Article
Chemistry, Physical
Dominik Schaefer, Maximilian Kohns, Hans Hasse
Summary: A set of molecular models for alkali nitrates in aqueous solutions was developed and used to predict their thermophysical properties through molecular dynamics simulations. The models combined a nitrate anion model from literature with alkali cation models previously developed by the researchers. The SPC/E water model and Lorentz-Berthelot combining rules were applied to describe the interactions. The results showed that the models accurately predicted properties such as density, water activity, mean ionic activity coefficient, self-diffusion coefficients, and radial distribution functions of the studied solutions.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Xiangwen Wang, Simon L. Clegg, Devis Di Tommaso
Summary: In this study, atomistic simulations were used to determine the parameters of thermodynamic hydration models. A cooperative hydration model was implemented to categorize water molecules in electrolyte solutions into different subpopulations. By reparameterizing the models with the computed values of the parameters, the osmotic coefficients of MgCl2 solutions consistent with measurements were obtained.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Alice J. Hutchinson, Juan F. Torres, Ben Corry
Summary: This study aims to improve the accuracy of MD thermodiffusion models by assessing different water models in recreating thermodiffusion in aqueous NaCl solutions. By comparing the modeled parameters to experimental values, TIP3P-FB is determined to be the best water model.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Tasneem Ottallah, Sophia A. Parandian, Steven W. Rick
Summary: Two different potentials, the modified TraPPE-UA model and the modified GAFF model, are tested for temperature-dependent properties of PEO, with the TraPPE-UA model found to be more accurate in reproducing experimental properties.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Polymer Science
Wesley Michaels, Yan Zhao, Jian Qin
Summary: The study developed all-atom force fields for undoped and highly doped PEDOT systems, which showed significant improvements in simulating molecular structures and properties compared to GAFF. Meaningful differences were identified between undoped and highly doped PEDOT, with the optimized force fields capturing the finite size of charge carriers in doped PEDOT models.
Article
Chemistry, Analytical
Atsushi Miura, Riku Nohara, Azumi Nojima, Noboru Kitamura
Summary: This study reports the photothermal phase separation of aqueous PNIPAM/BuOH solutions using focused 1064 nm laser, resulting in the formation of single microparticles for the simultaneous extraction and detection of single RhB molecules. This method shows potential for micrometer-scale extraction and analysis of individual molecules in similar solutions.
ANALYTICAL CHEMISTRY
(2021)
Article
Construction & Building Technology
Mohammad Javad Abdolhosseini Qomi, Laurent Brochard, Tulio Honorio, Ippei Maruyama, Matthieu Vandamme
Summary: Despite over a century of research, drying shrinkage still causes issues in concrete infrastructures due to a lack of understanding of its underlying mechanisms. Atomistic simulations hold promise in unlocking the mysteries of drying shrinkage at the nanoscale. The review discusses the progress and potential for atomistic simulations in understanding and addressing drying shrinkage in cementitious materials and other nanosystems.
CEMENT AND CONCRETE RESEARCH
(2021)
Article
Polymer Science
Chi Wang, Takeji Hashimoto, Ya-Chen Chuang, Keiji Tanaka, Yen-Pin Chang, Ting-Wei Yang, Meng-Tse Huang
Summary: This study investigates the phase transitions and gelation properties of aqueous solutions of atactic poly(N-isopropylacrylamide). The gel point and critical gel temperature were determined, and a phase diagram was constructed to describe the different phases of the solution. The structure and formation mechanism of gel junctions were also explored.
Article
Chemistry, Physical
B. P. Prajwal, James M. Blackwell, Patrick Theofanis, Fernando A. Escobedo
Summary: This work introduces a computational framework to study the molecular inhomogeneities in chemically amplified photoresists. Molecular dynamics simulations were used to investigate the effect of ionic and steric interactions on the dispersibility of photoacid generators (PAGs) in polymer medium. The results show that the dispersibility of PAGs varies depending on their ionic nature and the polymer used.
