pantenburg, Isabel and Roling, Bernhard and Bund, Andreas}, year={2025} }","short":"M. Stich, C. Leppin, F.T. Krauss, J.E. Valdes Landa, I. Pantenburg, B. Roling, A. Bund, Batteries 11 (2025).","mla":"Stich, Michael, et al. “Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods.” Batteries, vol. 11, no. 7, 273, MDPI AG, 2025, doi:10.3390/batteries11070273."},"year":"2025","issue":"7","quality_controlled":"1","publication_identifier":{"issn":["2313-0105"]},"publication_status":"published","doi":"10.3390/batteries11070273","title":"Comparing the SEI Formation on Copper and Amorphous Carbon: A Study with Combined Operando Methods","volume":11,"date_created":"2025-12-18T16:56:12Z","author":[{"last_name":"Stich","full_name":"Stich, Michael","first_name":"Michael"},{"last_name":"Leppin","id":"117722","full_name":"Leppin, Christian","first_name":"Christian"},{"first_name":"Falk Thorsten","full_name":"Krauss, Falk Thorsten","last_name":"Krauss"},{"full_name":"Valdes Landa, Jesus Eduardo","last_name":"Valdes Landa","first_name":"Jesus Eduardo"},{"full_name":"Pantenburg, Isabel","last_name":"Pantenburg","first_name":"Isabel"},{"first_name":"Bernhard","last_name":"Roling","full_name":"Roling, Bernhard"},{"first_name":"Andreas","full_name":"Bund, Andreas","last_name":"Bund"}],"publisher":"MDPI AG","date_updated":"2025-12-18T17:47:08Z","status":"public","abstract":[{"text":"The solid electrolyte interphase (SEI) on the anode of lithium-ion batteries (LIBs) has been studied thoroughly due to its crucial importance to the battery’s long-term performance. At the same time, most studies of the SEI apply ex situ characterization methods, which may introduce artifacts or misinterpretations as they do not investigate the SEI in its unaltered state immersed in liquid battery electrolyte. Thus, in this work, we focus on using the non-destructive combination of electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) and impedance spectroscopy (EIS) in the same electrochemical cell. EQCM-D can not only probe the solidified products of the SEI but also allows for the monitoring of viscoelastic layers and viscosity changes of the electrolyte at the interphase during the SEI formation. EIS complements those results by providing electrochemical properties of the formed interphase. Our results highlight substantial differences in the physical and electrochemical properties between the SEI formed on copper and on amorphous carbon and show how formation parameters and the additive vinylene carbonate (VC) influence their growth. The EQCM-D results show consistently that much thicker SEIs are formed on carbon substrates in comparison to copper substrates.","lang":"eng"}],"publication":"Batteries","type":"journal_article","language":[{"iso":"eng"}],"extern":"1","article_number":"273","article_type":"original","user_id":"117722","_id":"63222"},{"publication":"Plants","abstract":[{"text":"By monitoring the solidification of droplets of plant latices with a fast quartz crystal microbalance with dissipation monitoring (QCM-D), droplets from Campanula glomerata were found to solidify much faster than droplets from Euphorbia characias and also faster than droplets from all technical latices tested. A similar conclusion was drawn from optical videos, where the plants were injured and the milky fluid was stretched (sometimes forming fibers) after the cut. Rapid solidification cannot be explained with physical drying because physical drying is transport-limited and therefore is inherently slow. It can, however, be explained with coagulation being triggered by a sudden decrease in hydrostatic pressure. A mechanism based on a pressure drop is corroborated by optical videos of both plants being injured under water. While the liquid exuded by E. characias keeps streaming away, the liquid exuded by C. glomerata quickly forms a plug even under water. Presumably, the pressure drop causes an influx of serum into the laticifers. The serum, in turn, triggers a transition from a liquid–liquid phase separated state (an LLPS state) of a resin and hardener to a single-phase state. QCM measurements, optical videos, and cryo-SEM images suggest that LLPS plays a role in the solidification of C. glomerata.","lang":"eng"}],"language":[{"iso":"eng"}],"issue":"5","year":"2025","date_created":"2025-12-18T16:58:15Z","publisher":"MDPI AG","title":"Rapid Solidification of Plant Latices from Campanula glomerata Driven by a Sudden Decrease in Hydrostatic Pressure","type":"journal_article","status":"public","user_id":"117722","_id":"63224","extern":"1","article_type":"original","article_number":"798","publication_identifier":{"issn":["2223-7747"]},"publication_status":"published","intvolume":" 14","citation":{"apa":"Langhoff, A., Peschel, A., Leppin, C., Kruppert, S., Speck, T., & Johannsmann, D. (2025). Rapid Solidification of Plant Latices from Campanula glomerata Driven by a Sudden Decrease in Hydrostatic Pressure. Plants, 14(5), Article 798. https://doi.org/10.3390/plants14050798","short":"A. Langhoff, A. Peschel, C. Leppin, S. Kruppert, T. Speck, D. Johannsmann, Plants 14 (2025).","mla":"Langhoff, Arne, et al. “Rapid Solidification of Plant Latices from Campanula Glomerata Driven by a Sudden Decrease in Hydrostatic Pressure.” Plants, vol. 14, no. 5, 798, MDPI AG, 2025, doi:10.3390/plants14050798.","bibtex":"@article{Langhoff_Peschel_Leppin_Kruppert_Speck_Johannsmann_2025, title={Rapid Solidification of Plant Latices from Campanula glomerata Driven by a Sudden Decrease in Hydrostatic Pressure}, volume={14}, DOI={10.3390/plants14050798}, number={5798}, journal={Plants}, publisher={MDPI AG}, author={Langhoff, Arne and Peschel, Astrid and Leppin, Christian and Kruppert, Sebastian and Speck, Thomas and Johannsmann, Diethelm}, year={2025} }","chicago":"Langhoff, Arne, Astrid Peschel, Christian Leppin, Sebastian Kruppert, Thomas Speck, and Diethelm Johannsmann. “Rapid Solidification of Plant Latices from Campanula Glomerata Driven by a Sudden Decrease in Hydrostatic Pressure.” Plants 14, no. 5 (2025). https://doi.org/10.3390/plants14050798.","ieee":"A. Langhoff, A. Peschel, C. Leppin, S. Kruppert, T. Speck, and D. Johannsmann, “Rapid Solidification of Plant Latices from Campanula glomerata Driven by a Sudden Decrease in Hydrostatic Pressure,” Plants, vol. 14, no. 5, Art. no. 798, 2025, doi: 10.3390/plants14050798.","ama":"Langhoff A, Peschel A, Leppin C, Kruppert S, Speck T, Johannsmann D. Rapid Solidification of Plant Latices from Campanula glomerata Driven by a Sudden Decrease in Hydrostatic Pressure. Plants. 