ACS Macro Letters最新文献

Reversible deactivation radical polymerization (RDRP) in an emulsion is a practical and environmentally friendly route to well-defined polymer synthesis. However, most emulsion RDRP has focused on conventional oil-in-water systems, restricting accessible materials to hydrophobic polymers. Here, we report the first example of a highly efficient and oxygen-tolerant inverse microemulsion and miniemulsion photoinduced ATRP (photoATRP) facilitated by a dual catalytic system. Irradiation with red light efficiently excites the photocatalyst methylene blue (MB⁺), facilitating the photoreduction of the deactivator to initiate and mediate polymerization. This process enables the precise synthesis of polymers with a controlled molecular weight, low dispersity (Đ ≤ 1.20), excellent chain-end fidelity, and temporal control. The versatility of this approach was further demonstrated by expanding the photocatalyst scope beyond MB⁺ to include a library of other water-soluble PC. This method was also successfully extended to the inverse miniemulsion. This work establishes a practical inverse emulsion photoATRP for synthesizing well-defined hydrophilic polymers.

Noncovalently cross-linked polymer materials are widely used due to their dynamic response, self-healing, recycling, and reprocessing capabilities. Among the noncovalent cross-linkers, photocontrolled cross-linking is of great interest due to its clean and noncontact process for forming and dissociating noncovalent polymer networks. However, most of the noncovalent cross-linkers rely on predetermined binding motifs that exhibit fixed association affinities, restricting their adaptability to diverse material properties. This work introduces a new strategy for photocontrolled noncovalent cross-linking based on photomodulated metal–ligand interactions. By employing interchangeable central cations, our system introduces a modular platform for tuning cross-linking strength, enabling property diversity without altering the underlying motif. As a result, we prepared materials that demonstrate a wide range of thermal and mechanical properties depending on the choice of central cation, expanding the potential for noncovalent polymer network materials and supporting their use in various applications.

Mixtures of polyethylene glycol (PEG) and dextran (Dex) represent a widely used class of aqueous two-phase systems (ATPS), with applications ranging from the purification of various biomolecules, such as nucleic acids, to the synthesis of protocells. A key feature underlying these applications is the selective accumulation of biomolecules within Dex-rich droplets in an aqueous PEG phase, but the physical origin of this partitioning remains unclear. Entropic interactions were long assumed to be the primary driving force; however, our systematic experiments using DNA of different lengths indicate that entropy alone cannot fully explain the observed behavior. We identify an additional and previously underappreciated contribution from electrostatic interactions: Dex carries a slightly more negative charge than PEG, which drives preferential cation accumulation in the Dex-rich phase. These counterions facilitate the selective partitioning of DNA inside the Dex-rich droplets. This mechanism explains the dependence of DNA uptake in Dex-rich droplets on the polymer length and salt concentration. Our findings establish that Donnan-type ion partitioning plays a crucial role in the localization of long nucleic acids in Dex-rich droplets, offering a unified explanation for this long-standing phenomenon. They lay the foundation for designing ATPS-based systems and help elucidate the physicochemical principles of biomolecular partition upon phase separation in cells.

Cyano-substituted oligo(p-phenylenevinylene) derivatives (cyano-OPVs) demonstrate superior photophysical properties in solution with photoluminescence quantum yield (PLQY) of up to 87% yet experience severe aggregation-caused quenching in the solid state (PLQY typically 20%–40%), fundamentally limiting their practical implementation in optoelectronic devices. Here, we present a novel approach to enhancing the solid-state PLQY of cyano-OPVs by harnessing polymer crystallization through supramolecular interactions. We designed and synthesized a 2-ureido-4[1H]-pyrimidinone (UPy)-functionalized cyano-OPV derivative (UPy-OPV-UPy) and incorporated it into a crystallizable UPy-terminated poly(butylene succinate) (PBS-UPy) matrix. Systematic investigation of the photophysical properties and isothermal crystallization kinetics of PBS-UPy/UPy-OPV-UPy blends revealed a remarkable solid-state PLQY of approximately 97%, surpassing both traditional solid-state fluorescent materials and solution-state performance. This unprecedented enhancement is attributed to the effect of crystallization-driven supramolecular reorganization, which disrupts unfavorable fluorophore aggregates. This nondestructive approach offers a new paradigm for designing high-performance solid-state emissive materials, potentially overcoming the persistent challenge of aggregation-caused quenching that typically limits solid-state fluorescent material performance.

Neoantigens are promising candidates for personalized cancer vaccines and immunotherapies. However, low immunogenicity and insufficient cross-presentation of neoantigens remain a major challenge. Inspired by natural glycocalyx and its important functions in immune response, here we report a glycocalyx-mimicking nanovehicle constructed from (oligo)mannoside-modified acid-sensitive glycopolymers to improve the efficiency of tumor neoantigens. These amphiphilic glycopolymers assembled into nanoparticles could serve as immune activators for dendritic cells maturation. The encapsulation of neoantigens in the glycopolymer nanocarrier improves the physicochemical properties and endosomal escape of the antigens, thereby not only enhancing their uptake and cross-presentation by dendritic cells but also promoting cytotoxic T cell proliferation and proinflammatory cytokine secretion. These results indicated that the glycocalyx-mimicking nanovehicle integrating delivery and immune adjuvant functions provides a promising platform for cancer vaccines.