CHEMISTRY OF MATERIALS
(2023)
Article
Biochemistry & Molecular Biology
Daniel P. Erickson, Martha Dunbar, Elham Hamed, Oguz K. Ozturk, Osvaldo H. Campanella, Sinan Keten, Bruce R. Hamaker
Summary: The study revealed that specific peptide segments in corn protein variants tend to maintain stable aggregates and beta-sheet structures. Simulations showed that stability is influenced by the initial orientation and the presence of contiguous small hydrophobic residues. Peptide sequences without proline may have higher levels of beta-sheet structuring.
Article
Polymer Science
Chao Zhou, Chunda Ji, Yuchen Nie, Jingfa Yang, Jiang Zhao
Summary: This study provides single molecular evidence of cation binding to poly(ethylene oxide) (PEO) chains in aqueous solutions. The results show that the PEO chains are positively charged due to the binding of cations, and the addition of salt further increases the charging extent. The charging causes the chains to expand and increasing salt concentration leads to chain shrinkage, exhibiting a polyelectrolyte-like behavior.
Article
Materials Science, Multidisciplinary
Cong Dai, Nana Ofori-Opoku, Andrew Prudil, Michael Welland
Summary: Grain boundary engineering is an important strategy for enhancing the properties of polycrystalline metals. This study investigates twin grain boundary segregation and its effects on deformation behavior in alloy 800H. The simulations reveal that solute atoms tend to segregate at incoherent grain boundaries at high temperatures, leading to the formation of Shockley partial dislocations and deformation twins. These findings provide insights into the yielding behavior of alloy 800H and the application of grain boundary engineering in producing high-performance polycrystalline metallic materials.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Shujing Dong, Xiang-Yang Liu, Caizhi Zhou
Summary: This research explores the deformation mechanisms and interface misfit dislocation structures of B2-FeAl/Al nanolayered composites through atomistic simulations. It is found that there are two sets of dislocations in the interface misfit dislocation network, and the influence of layer thickness on uniaxial deformation response is investigated. The study also reveals differences in deformation behavior between weak Fe/Cu and strong FeAl/Al interfaces, with the latter triggering strain localization and void formation.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Chengkai Li, Zheyi Zhang, Haifei Zhan, Zhuoqun Zheng, Jingshuai Bai, Yuantong Gu
Summary: Low-dimensional carbon nanostructures, such as diamane, can effectively enhance the mechanical properties of polymer nanocomposites. Diamane with a laminated structure can promote the tensile properties of the nanocomposite by deforming simultaneously with the matrix, providing higher resistance under compression and shear tests. Surface functionalization for mechanical interlocking at the interface is effective for fully embedded nanofillers in enhancing the overall mechanical performance.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2021)
Article
Biotechnology & Applied Microbiology
Li Sun, Jierong Liang
Summary: This study presents a modeling study on the solubilities of hydrogen sulfide in water and aqueous sodium salt solutions, proving that the electrolyte version of the equation of state model can accurately calculate the solubilities over wide ranges of temperature, pressure, and salt molality, which is crucial for gas exploitation and geological storage.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2023)
Article
Engineering, Chemical
Gangqiang Yu, Nicolas F. Gajardo-Parra, Min Chen, Biaohua Chen, Gabriele Sadowski, Christoph Held
Summary: The suitability of phenyl-based deep eutectic solvents (DESs) as absorbents for toluene absorption was investigated using thermodynamic modeling and molecular dynamics (MD). The thermodynamic models PC-SAFT and COSMO-RS were used to predict the vapor-liquid equilibrium of DES-toluene systems. Among the DESs studied, [TEBAC][PhOH] consisting of TEBAC and PhOH was found to be the most suitable absorbent based on its thermodynamic characteristics and molecular-level interactions. This work provides guidance for designing efficient DESs for the absorption of aromatic volatile organic compounds.
