Thermally induced gelation in aqueous solutions of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) has been studied by rheological, optical microscopy, and turbidimetry measurements. The structural and mechanical properties of these hydrogels are dominated by the interplay between phase separation and gelation. In MC solutions, phase separation takes place almost simultaneously with gelation. An increase in the storage modulus is coupled to the appearance of a bicontinuous structure upon heating. However, a thermal gap exists between phase separation and gelation in the case of HPMC solutions. The storage modulus shows a dramatic decrease during phase separation and then rises in the subsequent gelation. A macroporous structure forms in the gels via "viscoelastic phase separation" linked to "double phase separation".
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http://dx.doi.org/10.1021/la300971r | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Department of Hydrogen and Renewable Energy, Kyungpook National University, Daegu 41566, Republic of Korea.
The side-chain directions in nonfullerene acceptors (NFAs) strongly influence the intermolecular interactions in NFAs; however, the influence of these side chains on the morphologies and charge carrier dynamics of Y6-based acceptors remains underexplored. In this study, we synthesize four distinct Y6-based acceptors, i.e.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Université de Mons, Laboratoire Interfaces & Fluides Complexes, 20 Place du Parc, B-7000 Mons, Belgium.
The phase separation that occurs in two-temperature mixtures, which are driven out of equilibrium at the local scale, has been thoroughly characterized, but much less is known about the depletion interactions that drive it. Using numerical simulations in dimension 2, we show that the depletion interactions extend beyond two particle diameters in dilute systems, as expected at equilibrium, and decay algebraically with an exponent -4. Solving for the N-particle distribution function in the stationary state, perturbatively in the interaction potential, we show that algebraic correlations with an exponent -2d arise from triplets of particles at different temperatures in spatial dimension d.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Hydrogel-based sensors typically demonstrate conspicuous swelling behavior in aqueous environments, which can severely compromise the mechanical integrity and distort sensing signals, thereby considerably constraining their widespread applicability. Drawing inspiration from the multilevel heterogeneous structures in biological tissues, an antiswelling hydrogel sensor endowed with high strength, rapid self-recovery, and low swelling ratio was fabricated through a water-induced phase separation and coordination cross-linking strategy. A dense heterogeneous architecture was developed by the integration of "rigid" quadridentate carboxyl-Zr coordination bonds and "soft" hydrophobic unit-rich regions featuring π-π stacking and cation-π interactions into the hydrogels.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States.
The nuclear pore complex (NPC) is the proteinous nanopore that solely regulates molecular transport between the nucleus and cytoplasm of a eukaryotic cell. Hypothetically, the NPC utilizes the hydrophobic barriers based on the repeats of phenylalanine-glycine (FG) units to selectively and efficiently transport macromolecules. Herein, we quantitatively assess the hydrophobicity of transport barriers confined in the nanopore by applying scanning electrochemical microscopy (SECM).
View Article and Find Full Text PDFProtein Sci
February 2025
Graduate School of Engineering, Osaka University, Osaka, Japan.
Amyloid fibril formation of α-synuclein (αSN) is a hallmark of synucleinopathies. Although the previous studies have provided numerous insights into the molecular basis of αSN amyloid formation, it remains unclear how αSN self-assembles into amyloid fibrils in vivo. Here, we show that αSN amyloid formation is accelerated in the presence of two macromolecular crowders, polyethylene glycol (PEG) (MW: ~10,000) and dextran (DEX) (MW: ~500,000), with a maximum at approximately 7% (w/v) PEG and 7% (w/v) DEX.
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