The entropic effects in the comicellization behavior of amphiphilic AB copolymers differing in the chain size of solvophilic A parts were studied by means of molecular dynamics simulations. In particular, mixtures of miktoarm star copolymers differing in the molecular weight of solvophilic arms were investigated. We found that the critical micelle concentration values show a positive deviation from the analytical predictions of the molecular theory of comicellization for chemically identical copolymers. This can be attributed to the effective interactions between copolymers originated from the arm size asymmetry. The effective interactions induce a very small decrease in the aggregation number of preferential micelles triggering the nonrandom mixing between the solvophilic moieties in the corona. Additionally, in order to specify how the chain architecture affects the size distribution and the shape of mixed micelles we studied star-shaped, H-shaped, and homo-linked-rings-linear mixtures. In the first case the individual constituents form micelles with preferential and wide aggregation numbers and in the latter case the individual constituents form wormlike and spherical micelles.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevE.92.052601 | DOI Listing |
J Chem Theory Comput
January 2025
Department of Chemistry, University of Tromsø - The Arctic University of Norway, N9037 Tromsø, Norway.
In this review we discuss the development of methodology for calculating the temperature dependence and thermodynamic activation parameters for chemical reactions in solution and in enzymes, from computer simulations. We outline how this is done by combining the empirical valence bond method with molecular dynamics free energy simulations. In favorable cases it turns out that such simulations can even capture temperature optima for the catalytic rate.
View Article and Find Full Text PDFNeural Netw
January 2025
College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou, 310027, China. Electronic address:
Unsupervised domain adaptation (UDA) aims to annotate unlabeled target domain samples using transferable knowledge learned from the labeled source domain. Optimal transport (OT) is a widely adopted probability metric in transfer learning for quantifying domain discrepancy. However, many existing OT-based UDA methods usually employ an entropic regularization term to solve the OT optimization problem, inevitably resulting in a biased estimation of domain discrepancy.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
We derive an expression to determine the equilibrium probability distribution of a quantum state in contact with a noisy thermal environment that formally separates contributions from quantum and classical forms of probabilistic uncertainty. A statistical mechanical interpretation of this probability distribution enables us to derive an expression for the minimum free energy costs for arbitrary (reversible or irreversible) quantum state changes. Based on this derivation, we demonstrate that─in contrast to classical systems─the free energy required to erase or reset a qubit depends sensitively on both the fidelity of the target state and on the physical properties of the environment, such as the number of quantum bath states, due primarily to the entropic effects of system-bath entanglement.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan.
Control of the formation of liquid crystalline 3̄ gyroid phases and their nanostructures is critical to advance materials chemistry based on the structural feature of three-dimensional helical networks. Here, we present that introducing methyl side-group(s) and slight non-symmetry into aryloyl-hydrazine-based molecules is unexpectedly crucial for their formation and can be a new design strategy through tuning intermolecular interactions: the two chemical modifications in the core portion of the chain-core-chain type molecules effectively lower and extend the 3̄ phase temperature ranges with the increased twist angle between neighboring molecules along the network. The detailed analyses of the aggregation structure revealed the change in the core assembly mode from the double-layered core mode of the mother molecule (without methyl groups) to the single-layered core mode.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2024
Entropic Interface Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
Inspired by our recent success in designing CO-phobic and CO-philic domains on nano-MgO for effective CO adsorption, our ongoing efforts focus on incorporating dopants into pristine MgO to further enhance its CO adsorption capabilities. However, a clear set of guidelines for dopant selection and a holistic understanding of the underlying mechanisms is still lacking. In our investigation, we combined first-principles calculations with experimental approaches to explore the crystal and electronic structural changes in MgO doped with high-valence elements (Al, C, Si, and Ti) and their interactions with CO.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!