2025;14(5). doi:10.3390/plants14050798"},"volume":14,"author":[{"first_name":"Arne","last_name":"Langhoff","full_name":"Langhoff, Arne"},{"last_name":"Peschel","full_name":"Peschel, Astrid","first_name":"Astrid"},{"last_name":"Leppin","full_name":"Leppin, Christian","id":"117722","first_name":"Christian"},{"first_name":"Sebastian","last_name":"Kruppert","full_name":"Kruppert, Sebastian"},{"full_name":"Speck, Thomas","last_name":"Speck","first_name":"Thomas"},{"last_name":"Johannsmann","full_name":"Johannsmann, Diethelm","first_name":"Diethelm"}],"date_updated":"2025-12-18T17:41:57Z","doi":"10.3390/plants14050798"},{"publisher":"American Chemical Society (ACS)","date_created":"2025-12-18T16:59:12Z","title":"Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance","issue":"2","year":"2025","language":[{"iso":"eng"}],"publication":"Biomacromolecules","abstract":[{"text":"Various polycations and polyanions were sequentially adsorbed onto the gold electrode of a quartz crystal microbalance with dissipation monitoring. The study focused on determining the adsorption kinetics, viscoelastic properties, and electroresponsivity of polyelectrolyte layers. For the first time, it was demonstrated that the structure (compact or expanded) of the layers can be determined by electroresponsivity. Viscoelastic modeling alone did not provide a conclusive answer as to whether the layers were compact or expanded. The study was further enriched by streaming potential and contact angle measurements, where polyelectrolyte multilayers were formed on mica. It was found that successive adsorption of layers led to periodic inversion of the zeta potential. Systematic differences were observed between the different top layers, which were explained by intermixing between layers. The presence or absence of interpenetration, as determined by the measurements of streaming potential and contact angles, correlated well with electroresponsivity.","lang":"eng"}],"date_updated":"2025-12-18T17:44:44Z","volume":26,"author":[{"last_name":"Leppin","id":"117722","full_name":"Leppin, Christian","first_name":"Christian"},{"first_name":"Agata","full_name":"Pomorska, Agata","last_name":"Pomorska"},{"first_name":"Maria","full_name":"Morga, Maria","last_name":"Morga"},{"first_name":"Pawel","full_name":"Pomastowski, Pawel","last_name":"Pomastowski"},{"first_name":"Piotr","last_name":"Fijałkowski","full_name":"Fijałkowski, Piotr"},{"first_name":"Aneta","last_name":"Michna","full_name":"Michna, Aneta"},{"full_name":"Johannsmann, Diethelm","last_name":"Johannsmann","first_name":"Diethelm"}],"doi":"10.1021/acs.biomac.4c01205","publication_identifier":{"issn":["1525-7797","1526-4602"]},"publication_status":"published","intvolume":" 26","page":"914-928","citation":{"ieee":"C. Leppin et al., “Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance,” Biomacromolecules, vol. 26, no. 2, pp. 914–928, 2025, doi: 10.1021/acs.biomac.4c01205.","chicago":"Leppin, Christian, Agata Pomorska, Maria Morga, Pawel Pomastowski, Piotr Fijałkowski, Aneta Michna, and Diethelm Johannsmann. “Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance.” Biomacromolecules 26, no. 2 (2025): 914–28. https://doi.org/10.1021/acs.biomac.4c01205.","ama":"Leppin C, Pomorska A, Morga M, et al. Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance. Biomacromolecules. 2025;26(2):914-928. doi:10.1021/acs.biomac.4c01205","mla":"Leppin, Christian, et al. “Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance.” Biomacromolecules, vol. 26, no. 2, American Chemical Society (ACS), 2025, pp. 914–28, doi:10.1021/acs.biomac.4c01205.","short":"C. Leppin, A. Pomorska, M. Morga, P. Pomastowski, P. Fijałkowski, A. Michna, D. Johannsmann, Biomacromolecules 26 (2025) 914–928.","bibtex":"@article{Leppin_Pomorska_Morga_Pomastowski_Fijałkowski_Michna_Johannsmann_2025, title={Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance}, volume={26}, DOI={10.1021/acs.biomac.4c01205}, number={2}, journal={Biomacromolecules}, publisher={American Chemical Society (ACS)}, author={Leppin, Christian and Pomorska, Agata and Morga, Maria and Pomastowski, Pawel and Fijałkowski, Piotr and Michna, Aneta and Johannsmann, Diethelm}, year={2025}, pages={914–928} }","apa":"Leppin, C., Pomorska, A., Morga, M., Pomastowski, P., Fijałkowski, P., Michna, A., & Johannsmann, D. (2025). Swelling Degree of Polyelectrolyte Layers Determined by an Electrochemical Quartz Crystal Microbalance. Biomacromolecules, 26(2), 914–928. https://doi.org/10.1021/acs.biomac.4c01205"},"_id":"63225","user_id":"117722","article_type":"original","extern":"1","type":"journal_article","status":"public"},{"intvolume":" 27","page":"19733-19747","citation":{"apa":"Leppin, C., Langhoff, A., & Johannsmann, D. (2025). A fast electrochemical quartz crystal microbalance (EQCM) evidences the presence of nanobubbles in alkaline water splitting. Physical Chemistry Chemical Physics, 27(37), 19733–19747. https://doi.org/10.1039/d5cp02691a","mla":"Leppin, Christian, et al. “A Fast Electrochemical Quartz Crystal Microbalance (EQCM) Evidences the Presence of Nanobubbles in Alkaline Water Splitting.” Physical Chemistry Chemical Physics, vol. 27, no. 37, Royal Society of Chemistry (RSC), 2025, pp. 19733–47, doi:10.1039/d5cp02691a.","short":"C. Leppin, A. Langhoff, D. Johannsmann, Physical Chemistry Chemical Physics 27 (2025) 19733–19747.","bibtex":"@article{Leppin_Langhoff_Johannsmann_2025, title={A fast electrochemical quartz crystal microbalance (EQCM) evidences the presence of nanobubbles in alkaline water splitting}, volume={27}, DOI={10.1039/d5cp02691a}, number={37}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Leppin, Christian and Langhoff, Arne and Johannsmann, Diethelm}, year={2025}, pages={19733–19747} }","ama":"Leppin C, Langhoff A, Johannsmann D. A fast electrochemical quartz crystal microbalance (EQCM) evidences the presence of nanobubbles in alkaline water splitting. Physical Chemistry Chemical Physics. 2025;27(37):19733-19747. doi:10.1039/d5cp02691a","ieee":"C. Leppin, A. Langhoff, and D. Johannsmann, “A fast electrochemical quartz crystal microbalance (EQCM) evidences the presence of nanobubbles in alkaline water splitting,” Physical Chemistry Chemical Physics, vol. 27, no. 37, pp. 19733–19747, 2025, doi: 10.1039/d5cp02691a.","chicago":"Leppin, Christian, Arne Langhoff, and Diethelm Johannsmann. “A Fast Electrochemical Quartz Crystal Microbalance (EQCM) Evidences the Presence of Nanobubbles in Alkaline Water Splitting.” Physical Chemistry Chemical Physics 27, no. 37 (2025): 19733–47. https://doi.org/10.1039/d5cp02691a."