Article
Thermodynamics
Jonas Habicht, Christoph Brandenbusch, Gabriele Sadowski
Summary: In this study, a machine learning approach based on deep neural networks was developed to predict PC-SAFT pure-component parameters for non-associating molecules. The use of extended-connectivity fingerprints as input and optimization of bit collisions improved the accuracy of predictions. The results were validated by comparing calculated physical properties to experimental data. This predictive machine learning approach can be used in early process synthesis.
FLUID PHASE EQUILIBRIA
(2023)
Article
Medicine, Research & Experimental
Peter Kroll, Lara Exner, Christoph Brandenbusch, Gabriele Sadowski
Summary: Up to 90% of newly developed APIs are poorly water soluble and have low oral bioavailability. Surfactants are promising excipients to improve solubility and bioavailability. This study investigated the influence of hydrophobic and hydrophilic chain lengths of CiEj surfactants on the solubilization of fenofibrate, naproxen, and lidocaine. The results provide valuable insights into the solubilization mechanisms of APIs in surfactant aggregates.
MOLECULAR PHARMACEUTICS
(2023)
Article
Chemistry, Multidisciplinary
Tim van Lingen, Valentina Bragoni, Marco Dyga, Benjamin Exner, Daniel Schick, Christoph Held, Gabriele Sadowski, Lukas J. Goossen
Summary: This study addresses the challenge of salt waste formation in C-H carboxylations, which hinders the use of CO2 as a C-1 building block in industrial synthesis. Through a circular process, dimethyl succinate, a C-4 base chemical, is produced from CO2 and acetylene. Increased CO2 pressure allows for reversible acidification and esterification of the succinate salt, while the cesium base and hydrogenation catalyst are regenerated for reuse. Thermodynamic modeling reveals the origins of the reversible acidity switch and the crucial roles of the cesium base and NMP/MeOH solvents.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Biochemical Research Methods
Lisa Janssen, Gabriele Sadowski, Christoph Brandenbusch
Summary: The main challenge in implementing highly efficient multi-phase whole-cell biocatalytic processes industrially is the formation of stable Pickering-type emulsions, which hinders downstream processing. By using the phenomenon of catastrophic phase inversion (CPI), efficient phase separation can be achieved within minutes. To demonstrate the applicability of CPI as an innovative process step, a fully automated lab-scale prototype was designed and constructed. The knowledge of the CPI point is crucial for successfully destabilizing the inverted state of emulsion.
BIOTECHNOLOGY JOURNAL
(2023)
Article
Chemistry, Physical
Johanna Busch, David Kotwica, Loai Al Sheakh, Thomas Headen, Tristan G. A. Youngs, Dietmar Paschek, Ralf Ludwig
Summary: Hydrogen bonding, which plays a crucial role in various fields, is 100 years old. In this study, the hydrogen bonding in mixtures of a hydroxyl-functionalized ionic liquid and an H-bond-accepting molecular liquid is investigated through experiments and simulations. The different strengths and distributions of the hydrogen bonds in the mixture have the potential to provide solvents with applications in H-bond-related chemistry.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Alexander E. Khudozhitkov, Dietmar Paschek, Alexander G. Stepanov, Daniil I. . Kolokolov, Ralf Ludwig
Summary: Recent research has shown that cationic cluster formation not only changes the local structures of ionic liquids but also influences the dynamics of cations in a characteristic way. Solid-state 2H NMR spectroscopy is suitable for studying molecular motion even when the hydrogen bonded species of interest are indistinguishable due to fast deuteron exchange. It also provides valuable information about the applicability of well-accepted relaxation models.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Medicine, Research & Experimental
Birte Gronniger, Espen Fritschka, Ineke Fahrig, Andreas Danzer, Gabriele Sadowski
Summary: Polymers such as PVPVA and HPMCAS are commonly used to enhance the bioavailability of APIs by serving as a matrix for ASDs. The water sorption in the ASDs is influenced by the surrounding air. In this study, water sorption in different materials was measured and predicted using various theoretical approaches, providing important information about water diffusion coefficients in ASDs.
