As a result of nonequilibrium forces, purely repulsive self-propelled particles undergo macrophase separation between a dense and a dilute phase. We present a thorough study of the ordering kinetics of such motility-induced phase separation (MIPS) in active Brownian particles in two dimensions, and we show that it is generically accompanied by microphase separation. The growth of the dense phase follows a law akin to the one of liquid-gas phase separation. However, it is made of a mosaic of hexatic microdomains whose size does not coarsen indefinitely, leaving behind a network of extended topological defects from which microscopic dilute bubbles arise. The characteristic length of these finite-size structures increases with activity, independently of the choice of initial conditions.
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http://dx.doi.org/10.1103/PhysRevLett.125.178004 | DOI Listing |
ACS Macro Lett
January 2025
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Poly(lactide) (PLA) is a promising biodegradable polymer with potential applications in single-use packaging. However, its use is limited by brittleness, and its biodegradability is restricted to industrial compost conditions due in part to an elevated glass transition temperature (). We previously showed that addition of a poly(ethylene-oxide)--poly(butylene oxide) diblock copolymer (PEO-PBO) forms macrophase-separated rubbery domains in PLA that can impart significant toughness at only 5 wt %.
View Article and Find Full Text PDFACS Nano
January 2025
Key Laboratory of Materials Chemistry for Energy Conversion and Storage of Ministry of Education (HUST), Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
Bicontinuous microparticles have advanced transport, mechanical, and electrochemical properties and show promising applications in energy storage, catalysis, and other fields. However, it remains a great challenge to fabricate bicontinuous microparticles of block copolymers (BCPs) by controlling the microphase separation due to the extremely narrow region of a bicontinuous structure in the phase diagram. Here, we demonstrate a strategy to balance the phase separation of BCPs and fluorinated additives at different length scales in emulsion droplets, providing a large window to access bicontinuous microparticles.
View Article and Find Full Text PDFNanoscale
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Langmuir
December 2024
Department of Applied Chemistry, Faculty of Engineering Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.
Hexagonal polymer plates of (sub)millimeter size that were uniform in shape and size were used as a stabilizer for emulsions, and the correlations of plate size, oil polarity, and plate dispersing media before emulsification with the formability, type, and droplet shape of emulsions were studied. The formability of the emulsions was improved by decreasing the plate size. The lower the oil polarity was, the more preferably O/W-type emulsions were formed, and as the oil polarity increased, the formability of W/O-type emulsions increased, whereas too high of an oil polarity resulted in no emulsion formation or macrophase separation of the oil dispersion of the plates and water.
View Article and Find Full Text PDFSmall
January 2025
School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, 44325, USA.
The distinct molecular states - single molecule, assembly, and aggregate - of two ionic macromolecules, TPPE-APOSS and TPE-APOSS, are easily distinguishable through their tunable fluorescence emission wavelengths, which reflect variations in intermolecular distances. Both ionic macromolecules contain aggregation-induced emission (AIE) active moieties whose emission wavelengths are directly correlated to their mutual distances in solution: far away from each other as individual molecules, maintaining a tunable and relatively long distance in electrostatic interactions-controlled blackberry-type assemblies (microphase separation), or approaching van der Waals close distance in aggregates (macrophase separation). Furthermore, within the blackberry assemblies, the emission wavelength decreases monotonically with increasing assembly size, indicative of shorter intermolecular distances at nanoscale.
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