},"year":"2025","issue":"37","publication_identifier":{"issn":["1463-9076","1463-9084"]},"publication_status":"published","doi":"10.1039/d5cp02691a","title":"A fast electrochemical quartz crystal microbalance (EQCM) evidences the presence of nanobubbles in alkaline water splitting","volume":27,"date_created":"2025-12-18T17:00:11Z","author":[{"first_name":"Christian","last_name":"Leppin","id":"117722","full_name":"Leppin, Christian"},{"full_name":"Langhoff, Arne","last_name":"Langhoff","first_name":"Arne"},{"full_name":"Johannsmann, Diethelm","last_name":"Johannsmann","first_name":"Diethelm"}],"publisher":"Royal Society of Chemistry (RSC)","date_updated":"2025-12-18T17:43:25Z","status":"public","abstract":[{"lang":"eng","text":"Nanobubbles in water splitting are recognized by the EQCM-D. They are ubiquitous. Lifetimes are in the range of seconds."}],"publication":"Physical Chemistry Chemical Physics","type":"journal_article","extern":"1","language":[{"iso":"eng"}],"article_type":"original","user_id":"117722","_id":"63226"},{"date_created":"2025-12-18T17:01:44Z","publisher":"Royal Society of Chemistry (RSC)","title":"An electrochemical quartz crystal microbalance (EQCM) based on microelectrode arrays allows to distinguish between adsorption and electrodeposition","issue":"7","quality_controlled":"1","year":"2024","language":[{"iso":"eng"}],"publication":"The Analyst","abstract":[{"text":"Using a precise electrochemical quartz crystal microbalance (EQCM), it was shown that electrogravimetry can be carried out with microelectrode arrays (MEAs). Significant differences between the potential dependent adsorption of a redox-active molecule and electroplating were presented.","lang":"eng"}],"volume":149,"author":[{"first_name":"Michael","last_name":"Biermann","full_name":"Biermann, Michael"},{"first_name":"Christian","full_name":"Leppin, Christian","id":"117722","last_name":"Leppin"},{"first_name":"Arne","full_name":"Langhoff, Arne","last_name":"Langhoff"},{"first_name":"Thorben","full_name":"Ziemer, Thorben","last_name":"Ziemer"},{"full_name":"Rembe, Christian","last_name":"Rembe","first_name":"Christian"},{"last_name":"Johannsmann","full_name":"Johannsmann, Diethelm","first_name":"Diethelm"}],"date_updated":"2025-12-18T17:42:48Z","doi":"10.1039/d3an02210b","publication_identifier":{"issn":["0003-2654","1364-5528"]},"publication_status":"published","intvolume":" 149","page":"2138-2146","citation":{"ama":"Biermann M, Leppin C, Langhoff A, Ziemer T, Rembe C, Johannsmann D. An electrochemical quartz crystal microbalance (EQCM) based on microelectrode arrays allows to distinguish between adsorption and electrodeposition. The Analyst. 2024;149(7):2138-2146. doi:10.1039/d3an02210b","chicago":"Biermann, Michael, Christian Leppin, Arne Langhoff, Thorben Ziemer, Christian Rembe, and Diethelm Johannsmann. “An Electrochemical Quartz Crystal Microbalance (EQCM) Based on Microelectrode Arrays Allows to Distinguish between Adsorption and Electrodeposition.” The Analyst 149, no. 7 (2024): 2138–46. https://doi.org/10.1039/d3an02210b.","ieee":"M. Biermann, C. Leppin, A. Langhoff, T. Ziemer, C. Rembe, and D. Johannsmann, “An electrochemical quartz crystal microbalance (EQCM) based on microelectrode arrays allows to distinguish between adsorption and electrodeposition,” The Analyst, vol. 149, no. 7, pp. 2138–2146, 2024, doi: 10.1039/d3an02210b.","bibtex":"@article{Biermann_Leppin_Langhoff_Ziemer_Rembe_Johannsmann_2024, title={An electrochemical quartz crystal microbalance (EQCM) based on microelectrode arrays allows to distinguish between adsorption and electrodeposition}, volume={149}, DOI={10.1039/d3an02210b}, number={7}, journal={The Analyst}, publisher={Royal Society of Chemistry (RSC)}, author={Biermann, Michael and Leppin, Christian and Langhoff, Arne and Ziemer, Thorben and Rembe, Christian and Johannsmann, Diethelm}, year={2024}, pages={2138–2146} }","short":"M. Biermann, C. Leppin, A. Langhoff, T. Ziemer, C. Rembe, D. Johannsmann, The Analyst 149 (2024) 2138–2146.","mla":"Biermann, Michael, et al. “An Electrochemical Quartz Crystal Microbalance (EQCM) Based on Microelectrode Arrays Allows to Distinguish between Adsorption and Electrodeposition.” The Analyst, vol. 149, no. 7, Royal Society of Chemistry (RSC), 2024, pp. 2138–46, doi:10.1039/d3an02210b.","apa":"Biermann, M., Leppin, C., Langhoff, A., Ziemer, T., Rembe, C., & Johannsmann, D. (2024). An electrochemical quartz crystal microbalance (EQCM) based on microelectrode arrays allows to distinguish between adsorption and electrodeposition. The Analyst, 149(7), 2138–2146. https://doi.org/10.1039/d3an02210b"},"user_id":"117722","_id":"63227","extern":"1","article_type":"original","type":"journal_article","status":"public"},{"publication_status":"published","publication_identifier":{"issn":["0003-2654","1364-5528"]},"citation":{"ieee":"E. Rott, C. Leppin, T. Diederichs, P. Garidel, and D. Johannsmann, “Protein–protein interactions in solutions of monoclonal antibodies probed by the dependence of the high-frequency viscosity on temperature and concentration,” The Analyst, vol. 148, no. 8, pp. 1887–1897, 2023, doi: 10.1039/d3an00076a.","chicago":"Rott, Emily, Christian Leppin, Tim Diederichs, Patrick Garidel, and Diethelm Johannsmann. “Protein–Protein Interactions in Solutions of Monoclonal Antibodies Probed by the Dependence of the High-Frequency Viscosity on Temperature and Concentration.” The Analyst 148, no. 8 (2023): 1887–97. https://doi.org/10.1039/d3an00076a.","ama":"Rott E, Leppin C, Diederichs T, Garidel P, Johannsmann D. Protein–protein interactions in solutions of monoclonal antibodies probed by the dependence of the high-frequency viscosity on temperature and concentration. The Analyst. 2023;148(8):1887-1897. doi:10.1039/d3an00076a","apa":"Rott, E., Leppin, C., Diederichs, T., Garidel, P., & Johannsmann, D. (2023). Protein–protein interactions in solutions of monoclonal antibodies probed by the dependence of the high-frequency viscosity on temperature and concentration. The Analyst, 148(8), 1887–1897. https://doi.org/10.1039/d3an00076a","bibtex":"@article{Rott_Leppin_Diederichs_Garidel_Johannsmann_2023, title={Protein–protein interactions in solutions of monoclonal antibodies probed by the dependence of the high-frequency viscosity on temperature and concentration}, volume={148}, DOI={10.1039/d3an00076a}, number={8}, journal={The Analyst}, publisher={Royal Society of Chemistry (RSC)}, author={Rott, Emily and Leppin, Christian and Diederichs, Tim and Garidel, Patrick and Johannsmann, Diethelm}, year={2023}, pages={1887–1897} }","mla":"Rott, Emily, et al. “Protein–Protein Interactions in Solutions of Monoclonal Antibodies Probed by the Dependence of the High-Frequency Viscosity on Temperature and Concentration.” The Analyst, vol. 148, no. 8, Royal Society of Chemistry (RSC), 2023, pp. 1887–97, doi:10.1039/d3an00076a.","short":"E. Rott, C. Leppin, T. Diederichs, P. Garidel, D. Johannsmann, The Analyst 148 (2023) 1887–1897."