MOLECULAR PHARMACEUTICS
(2023)
Article
Medicine, Research & Experimental
Birte Groenniger, Andreas Danzer, Kristof Kimpe, Abhishek Singh, Gabriele Sadowski
Summary: Amorphous solid dispersions (ASDs) are commonly used to enhance the dissolution rate of poorly soluble active pharmaceutical ingredients (APIs). However, most ASDs tend to crystallize eventually due to thermodynamic instability. The crystallization kinetics of ASDs depend on the thermodynamic driving force and molecular mobility, which are affected by factors such as drug load, temperature, and relative humidity (RH). This study focuses on viscosity as an indicator of molecular mobility in ASDs.
MOLECULAR PHARMACEUTICS
(2023)
Article
Biochemistry & Molecular Biology
Moreno Ascani, Gabriele Sadowski, Christoph Held
Summary: In this study, an algorithm was implemented in the PC-SAFT framework to predict the thermodynamic equilibrium behavior of two multicomponent esterification systems. The results showed that PC-SAFT could accurately predict the chemical equilibrium composition and liquid-liquid phase behavior of the systems. This study highlights the potential of a physical sound model for thermodynamic-based modeling of chemical reacting systems undergoing liquid-liquid phase separation.
Article
Pharmacology & Pharmacy
Adrian Krummnow, Andreas Danzer, Kristin Voges, Samuel O. O. Kyeremateng, Matthias Degenhardt, Gabriele Sadowski
Summary: The poor bioavailability of an API can be improved by dissolving it in a polymeric matrix through the formation of an amorphous solid dispersion (ASD). Crystallization and amorphous phase separation of the API can decrease its bioavailability. This study quantified the kinetics of water-induced amorphous phase separation in RIT/PVPVA ASDs and determined the compositions of the evolving amorphous phases using confocal Raman spectroscopy.
Article
Biochemistry & Molecular Biology
Fatima Anjum, Maximilian Wessner, Gabriele Sadowski
Summary: Membrane-based diafiltration was used to remove ethanol from the API crystal suspension, reducing the solvent concentration below the specified limit. The size and form of the crystals remained unchanged during the solvent exchange process. This work is significant for bottom-up API production and provides a foundation for further experimental design in solvent exchange processes.
Article
Thermodynamics
Daniel Schick, Qiaoyun Chen, Lennart Hellfajer, Alexander Strangmann, Paul Figiel, J. P. Martin Trusler, Gabriele Sadowski, Christoph Held
Summary: In this study, the CO2 solubility in solvent mixtures containing NMP and water with additional electrolytes was predicted using the ePC-SAFT advanced model, and the predictions matched well with the experimental data. It was found that NMP increased the CO2 solubility while electrolytes caused a salting-out effect on the CO2 solubility. The influence of CO2, NMP, and electrolytes on the kinetics and equilibrium of the esterification reaction was also investigated, with CO2 and NMP showing a negative effect on the kinetics and NMP having a negative influence on the equilibrium.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2023)
Article
Chemistry, Physical
Johanna Busch, Dietmar Paschek
Summary: Recently, an analytical expression for the system size dependence and direction-dependence of self-diffusion coefficients for neat liquids has been derived for molecular dynamics simulations. This expression allows for the determination of the true self-diffusion coefficient and viscosity using a specific box geometry.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Pharmacology & Pharmacy
Kai Ge, Raphael Paus, Vera Penner, Gabriele Sadowski, Yuanhui Ji
Summary: The influence mechanism of biorelevant media on the dissolution of active pharmaceutical ingredients (APIs) was investigated. It was found that hexadecyl trimethyl ammonium bromide (CTAB) was superior to sodium dodecyl sulfate (SDS) in promoting dissolution. High pH was favorable for the dissolution of acidic drugs, while high ionic strength benefited surface reactions.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2023)
