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We investigated the temperature-dependent structural evolution of thermoreversible triblock terpolypeptoid hydrogels, namely poly(N-allyl glycine)-b-poly(N-methyl glycine)-b-poly(N-decyl glycine) (AMD), using small-angle neutron scattering (SANS) with contrast matching in conjunction with X-ray scattering and cryogenic transmission electron microscopy (cryo-TEM) techniques. At room temperature, A100M101D10 triblock terpolypeptoids self-assemble into core-corona-type spherical micelles in aqueous solution. Upon heating above the critical gelation temperature (T gel), SANS analysis revealed the formation of a two-compartment hydrogel network comprising distinct micellar cores composed of dehydrated A blocks and hydrophobic D blocks. At T ≳ T gel, the temperature-dependent dehydration of A block further leads to the gradual rearrangement of both A and D domains, forming well-ordered micellar network at higher temperatures. For AMD polymers with either longer D block or shorter A block, such as A101M111D21 and A43M92D9, elongated nonspherical micelles with a crystalline D core were observed at T < T gel. Although these enlarged crystalline micelles still undergo a sharp sol-to-gel transition upon heating, the higher aggregation number of chains results in the immediate association of the micelles into ordered aggregates at the initial stage, followed by a disruption of the spatial ordering as the temperature further increases. On the other hand, fiber-like structures were also observed for AMD with longer A block, such as A153M127D10, due to the crystallization of A domains. This also influences the assembly pathway of the two-compartment network. Our findings emphasize the critical impact of initial micellar morphology on the structural evolution of AMD hydrogels during the sol-to-gel transition, providing valuable insights for the rational design of thermoresponsive hydrogels with tunable network structures at the nanometer scale.

Platinum-based materials exhibit a broad spectrum of biological activities, including antioxidant, anti-inflammatory, antimicrobial, and pro-collagen synthesis properties, making them particularly useful for various biomedical applications. This review summarizes the biological effects and therapeutic potential of platinum-based active ingredients in dermatological and skincare applications. We discuss their synthesis methods and their antioxidant, anti-inflammatory, antimicrobial, and collagen synthesis properties, which play essential roles in treating skin conditions including psoriasis and acne, as well as enhancing skin aesthetics in anti-aging products. Safety and sustainability concerns, including the need for green synthesis and comprehensive toxicological assessments to ensure safe topical applications, are also discussed. By providing an up-to-date overview of current research, we aim to highlight both the potential and the current challenges of platinum-based active ingredients in advancing dermatology and skincare solutions. [ABSTRACT FROM AUTHOR]

The microstructure and rheologicalproperties of micellar solutionsof Pluronic block copolymers (PEOx–PPOy–PEOx)in deuterated ethylammonium nitrate (dEAN, a protic ionic liquid)are studied by small- and ultrasmall-angle neutron scattering (SANSand USANS), fluorescence microscopy, and shear rheology. A homologousseries of three Pluronics with similar PPO block length (F127 (PEO106–PPO70–PEO106), P123(PEO20–PPO70–PEO20),and L121 (PEO5–PPO70–PEO5)) are examined to explore the effect of the relative balance ofsolvophilic to solvophobic block size on the self-assembled microstructure.Both F127 and P123 form spherical micelles in dEAN that assemble intoface-centered and body-centered cubic supramolecular crystals, respectively,upon increasing concentration or temperature. The transition fromdisordered to crystalline (ordered) structures manifests as a sol–gelrheological transition. A richer phase diagram is observed in theL121/dEAN system: due to its low solvophilicity in dEAN, L121 self-assemblesinto structures with low curvatures, namely, vesicles in the diluteregime, elongated (wormlike) micelles at intermediate concentrationsand low temperatures, a nematic phase in concentrated solutions, andmultilamellar phases at high temperatures. Highly viscoelastic solutionsare created by the self-assembly of entangled L121 wormlike micelles.Structural length scales of the three Pluronic/dEAN systems in thevarious mesophases are determined from SANS and USANS. [ABSTRACT FROM AUTHOR]