},"page":"1887-1897","intvolume":" 148","author":[{"last_name":"Rott","full_name":"Rott, Emily","first_name":"Emily"},{"first_name":"Christian","id":"117722","full_name":"Leppin, Christian","last_name":"Leppin"},{"full_name":"Diederichs, Tim","last_name":"Diederichs","first_name":"Tim"},{"full_name":"Garidel, Patrick","last_name":"Garidel","first_name":"Patrick"},{"full_name":"Johannsmann, Diethelm","last_name":"Johannsmann","first_name":"Diethelm"}],"volume":148,"date_updated":"2025-12-18T17:38:31Z","doi":"10.1039/d3an00076a","type":"journal_article","status":"public","user_id":"117722","_id":"63231","issue":"8","quality_controlled":"1","year":"2023","date_created":"2025-12-18T17:06:08Z","publisher":"Royal Society of Chemistry (RSC)","title":"Protein–protein interactions in solutions of monoclonal antibodies probed by the dependence of the high-frequency viscosity on temperature and concentration","publication":"The Analyst","abstract":[{"text":"\r\n A QCM-D probes the temperature- and concentration-dependent complex high-frequency viscosity and provides information on protein-protein interactions in solutions of monoclonal antibodies.","lang":"eng"}],"language":[{"iso":"eng"}]},{"article_type":"original","article_number":"2300190","extern":"1","_id":"63228","user_id":"117722","status":"public","type":"journal_article","doi":"10.1002/adts.202300190","date_updated":"2025-12-18T17:41:08Z","volume":6,"author":[{"last_name":"Johannsmann","full_name":"Johannsmann, Diethelm","first_name":"Diethelm"},{"full_name":"Leppin, Christian","id":"117722","last_name":"Leppin","first_name":"Christian"},{"last_name":"Langhoff","full_name":"Langhoff, Arne","first_name":"Arne"}],"intvolume":" 6","citation":{"ieee":"D. Johannsmann, C. Leppin, and A. Langhoff, “Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation,” Advanced Theory and Simulations, vol. 6, no. 11, Art. no. 2300190, 2023, doi: 10.1002/adts.202300190.","chicago":"Johannsmann, Diethelm, Christian Leppin, and Arne Langhoff. “Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation.” Advanced Theory and Simulations 6, no. 11 (2023). https://doi.org/10.1002/adts.202300190.","ama":"Johannsmann D, Leppin C, Langhoff A. Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation. Advanced Theory and Simulations. 2023;6(11). doi:10.1002/adts.202300190","apa":"Johannsmann, D., Leppin, C., & Langhoff, A. (2023). Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation. Advanced Theory and Simulations, 6(11), Article 2300190. https://doi.org/10.1002/adts.202300190","short":"D. Johannsmann, C. Leppin, A. Langhoff, Advanced Theory and Simulations 6 (2023).","mla":"Johannsmann, Diethelm, et al. “Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation.” Advanced Theory and Simulations, vol. 6, no. 11, 2300190, Wiley, 2023, doi:10.1002/adts.202300190.","bibtex":"@article{Johannsmann_Leppin_Langhoff_2023, title={Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation}, volume={6}, DOI={10.1002/adts.202300190}, number={112300190}, journal={Advanced Theory and Simulations}, publisher={Wiley}, author={Johannsmann, Diethelm and Leppin, Christian and Langhoff, Arne}, year={2023} }"},"publication_identifier":{"issn":["2513-0390","2513-0390"]},"publication_status":"published","language":[{"iso":"eng"}],"abstract":[{"lang":"eng","text":"AbstractA simulation based on the frequency‐domain lattice Boltzmann method (FreqD‐LBM) is employed to predict the shifts of resonance frequency, Δf, and half bandwidth, ΔΓ, of a quartz crystal microbalance with dissipation monitoring (QCM‐D) induced by the adsorption of rigid spheres to the resonator surface. The comparison with the experimental values of Δf and ΔΓ allows to estimate the stiffness of the contacts between the spheres and the resonator surface. The contact stiffness is of interest in contact mechanics, but also in sensing because it depends on the properties of thin films situated between the resonator surface and the sphere. The simulation differs from previous implementations of FreqD‐LBM insofar, as the material inside the particles is not included in the FreqD‐LBM algorithm. Rather, the particle surface is configured to be an oscillating boundary. The amplitude of the particles' motions (displacement and rotation) is governed by the force balance at the surface of the particle. Because the contact stiffness enters this balance, it can be derived from experimental values of Δf and ΔΓ. The simulation reproduces experiments by the Krakow group. For sufficiently small spheres, a contact stiffness can be derived from the comparison of the simulation with the experiment."}],"publication":"Advanced Theory and Simulations","title":"Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation","publisher":"Wiley","date_created":"2025-12-18T17:03:12Z","year":"2023","quality_controlled":"1","issue":"11"},{"doi":"10.3390/s23031348","title":"Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model","volume":23,"author":[{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"},{"full_name":"Langhoff, Arne","last_name":"Langhoff","first_name":"Arne"},{"last_name":"Leppin","full_name":"Leppin, Christian","id":"117722","first_name":"Christian"},{"first_name":"Ilya","last_name":"Reviakine","full_name":"Reviakine, Ilya"},{"full_name":"Maan, Anna M. C.","last_name":"Maan","first_name":"Anna M. C."}],"date_created":"2025-12-18T17:05:00Z","date_updated":"2025-12-18T17:39:52Z","publisher":"MDPI AG","intvolume":" 23","citation":{"mla":"Johannsmann, Diethelm, et al. “Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model.” Sensors, vol. 23, no. 3, 1348, MDPI AG, 2023, doi:10.3390/s23031348.","short":"D. Johannsmann, A. Langhoff, C. Leppin, I. Reviakine, A.M.C. Maan, Sensors 23 (2023).","bibtex":"@article{Johannsmann_Langhoff_Leppin_Reviakine_Maan_2023, title={Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model}, volume={23}, DOI={10.3390/s23031348}, number={31348}, journal={Sensors}, publisher={MDPI AG}, author={Johannsmann, Diethelm and Langhoff, Arne and Leppin, Christian and Reviakine, Ilya and Maan, Anna M. C.}, year={2023} }","apa":"Johannsmann, D., Langhoff, A., Leppin, C., Reviakine, I., & Maan, A. M. C. (2023). Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model. Sensors, 23(3), Article 1348. https://doi.org/10.3390/s23031348","ama":"Johannsmann D, Langhoff A, Leppin C, Reviakine I, Maan AMC. Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model. Sensors. 2023;23(3). doi:10.3390/s23031348","chicago":"Johannsmann, Diethelm, Arne Langhoff, Christian Leppin, Ilya Reviakine, and Anna M. C. Maan. “Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model.” Sensors 23, no. 3 (2023). https://doi.org/10.3390/s23031348.","ieee":"D. Johannsmann, A. Langhoff, C. Leppin, I. Reviakine, and A. M. C. Maan, “Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model,” Sensors, vol. 23, no. 3, Art. no. 1348, 2023, doi: 10.3390/s23031348."