Stimuli-responsive block copolymer (BCP) particles offer a promising platform for tunable photonic materials; however, most structural transformations originate from uniform lamellar templates that reorganize only under strong thermal or solvent-mediated activation. Here, we report a distinct pH-driven chain reorganization behavior in partially quaternized poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) microparticles that initially possess heterogeneous internal morphologies, comprising PS-encapsulated P2VP domains and stacked lamellar domains. Upon acid exposure, protonation of unquaternized P2VP establishes a hydration-induced swelling gradient: less-constrained lamellae laterally expand and redistribute along interfaces, whereas PS-encapsulated lamellar regions act as rigid anchors. This anisotropic response progressively redistributes chain stress and solvation, transforming the stacked lamellae into an irregular, laterally dilated morphology with thin, hydrated P2VP layers. This progressive chain reorganization gives rise to a steady blue-shift in structural color from 622 to 478 nm, in line with the gradual contraction of domain periodicity. These findings reveal that structural heterogeneity can serve as an intrinsic driving force for topological reconstruction in vitrified BCP particles, enabling programmable, history-dependent photonic responses under mild aqueous conditions.

Spider silk spinning begins with coacervation into a dense protein phase that organizes into liquid crystalline domains. Changes in salt concentration, together with shear forces, then direct the alignment needed to form highly ordered fibers. Inspired by this process, we developed a fully synthetic system of liquid crystalline complex coacervates designed to replicate the hierarchical organization and alignment mechanisms of spider silk, focusing on processing pathways. We show that salt concentration (tetrabutylammonium bromide, TBAB) governs the balance between isotropic and liquid crystalline states, with coacervation suppressed above 0.5 M, smectic order stabilized at ≤0.2 M, and isotropic chain networks prevailing at intermediate concentrations. Crucially, the degree of shear alignment depends strongly on salt: higher salt concentrations accelerate molecular relaxation and raise the threshold shear rate required to induce ordering, echoing the cooperative role of the ion composition and shear in natural silk spinning. Rheological and X-ray scattering measurements confirm that this salt–shear interplay dictates both the viscoelastic response and the molecular anisotropy. Finally, we demonstrate directional alignment through stretching and extrusion-based 3D printing and show that the unique tunability of salt concentration provides direct control over both processability and shear-induced alignment, offering a powerful biomimetic route to anisotropic material design.

Vinyl ketone polymers, including poly(phenyl vinyl ketone) and poly(p-chlorophenyl vinyl ketone), were successfully synthesized under light using atom transfer radical polymerization (ATRP). This marks the first successful attempt at ATRP of vinyl ketones. The polymerization kinetics revealed chain growth and maintained livingness, as further evidenced by successful chain extension using ethyl acrylate. The efficient main-chain cleavability of the polymers was confirmed under UV light. While the attainment of low dispersity remains an enduring challenge, this work offers promising potential for future success.

Accurate thiol quantification is essential for advancing thiol–X-ligation strategies in polymer and materials synthesis. Conventional assays, most notably Ellman’s test, are limited in scope, particularly for hydrophobic or multifunctional thiols. Here, we introduce a straightforward and broadly applicable ³¹P NMR spectroscopy method for thiol quantification, using 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (TMDP) as a phosphitylation reagent. The approach extends established ³¹P NMR protocols for hydroxyl and carboxyl group analysis to thiols, offering high specificity and stability in readout. The method demonstrates applicability across a wide range of substrates, from small organic molecules to polymeric multi thiols with M_n up to 8000 g·mol^–1. Comparative validation against Ellman’s assay and ¹H NMR spectroscopy reveals superior selectivity and resolution of the TMDP-based ³¹P NMR protocol, particularly for technical-grade thiols, where conventional methods fail to distinguish degradation products. This study establishes the TMDP-enabled ³¹P NMR as a reliable, information-rich tool for thiol quantification, giving simultaneously insights on hydroxy and carboxyl functionality patterns.

Soft colloids play a vital role in modern life and provide insights into the physics of vitrification. Soft colloidal glasses exhibit significant variations in dynamic fragility─the sensitivity of relaxation dynamics to concentrations. While particle softness, including cross-linking density and charge, influences fragility, their complex interplay obscures the fundamental physics. This study conducts a systematic investigation of 16 uncharged polystyrene soft nanoparticles (SNPs) with independently controlled diameter and elasticity. The research quantifies relaxation time as a function of particle concentration, diameter, and cross-linking density using two fitting parameters. Through this analysis, fragility is determined and correlated to the elastic energy per particle (particle elasticity multiplied by volume). Particles below a threshold elastic energy (smaller or softer) would deform readily under thermal energy, exhibiting strong glass behavior. In contrast, larger or stiffer particles undergo fragile glass transitions through a cooperative relaxation. This investigation establishes a dynamic phase diagram that predicts fragility transitions, addresses existing contradictions, and presents design principles for colloidal suspensions.