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 -