},"year":"2023","issue":"3","quality_controlled":"1","publication_identifier":{"issn":["1424-8220"]},"publication_status":"published","extern":"1","language":[{"iso":"eng"}],"article_number":"1348","user_id":"117722","_id":"63230","status":"public","abstract":[{"lang":"eng","text":"Quartz crystal microbalance with dissipation monitoring (QCM-D) is a well-established technique for studying soft films. It can provide gravimetric as well as nongravimetric information about a film, such as its thickness and mechanical properties. The interpretation of sets of overtone-normalized frequency shifts, ∆f/n, and overtone-normalized shifts in half-bandwidth, ΔΓ/n, provided by QCM-D relies on a model that, in general, contains five independent parameters that are needed to describe film thickness and frequency-dependent viscoelastic properties. Here, we examine how noise inherent in experimental data affects the determination of these parameters. There are certain conditions where noise prevents the reliable determination of film thickness and the loss tangent. On the other hand, we show that there are conditions where it is possible to determine all five parameters. We relate these conditions to the mathematical properties of the model in terms of simple conceptual diagrams that can help users understand the model’s behavior. Finally, we present new open source software for QCM-D data analysis written in Python, PyQTM."}],"publication":"Sensors","type":"journal_article"},{"user_id":"117722","_id":"63229","extern":"1","language":[{"iso":"eng"}],"article_number":"106219","publication":"Results in Physics","type":"journal_article","status":"public","volume":45,"date_created":"2025-12-18T17:04:13Z","author":[{"first_name":"Diethelm","full_name":"Johannsmann, Diethelm","last_name":"Johannsmann"},{"first_name":"Judith","last_name":"Petri","full_name":"Petri, Judith"},{"last_name":"Leppin","full_name":"Leppin, Christian","id":"117722","first_name":"Christian"},{"first_name":"Arne","last_name":"Langhoff","full_name":"Langhoff, Arne"},{"first_name":"Hozan","last_name":"Ibrahim","full_name":"Ibrahim, Hozan"}],"date_updated":"2025-12-18T17:40:25Z","publisher":"Elsevier BV","doi":"10.1016/j.rinp.2023.106219","title":"Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method","publication_identifier":{"issn":["2211-3797"]},"publication_status":"published","intvolume":" 45","citation":{"ama":"Johannsmann D, Petri J, Leppin C, Langhoff A, Ibrahim H. Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method. Results in Physics. 2023;45. doi:10.1016/j.rinp.2023.106219","chicago":"Johannsmann, Diethelm, Judith Petri, Christian Leppin, Arne Langhoff, and Hozan Ibrahim. “Particle Fouling at Hot Reactor Walls Monitored In Situ with a QCM-D and Modeled with the Frequency-Domain Lattice Boltzmann Method.” Results in Physics 45 (2023). https://doi.org/10.1016/j.rinp.2023.106219.","ieee":"D. Johannsmann, J. Petri, C. Leppin, A. Langhoff, and H. Ibrahim, “Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method,” Results in Physics, vol. 45, Art. no. 106219, 2023, doi: 10.1016/j.rinp.2023.106219.","apa":"Johannsmann, D., Petri, J., Leppin, C., Langhoff, A., & Ibrahim, H. (2023). Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method. Results in Physics, 45, Article 106219. https://doi.org/10.1016/j.rinp.2023.106219","short":"D. Johannsmann, J. Petri, C. Leppin, A. Langhoff, H. Ibrahim, Results in Physics 45 (2023).","mla":"Johannsmann, Diethelm, et al. “Particle Fouling at Hot Reactor Walls Monitored In Situ with a QCM-D and Modeled with the Frequency-Domain Lattice Boltzmann Method.” Results in Physics, vol. 45, 106219, Elsevier BV, 2023, doi:10.1016/j.rinp.2023.106219.","bibtex":"@article{Johannsmann_Petri_Leppin_Langhoff_Ibrahim_2023, title={Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method}, volume={45}, DOI={10.1016/j.rinp.2023.106219}, number={106219}, journal={Results in Physics}, publisher={Elsevier BV}, author={Johannsmann, Diethelm and Petri, Judith and Leppin, Christian and Langhoff, Arne and Ibrahim, Hozan}, year={2023} }"},"year":"2023"},{"author":[{"last_name":"Wiegmann","full_name":"Wiegmann, Jens","first_name":"Jens"},{"first_name":"Christian","id":"117722","full_name":"Leppin, Christian","last_name":"Leppin"},{"first_name":"Arne","full_name":"Langhoff, Arne","last_name":"Langhoff"},{"first_name":"Jan","last_name":"Schwaderer","full_name":"Schwaderer, Jan"},{"last_name":"Beuermann","full_name":"Beuermann, Sabine","first_name":"Sabine"},{"full_name":"Johannsmann, Diethelm","last_name":"Johannsmann","first_name":"Diethelm"},{"full_name":"Weber, Alfred P.","last_name":"Weber","first_name":"Alfred P."}],"date_created":"2025-12-18T17:22:31Z","volume":33,"date_updated":"2025-12-18T17:37:31Z","publisher":"Elsevier BV","doi":"10.1016/j.apt.2022.103452","title":"Influence of the solvent evaporation rate on the β-Phase content of electrosprayed PVDF particles and films studied by a fast Multi-Overtone QCM","issue":"3","publication_status":"published","publication_identifier":{"issn":["0921-8831"]},"quality_controlled":"1","citation":{"short":"J. Wiegmann, C. Leppin, A. Langhoff, J. Schwaderer, S. Beuermann, D. Johannsmann, A.P. Weber, Advanced Powder Technology 33 (2022).","bibtex":"@article{Wiegmann_Leppin_Langhoff_Schwaderer_Beuermann_Johannsmann_Weber_2022, title={Influence of the solvent evaporation rate on the β-Phase content of electrosprayed PVDF particles and films studied by a fast Multi-Overtone QCM}, volume={33}, DOI={10.1016/j.apt.2022.103452}, number={3103452}, journal={Advanced Powder Technology}, publisher={Elsevier BV}, author={Wiegmann, Jens and Leppin, Christian and Langhoff, Arne and Schwaderer, Jan and Beuermann, Sabine and Johannsmann, Diethelm and Weber, Alfred P.}, year={2022} }","mla":"Wiegmann, Jens, et al. “Influence of the Solvent Evaporation Rate on the β-Phase Content of Electrosprayed PVDF Particles and Films Studied by a Fast Multi-Overtone QCM.” Advanced Powder Technology, vol. 33, no. 3, 103452, Elsevier BV, 2022, doi:10.1016/j.apt.2022.103452.","apa":"Wiegmann, J., Leppin, C., Langhoff, A., Schwaderer, J., Beuermann, S., Johannsmann, D., & Weber, A. P. (2022). Influence of the solvent evaporation rate on the β-Phase content of electrosprayed PVDF particles and films studied by a fast Multi-Overtone QCM. Advanced Powder Technology, 33(3), Article 103452. https://doi.org/10.1016/j.apt.2022.103452","ama":"Wiegmann J, Leppin C, Langhoff A, et al. Influence of the solvent evaporation rate on the β-Phase content of electrosprayed PVDF particles and films studied by a fast Multi-Overtone QCM. Advanced Powder Technology. 