We identify active phase separation as a generic demixing phenomenon in nonequilibrium systems with conservation constraints. Examples range from cell polarization to cell populations communicating via chemotaxis, and from self-propelled particle communities to mussels in ecology. We show that system-spanning properties of active phase separation in nonequilibrium systems near onset are described by the classical Cahn-Hilliard (CH) model. This result is rather surprising since the CH equation is famous as a model for phase separation at thermal equilibrium. We introduce a general reduction scheme to establish a unique mathematical link between the generic CH equation and system-specific models for active phase separation. This approach is exemplarily applied to a model for polarization of cells and a model for chemotactic cell communities. For cell polarization, we also estimate the validity range of the CH model.
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http://dx.doi.org/10.1103/PhysRevE.98.020603 | DOI Listing |
Macromol Rapid Commun
January 2025
Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy and Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.
Simultaneous improvement in power conversion efficiency (PCE) and device stability is very important for organic solar cells (OSCs). Herein, oligothiophene-based polymer W19 with excellent solvent resistance is exploited as a polymer thin layer to optimize the active layer morphology and then device efficiency and stability. Polymer W19 possesses a simple skeleton of trifluromethyl-substituted dithienoquinoxaline and quaterthiophene, whose thin layer shows suitable energy level, low surface energy, and strong interchain aggregation, leading to outstanding solvent resistance and excellent hole transport ability.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610213, P. R. China.
The self-assembly of macromolecular segments promotes the fabrication of polymer microspheres with multiple morphologies. Inspired by the xanthium shells, A dual-driven self-assembly method have defined that enables the construction of multi-dimensional morphologies on the microsphere surface at emulsion-confined interfaces. The two driving forces are derived from the phase separation caused by the immiscibility of macromolecular segments and the different interactions between chain segments of different hydrophilicity and water molecules.
View Article and Find Full Text PDFLangmuir
January 2025
Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Coacervation is generally treated as a liquid-liquid phase separation process and is controlled mainly by thermodynamics. However, kinetics could make a dominant contribution, especially in systems containing multiple interactions. In this work, using peptides of (XXLY)SSSGSS to tune the charge density and the degree of hydrophobicity, as well as to introduce secondary structures, we evaluated the effect of kinetics on biphasic coacervates formed by peptides with single-stranded oligonucleotides and quaternized dextran at varying pH values.
View Article and Find Full Text PDFDalton Trans
January 2025
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, P.R. China.
Photocatalytic degradation of the azo dye orange II using NdVO/VO/BiVO under visible light is reported here, and this oxygen-rich defect three-phase heterojunction structure is constructed using a two-step cation exchange method. This heterojunction significantly enhances the separation and migration efficiency of photo-induced charges, while the accompanying oxygen defects effectively capture photogenerated electrons, thereby suppressing the recombination of electrons and holes. Experimental characterization and theoretical calculations demonstrate the efficient separation and transfer capabilities of photogenerated carriers and their excellent photocatalytic degradation performance.
View Article and Find Full Text PDFJ Chromatogr A
January 2025
School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, PR China. Electronic address:
Evodiamine, a chiral quinazoline alkaloid in the traditional Chinese medicine Evodiae fructus, exhibited efficacy for CNS diseases. In this study, the pure enantiomers of evodiamine were prepared in large quantities via chemical resolution. Their structures were elucidated by MS, NMR and ECD.
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