TY - JOUR AU - Odziomek, Mateusz AU - Giusto, Paolo AU - Kossmann, Janina AU - Tarakina, Nadezda V. AU - Heske, Julian Joachim AU - Rivadeneira, Salvador M. AU - Keil, Waldemar AU - Schmidt, Claudia AU - Mazzanti, Stefano AU - Savateev, Oleksandr AU - Perdigón‐Toro, Lorena AU - Neher, Dieter AU - Kühne, Thomas AU - Antonietti, Markus AU - López‐Salas, Nieves ID - 33687 IS - 40 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - “Red Carbon”: A Rediscovered Covalent Crystalline Semiconductor VL - 34 ER - TY - JOUR AB - The electrochemical properties of carbonaceous materials produced by hydrothermal carbonization, referred to as hydrochar, can be substantially improved by post-carbonization via pyrolysis. Although these materials have been widely studied for a variety of applications, the mechanisms underlying the pyrolysis are yet poorly understood. This study provides a comprehensive temperature-resolved characterization of the chemical composition, morphology and crystallinity of sucrose-derived hydrochar during pyrolysis. Thermogravimetric analysis, differential scanning calorimetry, and elemental analysis have shown that the dry hydrochar loses about 41% of its dry mass due to the exothermic disintegration of oxygen-containing groups until the carbonization is completed at about 850 °C with a total carbon yield of 93%. The carbonization and aromatization of the initially furanic and keto-aliphatic structure were analyzed by 13C solid-state nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The transition from an amorphous to a nanocrystalline graphitic structure was analyzed using X-ray diffraction and Raman spectroscopy. The pore formation mechanism was examined by helium ion microscopy, transmission electron microscopy, and nitrogen adsorption measurements. The results indicate the formation of oxygen-rich nanoclusters up to 700 °C, which decompose up to 750 °C leaving behind equally sized pores, resulting in a surface area of up to 480 m2/g. AU - Wortmann, Martin AU - Keil, Waldemar AU - Brockhagen, Bennet AU - Biedinger, Jan AU - Westphal, Michael AU - Weinberger, Christian AU - Diestelhorst, Elise AU - Hachmann, Wiebke AU - Zhao, Yanjing AU - Tiemann, Michael AU - Reiss, Günter AU - Hüsgen, Bruno AU - Schmidt, Claudia AU - Sattler, Klaus AU - Frese, Natalie ID - 29376 JF - Journal of Analytical and Applied Pyrolysis KW - Analytical Chemistry KW - Fuel Technology SN - 0165-2370 TI - Pyrolysis of sucrose-derived hydrochar VL - 161 ER - TY - JOUR AU - Wortmann, Martin AU - Viertel, Klaus AU - Welle, Alexander AU - Keil, Waldemar AU - Frese, Natalie AU - Hachmann, Wiebke AU - Krieger, Philipp AU - Brikmann, Johannes AU - Schmidt, Claudia AU - Moritzer, Elmar AU - Hüsgen, Bruno ID - 35327 JF - International Journal of Heat and Mass Transfer KW - Fluid Flow and Transfer Processes KW - Mechanical Engineering KW - Condensed Matter Physics SN - 0017-9310 TI - Anomalous bulk diffusion of methylene diphenyl diisocyanate in silicone elastomer VL - 177 ER - TY - JOUR AB - Thermostable compartmentalized sodium-water sites through intercalated γ-aminopropyl-dimethyl-ethoxy silane in synthetic hectorite. AU - Keil, Waldemar AU - Zhao, Kai AU - Oswald, Arthur AU - Bremser, Wolfgang AU - Schmidt, Claudia AU - Hintze-Bruening, Horst ID - 35326 IS - 1 JF - Physical Chemistry Chemical Physics KW - Physical and Theoretical Chemistry KW - General Physics and Astronomy SN - 1463-9076 TI - Thermostable water reservoirs in the interlayer space of a sodium hectorite clay through the intercalation of γ-aminopropyl(dimethyl)ethoxysilane in toluene VL - 