2022;33(3). doi:10.1016/j.apt.2022.103452","chicago":"Wiegmann, Jens, Christian Leppin, Arne Langhoff, Jan Schwaderer, Sabine Beuermann, Diethelm Johannsmann, and Alfred P. Weber. “Influence of the Solvent Evaporation Rate on the β-Phase Content of Electrosprayed PVDF Particles and Films Studied by a Fast Multi-Overtone QCM.” Advanced Powder Technology 33, no. 3 (2022). https://doi.org/10.1016/j.apt.2022.103452.","ieee":"J. Wiegmann et al., “Influence of the solvent evaporation rate on the β-Phase content of electrosprayed PVDF particles and films studied by a fast Multi-Overtone QCM,” Advanced Powder Technology, vol. 33, no. 3, Art. no. 103452, 2022, doi: 10.1016/j.apt.2022.103452."},"intvolume":" 33","year":"2022","user_id":"117722","_id":"63234","language":[{"iso":"eng"}],"extern":"1","article_number":"103452","type":"journal_article","publication":"Advanced Powder Technology","status":"public"},{"volume":94,"author":[{"first_name":"Christian","full_name":"Leppin, Christian","id":"117722","last_name":"Leppin"},{"first_name":"Arne","full_name":"Langhoff, Arne","last_name":"Langhoff"},{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"}],"date_updated":"2025-12-18T17:38:07Z","doi":"10.1021/acs.analchem.2c01763","publication_identifier":{"issn":["0003-2700","1520-6882"]},"publication_status":"published","page":"10227-10233","intvolume":" 94","citation":{"ama":"Leppin C, Langhoff A, Johannsmann D. Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions. Analytical Chemistry. 2022;94(28):10227-10233. doi:10.1021/acs.analchem.2c01763","ieee":"C. Leppin, A. Langhoff, and D. Johannsmann, “Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions,” Analytical Chemistry, vol. 94, no. 28, pp. 10227–10233, 2022, doi: 10.1021/acs.analchem.2c01763.","chicago":"Leppin, Christian, Arne Langhoff, and Diethelm Johannsmann. “Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions.” Analytical Chemistry 94, no. 28 (2022): 10227–33. https://doi.org/10.1021/acs.analchem.2c01763.","apa":"Leppin, C., Langhoff, A., & Johannsmann, D. (2022). Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions. Analytical Chemistry, 94(28), 10227–10233. https://doi.org/10.1021/acs.analchem.2c01763","mla":"Leppin, Christian, et al. “Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions.” Analytical Chemistry, vol. 94, no. 28, American Chemical Society (ACS), 2022, pp. 10227–33, doi:10.1021/acs.analchem.2c01763.","short":"C. Leppin, A. Langhoff, D. Johannsmann, Analytical Chemistry 94 (2022) 10227–10233.","bibtex":"@article{Leppin_Langhoff_Johannsmann_2022, title={Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions}, volume={94}, DOI={10.1021/acs.analchem.2c01763}, number={28}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Leppin, Christian and Langhoff, Arne and Johannsmann, Diethelm}, year={2022}, pages={10227–10233} }"},"user_id":"117722","_id":"63233","extern":"1","type":"journal_article","status":"public","date_created":"2025-12-18T17:21:21Z","publisher":"American Chemical Society (ACS)","title":"Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions","issue":"28","quality_controlled":"1","year":"2022","language":[{"iso":"eng"}],"publication":"Analytical Chemistry"},{"publisher":"MDPI AG","date_updated":"2025-12-18T17:36:06Z","date_created":"2025-12-18T17:25:13Z","author":[{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"},{"first_name":"Arne","last_name":"Langhoff","full_name":"Langhoff, Arne"},{"first_name":"Christian","full_name":"Leppin, Christian","id":"117722","last_name":"Leppin"}],"volume":21,"title":"Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM)","doi":"10.3390/s21103490","publication_status":"published","publication_identifier":{"issn":["1424-8220"]},"quality_controlled":"1","issue":"10","year":"2021","citation":{"ama":"Johannsmann D, Langhoff A, Leppin C. Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM). Sensors. 2021;21(10). doi:10.3390/s21103490","chicago":"Johannsmann, Diethelm, Arne Langhoff, and Christian Leppin. “Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM).” Sensors 21, no. 10 (2021). https://doi.org/10.3390/s21103490.","ieee":"D. Johannsmann, A. Langhoff, and C. Leppin, “Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM),” Sensors, vol. 21, no. 10, Art. no. 3490, 2021, doi: 10.3390/s21103490.","apa":"Johannsmann, D., Langhoff, A., & Leppin, C. (2021). Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM). Sensors, 21(10), Article 3490. https://doi.org/10.3390/s21103490","bibtex":"@article{Johannsmann_Langhoff_Leppin_2021, title={Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM)}, volume={21}, DOI={10.3390/s21103490}, number={103490}, journal={Sensors}, publisher={MDPI AG}, author={Johannsmann, Diethelm and Langhoff, Arne and Leppin, Christian}, year={2021} }","short":"D. Johannsmann, A. Langhoff, C. Leppin, Sensors 21 (2021).","mla":"Johannsmann, Diethelm, et al. “Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM).” Sensors, vol. 21, no. 10, 3490, MDPI AG, 2021, doi:10.3390/s21103490."},"intvolume":" 21","_id":"63236","user_id":"117722","article_number":"3490","extern":"1","language":[{"iso":"eng"}],"type":"journal_article","publication":"Sensors","abstract":[{"text":"The response of the quartz crystal microbalance (QCM, also: QCM-D for “QCM with Dissipation monitoring”) to loading with a diverse set of samples is reviewed in a consistent frame. After a brief introduction to the advanced QCMs, the governing equation (the small-load approximation) is derived. Planar films and adsorbates are modeled based on the acoustic multilayer formalism. In liquid environments, viscoelastic spectroscopy and high-frequency rheology are possible, even on layers with a thickness in the monolayer range. For particulate samples, the contact stiffness can be derived. Because the stress at the contact is large, the force is not always proportional to the displacement. Nonlinear effects are observed, leading to a dependence of the resonance frequency and the resonance bandwidth on the amplitude of oscillation. Partial slip, in particular, can be studied in detail. Advanced topics include structured samples and the extension of the small-load approximation to its tensorial version.","lang":"eng"}],"status":"public"},{"status":"public","type":"journal_article","extern":"1","user_id":"117722","_id":"63235","intvolume":" 33","page":"2529-2538","citation":{"ama":"Leppin C, Langhoff A, Höfft O, Johannsmann D. A Modulation QCM Applied to Copper Electrodeposition and Stripping. Electroanalysis. 2021;33(12):2529-2538. doi:10.1002/elan.202100471","chicago":"Leppin, Christian, Arne Langhoff, Oliver Höfft, and Diethelm Johannsmann. “A Modulation QCM Applied to Copper Electrodeposition and Stripping.” Electroanalysis 33, no. 12 (2021): 2529–38. https://doi.org/10.1002/elan.202100471.","ieee":"C. Leppin, A. Langhoff, O. Höfft, and D. Johannsmann, “A Modulation QCM Applied to Copper Electrodeposition and Stripping,” Electroanalysis, vol. 33, no. 12, pp. 2529–2538, 2021, doi: 10.1002/elan.202100471.","bibtex":"@article{Leppin_Langhoff_Höfft_Johannsmann_2021, title={A Modulation QCM Applied to Copper Electrodeposition and Stripping}, volume={33}, DOI={10.1002/elan.202100471}, number={12}, journal={Electroanalysis}, publisher={Wiley}, author={Leppin, Christian and Langhoff, Arne and Höfft, Oliver and Johannsmann, Diethelm}, year={2021}, pages={2529–2538} }","short":"C. Leppin, A. Langhoff, O. Höfft, D. Johannsmann, Electroanalysis 33 (2021) 2529–2538.","mla":"Leppin, Christian, et al. “A Modulation QCM Applied to Copper Electrodeposition and Stripping.” Electroanalysis, vol. 33, no. 12, Wiley, 2021, pp. 2529–38, doi:10.1002/elan.202100471.","apa":"Leppin, C., Langhoff, A., Höfft, O., & Johannsmann, D. (2021). A Modulation QCM Applied to Copper Electrodeposition and Stripping. Electroanalysis, 33(12), 2529–2538. https://doi.org/10.1002/elan.202100471"},"publication_identifier":{"issn":["1040-0397","1521-4109"]},"publication_status":"published","doi":"10.1002/elan.202100471","volume":33,"author":[{"last_name":"Leppin","id":"117722","full_name":"Leppin, Christian","first_name":"Christian"},{"last_name":"Langhoff","full_name":"Langhoff, Arne","first_name":"Arne"},{"first_name":"Oliver","last_name":"Höfft","full_name":"Höfft, Oliver"},{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"}],"date_updated":"2025-12-18T17:36:54Z","abstract":[{"text":"AbstractA fast electrochemical quartz crystal microbalance with dissipation monitoring (EQCM−D) was applied to copper electrodeposition and subsequent stripping. Accumulation brings the frequency noise down to the mHz range, corresponding to 0.1 % of a monolayer. With this precision, the apparent mass transfer rate as determined from the time‐derivative of the frequency shift can be directly compared to the current. Small but systematic deviations between the two can be attributed to nanoscale roughness. In the voltage range of underpotential deposition (UPD), the apparent mass transfer rate shows peaks and shoulders. The plating additive benzotriazole (BTA) leaves the magnitude of electrogravimetric signals unchanged, but shifts the UPD onset potential. The additive thiourea (TU) promotes UPD and strongly increases the bandwidth.","lang":"eng"}],"publication":"Electroanalysis","language":[{"iso":"eng"}],"year":"2021","issue":"12","quality_controlled":"1","title":"A Modulation QCM Applied to Copper Electrodeposition and Stripping","date_created":"2025-12-18T17:23:58Z","publisher":"Wiley"},{"year":"2021","issue":"19","quality_controlled":"1","title":"Fast and slow EQCM response of zwitterionic weak electrolytes to changes in the electrode potential: a pH-mediated mechanism","date_created":"2025-12-18T17:26:31Z","publisher":"Royal Society of Chemistry (RSC)","abstract":[{"lang":"eng","text":"Using a fast electrochemical quartz crystal microbalance (EQCM), zwitterionic electrolytes were studied with regard to changes of resonance frequency and resonance bandwidth after the electrode potential was switched."}],"publication":"The Analyst","language":[{"iso":"eng"}],"intvolume":" 146","page":"6005-6013","citation":{"ieee":"C. Leppin, A. Langhoff, H.-F. Poggemann, A. S. Gödde, and D. Johannsmann, “Fast and slow EQCM response of zwitterionic weak electrolytes to changes in the electrode potential: a pH-mediated mechanism,” The Analyst, vol. 146, no. 19, pp. 6005–6013, 2021, doi: 10.1039/d1an01306h.","chicago":"Leppin, Christian, Arne Langhoff, Hanna-Friederike Poggemann, Alexander Simon Gödde, and Diethelm Johannsmann. “Fast and Slow EQCM Response of Zwitterionic Weak Electrolytes to Changes in the Electrode Potential: A PH-Mediated Mechanism.” The Analyst 146, no. 19 (2021): 6005–13. https://doi.org/10.1039/d1an01306h.","ama":"Leppin C, Langhoff A, Poggemann H-F, Gödde AS, Johannsmann D. Fast and slow EQCM response of zwitterionic weak electrolytes to changes in the electrode potential: a pH-mediated mechanism. The Analyst. 2021;146(19):6005-6013. doi:10.1039/d1an01306h","apa":"Leppin, C., Langhoff, A., Poggemann, H.-F., Gödde, A. S., & Johannsmann, D. (2021). Fast and slow EQCM response of zwitterionic weak electrolytes to changes in the electrode potential: a pH-mediated mechanism. The Analyst, 146(19), 6005–6013. https://doi.org/10.1039/d1an01306h","mla":"Leppin, Christian, et al. “Fast and Slow EQCM Response of Zwitterionic Weak Electrolytes to Changes in the Electrode Potential: A PH-Mediated Mechanism.” The Analyst, vol. 146, no. 19, Royal Society of Chemistry (RSC), 2021, pp. 6005–13, doi:10.1039/d1an01306h.","bibtex":"@article{Leppin_Langhoff_Poggemann_Gödde_Johannsmann_2021, title={Fast and slow EQCM response of zwitterionic weak electrolytes to changes in the electrode potential: a pH-mediated mechanism}, volume={146}, DOI={10.1039/d1an01306h}, number={19}, journal={The Analyst}, publisher={Royal Society of Chemistry (RSC)}, author={Leppin, Christian and Langhoff, Arne and Poggemann, Hanna-Friederike and Gödde, Alexander Simon and Johannsmann, Diethelm}, year={2021}, pages={6005–6013} }","short":"C. Leppin, A. Langhoff, H.-F. Poggemann, A.S. Gödde, D. Johannsmann, The Analyst 146 (2021) 6005–6013."},"publication_identifier":{"issn":["0003-2654","1364-5528"]},"publication_status":"published","doi":"10.1039/d1an01306h","volume":146,"author":[{"id":"117722","full_name":"Leppin, Christian","last_name":"Leppin","first_name":"Christian"},{"full_name":"Langhoff, Arne","last_name":"Langhoff","first_name":"Arne"},{"first_name":"Hanna-Friederike","full_name":"Poggemann, Hanna-Friederike","last_name":"Poggemann"},{"first_name":"Alexander Simon","full_name":"Gödde, Alexander Simon","last_name":"Gödde"},{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"}],"date_updated":"2025-12-18T17:35:11Z","status":"public","type":"journal_article","extern":"1","user_id":"117722","_id":"63237"},{"type":"journal_article","publication":"The Analyst","status":"public","abstract":[{"lang":"eng","text":"

A fast EQCM measures the kinetics of the viscosity changes inside the double layer following voltage jumps.