24 ER - TY - JOUR AU - Wortmann, Martin AU - Frese, Natalie AU - Keil, Waldemar AU - Brikmann, Johannes AU - Biedinger, Jan AU - Brockhagen, Bennet AU - Reiss, Günter AU - Schmidt, Claudia AU - Gölzhäuser, Armin AU - Moritzer, Elmar AU - Hüsgen, Bruno ID - 35328 IS - 11 JF - ACS Applied Polymer Materials KW - Organic Chemistry KW - Polymers and Plastics KW - Process Chemistry and Technology SN - 2637-6105 TI - The Deterioration Mechanism of Silicone Molds in Polyurethane Vacuum Casting VL - 2 ER - TY - JOUR AB - Thermally stabilized and subsequently carbonized nanofibers are a promising material for many technical applications in fields such as tissue engineering or energy storage. They can be obtained from a variety of different polymer precursors via electrospinning. While some methods have been tested for post-carbonization doping of nanofibers with the desired ingredients, very little is known about carbonization of blend nanofibers from two or more polymeric precursors. In this paper, we report on the preparation, thermal treatment and resulting properties of poly(acrylonitrile) (PAN)/poly(vinylidene fluoride) (PVDF) blend nanofibers produced by wire-based electrospinning of binary polymer solutions. Using a wide variety of spectroscopic, microscopic and thermal characterization methods, the chemical and morphological transition during oxidative stabilization (280 °C) and incipient carbonization (500 °C) was thoroughly investigated. Both PAN and PVDF precursor polymers were detected and analyzed qualitatively and quantitatively during all stages of thermal treatment. Compared to pure PAN nanofibers, the blend nanofibers showed increased fiber diameters, strong reduction of undesired morphological changes during oxidative stabilization and increased conductivity after carbonization. AU - Wortmann, Martin AU - Frese, Natalie AU - Mamun, Al AU - Trabelsi, Marah AU - Keil, Waldemar AU - Büker, Björn AU - Javed, Ali AU - Tiemann, Michael AU - Moritzer, Elmar AU - Ehrmann, Andrea AU - Hütten, Andreas AU - Schmidt, Claudia AU - Gölzhäuser, Armin AU - Hüsgen, Bruno AU - Sabantina, Lilia ID - 25901 JF - Nanomaterials SN - 2079-4991 TI - Chemical and Morphological Transition of Poly(acrylonitrile)/Poly(vinylidene Fluoride) Blend Nanofibers during Oxidative Stabilization and Incipient Carbonization ER - TY - JOUR AB - The Haller relationship was applied to estimate the nematic order parameter S from 1H NMR spectra of fully protonated liquid crystals aligned in the magnetic field. The NMR line shapes were approximated as doublets of very broad peaks. Both the temperature-dependent doublet Splitting and the full width at half maximum of the whole spectra were used for Haller extrapolation. The order parameters obtained with the proposed approach for 4-cyano-4'-pentylbiphenyl (5CB) and the nematic mixture E7 were found to be in good agreement with previously reports. AU - Tang, Ming-xue AU - Schmidt, Claudia ID - 35398 JF - Chinese Journal of Magnetic Resonance KW - nematic liquid crystal KW - order parameter KW - Haller analysis KW - 1H NMR TI - Estimation of Nematic Order Parameters via Haller Analysis of 1H NMR Spectra of Liquid Crystals VL - 36 ER - TY - JOUR AB - The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean–Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed. AU - Weinberger, Christian AU - Heckel, Tatjana AU - Schnippering, Patrick AU - Schmitz, Markus AU - Guo, Anpeng AU - Keil, Waldemar AU - Marsmann, Heinrich C. AU - Schmidt, Claudia AU - Tiemann, Michael AU - Wilhelm, René ID - 25907 JF - Nanomaterials SN - 2079-4991 TI - Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction ER - TY - JOUR AU - Kuczera, Stefan AU - Gentile, Luigi AU - Brox, Timothy I. AU - Olsson, Ulf AU - Schmidt, Claudia AU - Galvosas, Petrik ID - 5971 IS - 28 JF - Langmuir SN - 0743-7463 TI - Multilamellar Vesicle Formation Probed by Rheo-NMR and Rheo-SALS under Large Amplitude Oscillatory Shear VL - 34 ER - TY - JOUR AB - Gelled lyotropic liquid crystals can be formed by adding a gelator to a mixture of surfactant and solvent. If the gel network and the liquid-crystalline phase coexist without influencing each other, the self-assembly is called orthogonal. In this study, the influence of the organogelator 12-hydroxyoctadecanoic acid (12-HOA) on the lamellar and hexagonal liquid crystalline phases of the binary system H2O–C12E7 (heptaethylene glycol monododecyl ether) is investigated. More precisely, we added 12-HOA at mass fractions from 0.015 to 0.05 and studied the resulting phase diagram of the system H2O–C12E7 by visual observation of birefringence and by 2H NMR spectroscopy. In addition, the dynamic shear moduli of the samples were measured in order to examine their gel character. The results show that 12-HOA is partly acting as co-surfactant, manifested by the destabilization of the hexagonal phase and the stabilization of the lamellar phase. The higher the total surfactant concentration, the more 12-HOA is incorporated in the surfactant layer. Accordingly, its gelation capacity is substantially reduced in the surfactant solution compared to the system 12-HOA–n-decane, and large amounts of gelator are required for gels to form, especially in the lamellar phase. AU - Steck, Katja AU - Schmidt, Claudia AU - Stubenrauch, Cosima ID - 35330 IS - 3 JF - Gels KW - Polymers and Plastics KW - Organic Chemistry KW - Biomaterials KW - Bioengineering SN - 2310-2861 TI - The Twofold Role of 12-Hydroxyoctadecanoic Acid (12-HOA) in a Ternary Water—Surfactant—12-HOA System: Gelator and Co-Surfactant VL - 4 ER - TY - JOUR AU - Schmidt, Claudia AU - Bühler, J. AU - Heinrich, A.-C. AU - Allerbeck, J. AU - Podzimski, R. AU - Berghoff, Daniel AU - Meier, Torsten AU - Schmidt, Wolf Gero AU - Reichl, C. AU - Wegscheider, W. AU - Brida, D. AU - Leitenstorfer, A. ID - 10018 JF - Nature Communications SN - 2041-1723 TI - Signatures of transient Wannier-Stark localization in bulk gallium arsenide VL - 9 ER - TY - JOUR AU - Xu, Yang AU - Laupheimer, Michaela AU - Preisig, Natalie AU - Sottmann, Thomas AU - Schmidt, Claudia AU - Stubenrauch, Cosima ID - 35332 IS - 31 JF - Langmuir KW - Electrochemistry KW - Spectroscopy KW - Surfaces and Interfaces KW - Condensed Matter Physics KW - General Materials Science SN - 0743-7463 TI - Gelled Lyotropic Liquid Crystals VL - 31 ER - TY - CHAP AU - Grewe, Felix AU - Ortmeyer, Jochen AU - Haase, Roxana AU - Schmidt, Claudia ID - 35331 SN - 9783319151281 T2 - Colloid Process Engineering TI - Colloidal Gels Formed by Dilute Aqueous Dispersions of Surfactant and Fatty Alcohol ER - TY - GEN AU - Schmidt, Claudia ID - 35333 TI - Rheo-nuclear magnetic resonance spectroscopy VL - Vol. 26 Issue 6 ER - TY - JOUR AB - Abstract Flow fields and shear-induced structures in the lamellar (L α ) phase of the system triethylene glycol mono n-decyl ether (C10E3)/water were investigated by NMR velocimetry, diffusometry, and 2 H NMR spectroscopy. The transformation from multilamellar vesicles (MLVs) to aligned planar lamellae is accompanied by a transient gradient shear banding. A high-shear-rate band of aligned lamellae forms next to the moving inner wall of the cylindrical Couette