"}],"user_id":"117722","_id":"63238","extern":"1","language":[{"iso":"eng"}],"issue":"7","publication_status":"published","quality_controlled":"1","publication_identifier":{"issn":["0003-2654","1364-5528"]},"citation":{"ama":"Leppin C, Peschel A, Meyer FS, Langhoff A, Johannsmann D. Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM). The Analyst. 2021;146(7):2160-2171. doi:10.1039/d0an01965h","ieee":"C. Leppin, A. Peschel, F. S. Meyer, A. Langhoff, and D. Johannsmann, “Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM),” The Analyst, vol. 146, no. 7, pp. 2160–2171, 2021, doi: 10.1039/d0an01965h.","chicago":"Leppin, Christian, Astrid Peschel, Frederick Sebastian Meyer, Arne Langhoff, and Diethelm Johannsmann. “Kinetics of Viscoelasticity in the Electric Double Layer Following Steps in the Electrode Potential Studied by a Fast Electrochemical Quartz Crystal Microbalance (EQCM).” The Analyst 146, no. 7 (2021): 2160–71. https://doi.org/10.1039/d0an01965h.","apa":"Leppin, C., Peschel, A., Meyer, F. S., Langhoff, A., & Johannsmann, D. (2021). Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM). The Analyst, 146(7), 2160–2171. https://doi.org/10.1039/d0an01965h","bibtex":"@article{Leppin_Peschel_Meyer_Langhoff_Johannsmann_2021, title={Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM)}, volume={146}, DOI={10.1039/d0an01965h}, number={7}, journal={The Analyst}, publisher={Royal Society of Chemistry (RSC)}, author={Leppin, Christian and Peschel, Astrid and Meyer, Frederick Sebastian and Langhoff, Arne and Johannsmann, Diethelm}, year={2021}, pages={2160–2171} }","mla":"Leppin, Christian, et al. “Kinetics of Viscoelasticity in the Electric Double Layer Following Steps in the Electrode Potential Studied by a Fast Electrochemical Quartz Crystal Microbalance (EQCM).” The Analyst, vol. 146, no. 7, Royal Society of Chemistry (RSC), 2021, pp. 2160–71, doi:10.1039/d0an01965h.","short":"C. Leppin, A. Peschel, F.S. Meyer, A. Langhoff, D. Johannsmann, The Analyst 146 (2021) 2160–2171."},"page":"2160-2171","intvolume":" 146","year":"2021","author":[{"first_name":"Christian","last_name":"Leppin","full_name":"Leppin, Christian","id":"117722"},{"first_name":"Astrid","last_name":"Peschel","full_name":"Peschel, Astrid"},{"last_name":"Meyer","full_name":"Meyer, Frederick Sebastian","first_name":"Frederick Sebastian"},{"last_name":"Langhoff","full_name":"Langhoff, Arne","first_name":"Arne"},{"last_name":"Johannsmann","full_name":"Johannsmann, Diethelm","first_name":"Diethelm"}],"date_created":"2025-12-18T17:27:56Z","volume":146,"publisher":"Royal Society of Chemistry (RSC)","date_updated":"2025-12-18T17:34:42Z","doi":"10.1039/d0an01965h","title":"Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM)"},{"language":[{"iso":"eng"}],"abstract":[{"lang":"eng","text":"A quartz crystal microbalance (QCM) is described, which simultaneously determines resonance frequency and bandwidth on four different overtones. The time resolution is 10 milliseconds. This fast, multi-overtone QCM is based on multi-frequency lockin amplification. Synchronous interrogation of overtones is needed, when the sample changes quickly and when information on the sample is to be extracted from the comparison between overtones. The application example is thermal inkjet-printing. At impact, the resonance frequencies change over a time shorter than 10 milliseconds. There is a further increase in the contact area, evidenced by an increasing common prefactor to the shifts in frequency, Δf, and half-bandwidth, ΔΓ. The ratio ΔΓ/(−Δf), which quantifies the energy dissipated per time and unit area, decreases with time. Often, there is a fast initial decrease, lasting for about 100 milliseconds, followed by a slower decrease, persisting over the entire drying time (a few seconds). Fitting the overtone dependence of Δf(n) and ΔΓ(n) with power laws, one finds power-law exponents of about 1/2, characteristic of semi-infinite Newtonian liquids. The power-law exponents corresponding to Δf(n) slightly increase with time. The decrease of ΔΓ/(−Δf) and the increase of the exponents are explained by evaporation and formation of a solid film at the resonator surface."}],"publication":"Sensors","title":"A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing","date_created":"2025-12-18T17:29:29Z","publisher":"MDPI AG","year":"2020","issue":"20","quality_controlled":"1","extern":"1","article_number":"5915","user_id":"117722","_id":"63239","status":"public","type":"journal_article","doi":"10.3390/s20205915","author":[{"first_name":"Christian","last_name":"Leppin","full_name":"Leppin, Christian","id":"117722"},{"first_name":"Sven","last_name":"Hampel","full_name":"Hampel, Sven"},{"full_name":"Meyer, Frederick Sebastian","last_name":"Meyer","first_name":"Frederick Sebastian"},{"last_name":"Langhoff","full_name":"Langhoff, Arne","first_name":"Arne"},{"first_name":"Ursula Elisabeth Adriane","full_name":"Fittschen, Ursula Elisabeth Adriane","last_name":"Fittschen"},{"first_name":"Diethelm","last_name":"Johannsmann","full_name":"Johannsmann, Diethelm"}],"volume":20,"date_updated":"2025-12-18T17:33:50Z","citation":{"bibtex":"@article{Leppin_Hampel_Meyer_Langhoff_Fittschen_Johannsmann_2020, title={A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing}, volume={20}, DOI={10.3390/s20205915}, number={205915}, journal={Sensors}, publisher={MDPI AG}, author={Leppin, Christian and Hampel, Sven and Meyer, Frederick Sebastian and Langhoff, Arne and Fittschen, Ursula Elisabeth Adriane and Johannsmann, Diethelm}, year={2020} }","short":"C. Leppin, S. Hampel, F.S. Meyer, A. Langhoff, U.E.A. Fittschen, D. Johannsmann, Sensors 20 (2020).","mla":"Leppin, Christian, et al. “A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing.” Sensors, vol. 20, no. 20, 5915, MDPI AG, 2020, doi:10.3390/s20205915.","apa":"Leppin, C., Hampel, S., Meyer, F. S., Langhoff, A., Fittschen, U. E. A., & Johannsmann, D. (2020). A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing. Sensors, 20(20), Article 5915. https://doi.org/10.3390/s20205915","ama":"Leppin C, Hampel S, Meyer FS, Langhoff A, Fittschen UEA, Johannsmann D. A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing. Sensors. 2020;20(20). doi:10.3390/s20205915","ieee":"C. Leppin, S. Hampel, F. S. Meyer, A. Langhoff, U. E. A. Fittschen, and D. Johannsmann, “A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing,” Sensors, vol. 20, no. 20, Art. no. 5915, 2020, doi: 10.3390/s20205915.","chicago":"Leppin, Christian, Sven Hampel, Frederick Sebastian Meyer, Arne Langhoff, Ursula Elisabeth Adriane Fittschen, and Diethelm Johannsmann. “A Quartz Crystal Microbalance, Which Tracks Four Overtones in Parallel with a Time Resolution of 10 Milliseconds: Application to Inkjet Printing.” Sensors 20, no. 20 (2020). https://doi.org/10.3390/s20205915."},"intvolume":" 20","publication_status":"published","publication_identifier":{"issn":["1424-8220"]}}]