shear cell while a low-shear-rate band of the initial MLV structure remains close to the outer stationary wall. The band of layers grows at the expense of the band of MLVs until the transformation is completed. This process scales with the applied strain. Wall slip is a characteristic of the MLV state, while aligned layers show no deviation from Newtonian flow. The homogeneous nature of the opposite transformation from well aligned layers to MLVs via an intermediate structure resembling undulated multilamellar cylinders is confirmed. The strain dependence of this transformation appears to be independent of temperature. The shear diagram, which represents the shear-induced structures as a function of temperature and shear rate, contains a transition region between stable layers and stable MLVs. The steady-state structures in the transition region show a continuous change from layer-like at high temperature to MLV-like at lower temperature. These structures are homogeneous on a length scale above a few micrometers. AU - Medronho, Bruno AU - Olsson, Ulf AU - Schmidt, Claudia AU - Galvosas, Petrik ID - 35341 IS - 11-12 JF - Zeitschrift für Physikalische Chemie KW - Physical and Theoretical Chemistry SN - 2196-7156 TI - Transient and Steady-State Shear Banding in a Lamellar Phase as Studied by Rheo-NMR VL - 226 ER - TY - JOUR AU - Quiñones, Javier Pérez AU - Gothelf, Kurt V. AU - Kjems, Jørgen AU - Heras, Angeles AU - Schmidt, Claudia AU - Peniche, Carlos ID - 35336 IS - 1 JF - Journal of Biomaterials and Tissue Engineering KW - Biomedical Engineering KW - Medicine (miscellaneous) KW - Bioengineering KW - Biotechnology SN - 2157-9083 TI - Novel Self-Assembled Nanoparticles of Testosterone-Modified Glycol Chitosan and Fructose Chitosan for Controlled Release VL - 3 ER - TY - JOUR AU - Bilalov, Azat AU - Elsing, Jonas AU - Haas, Eva AU - Schmidt, Claudia AU - Olsson, Ulf ID - 35334 JF - Journal of Colloid and Interface Science KW - Colloid and Surface Chemistry KW - Surfaces KW - Coatings and Films KW - Biomaterials KW - Electronic KW - Optical and Magnetic Materials SN - 0021-9797 TI - Embedding DNA in surfactant mesophases: The phase diagram of the ternary system dodecyltrimethylammonium–DNA/monoolein/water in comparison to the DNA-free analogue VL - 394 ER - TY - JOUR AU - Stubenrauch, Cosima AU - Kleinschmidt, Felix AU - Schmidt, Claudia ID - 35340 IS - 25 JF - Langmuir KW - Electrochemistry KW - Spectroscopy KW - Surfaces and Interfaces KW - Condensed Matter Physics KW - General Materials Science SN - 0743-7463 TI - Structural Evolution in the Isotropic Channel of a Water–Nonionic Surfactant System That Has a Disconnected Lamellar Phase: A 1H NMR Self-Diffusion Study VL - 28 ER - TY - JOUR AU - Quiñones, Javier Pérez AU - Gothelf, Kurt Vesterager AU - Kjems, Jørgen AU - Caballero, Ángeles María Heras AU - Schmidt, Claudia AU - Covas, Carlos Peniche ID - 35335 IS - 1 JF - Carbohydrate Polymers KW - Materials Chemistry KW - Polymers and Plastics KW - Organic Chemistry SN - 0144-8617 TI - N,O6-partially acetylated chitosan nanoparticles hydrophobically-modified for controlled release of steroids and vitamin E VL - 91 ER - TY - JOUR AU - Quiñones, Javier Pérez AU - Gothelf, Kurt Vesterager AU - Kjems, Jørgen AU - Caballero, Ángeles María Heras AU - Schmidt, Claudia AU - Covas, Carlos Peniche ID - 35339 IS - 4 JF - Carbohydrate Polymers KW - Materials Chemistry KW - Polymers and Plastics KW - Organic Chemistry SN - 0144-8617 TI - Self-assembled nanoparticles of glycol chitosan – Ergocalciferol succinate conjugate, for controlled release VL - 88 ER -