ACS Applied Polymer Materials最新文献

Significant advanceshave been made in recent years in the developmentof liquid resins for lithography-based 3D printing. Nevertheless,the incorporation of filler materials, including active and inactivenanoparticles, remains a major challenge due to issues related toresin stability, particle dispersion, and printability. Herein, wedemonstrate the key role of ionic liquids in stabilizing and homogenizingspin-crossover (SCO) particle-filled composite resins and investigatehow resin composition affects both the spin-crossover behavior andthe mechanical properties of 4D-printed structures fabricated by 405nm digital light processing (DLP). While the selected ionic liquiddoes not alter the intrinsic spin-crossover properties of the particles,the composition of the base resin, comprising phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) as photoinitiator, neopentyl glycol diacrylate(NPGDA) as cross-linker, and varying ratios of hydroxyethyl methacrylate(HEMA) and hydroxyethyl acrylate (HEA), significantly influences theparticles’ physicochemical environment and provides an effectivemeans to tune the mechanical performance of the printed architectures.These results highlight the potential of ionic liquid-based SCO compositeresins as promising platforms for the fabrication of responsive 4D-printeddevices.

The design of engineered living materials (ELMs) thatintegrateactive cells offers opportunities to create dynamic, adaptive systems.However, current methods often use bulk hydrogels that can immobilizecells and limit their growth and migration, which affects their overallfunctionality for use as an ELM. Here, we developed a granular hydrogelcomposite composed of hydrogel particles (i.e., microgels), Escherichia coli (E. coli), and a cross-linkable polymer that can be crosslinked with lightexposure when desired. We investigated the influence of matrix compositionand incubation conditions on microcolony morphology and mechanicalproperties and observed that the addition of microgels to the compositeresults in larger bacterial colonies with roughened morphologies andthat the granular hydrogel composite compressive modulus is dependenton the matrix composition and incubation conditions. To further demonstratethe potential of this system, we also showed that the granular hydrogelcomposites can be 3D printed into specified geometries, that the compositescan be used for sustained release of bacteria, and that the un-crosslinkedmatrix supports chemotactic migration, producing cell density gradientsthat can be fixed in place with crosslinking. Overall, the granularhydrogel composites provide an approach for the fabrication of ELMs.

Aluminum–air (Al–air) batteries are promisinghigh-energyelectrochemical storage systems, but the use of liquid alkaline electrolyteslimits their practical implementation because of leakage, poor mechanicalintegrity, and electrolyte management issues. Herein, we develop aflexible three-dimensional dual-network gel polymer electrolyte (GPE)comprising poly(vinyl alcohol) (PVA), hydroxyethyl cellulose (HEC),and potassium hydroxide (KOH), in which the PVA–HEC compositionand KOH concentration are systematically varied to regulate the porousnetwork, mechanical properties, and ionic transport. The optimizedG-2 formulation, containing equal amounts of PVA and HEC (2.5 g each)in 30 mL of 6 M KOH, forms a highly interconnected porous networkwith enhanced viscoelastic stability and electrolyte retention. Thebalanced PVA–HEC composition and higher KOH concentration resultin an ionic conductivity of 0.26 S cm^–1, substantiallyhigher than that of the other investigated formulations (0.13 and0.10 S cm^–1), while also providing favorable interfacialcharge-transfer characteristics. When integrated into a flexible Al–aircell with a Pt/C-coated Ni-foam air cathode, the G-2 electrolyte deliversa specific discharge capacity of 837.5 mA h g^–1 andan energy density of 670 ± 4.56 Wh kg^–1 at3 mA cm^–2. Furthermore, the cell maintains stablecharge–discharge operation for 52 cycles under the appliedcycling protocol. The combination of high ionic conductivity, mechanicallyrobust gel structure, electrolyte retention, and flexible cell integrationdemonstrates a practical strategy for replacing leakage-prone liquidelectrolytes in Al–air batteries. This work advances polymer-electrolyte-basedAl–air systems by demonstrating that compositional controlof a PVA–HEC dual-network can simultaneously address ionictransport and mechanical stability, providing a scalable platformfor flexible and leakage-resistant energy-storage devices.

Poly(3-hydroxybutyrate)(PHB) is a promising biodegradable polymer;however, its brittleness and narrow processing window limit broaderapplication. Here, a self-reinforcement strategy based on PHB copolymers─poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)─is developed to addressthese limitations. Core–shell electrospinning is used to fabricatebicomponent fibers with a PHBV core and a PHBH shell. The distinctmelting temperatures of the two copolymers enable selective softeningof the PHBH shell, while preserving the structural integrity of thePHBV core. Annealing induces interfiber coalescence and welding, forminginterconnected fiber junctions. Consequently, the annealed coaxialelectrospun fiber mats achieve an ultimate tensile strength (UTS)of 6.64 ± 0.24 MPa, which is not significantly different fromthat of neat PHBV fiber mats (6.41 ± 0.40 MPa; Welch’stwo-sample t-test, p = 0.30), whileexhibiting significantly higher toughness than neat PHBV fiber mats(125.33 ± 18 vs 45.18 ± 11 MJ m^–3; Welch’stwo-sample t-test, p < 0.001).DMA reveals that annealing increases the storage modulus from about609 to 1300 MPa while reducing the loss modulus from 332 to 121 MPa,indicating enhanced structural integrity and reduced molecular mobilitydue to interfiber coalescence. Oxygen permeability also decreasedfrom ∼3.8 ± 0.11×10^–20 to ∼2.9± 0.10 × 10^–20 m·Pa^–1·s^–1 following annealing, consistent withlower porosity and network densification. These findings demonstratethat a core–shell monomaterial design enables effective self-reinforcementwithout heterogeneous fillers, providing a design rationale for reducedformulation complexity relative to multicomponent systems containingdissimilar polymer chemistries or inorganic fillers.

The development of polyurethane elastomers with excellentcomprehensiveproperties, such as robust mechanical strength, high rebound resilience,fire retardancy, and aqueous degradability, is of great practicalsignificance. Herein, we report the design and synthesis of a polyurethaneelastomer exhibiting outstanding mechanical, thermal, and chemicalproperties, including high mechanical performance, intrinsic flameretardancy, strong adhesion capability, and aqueous and acid degradability.Specifically, a xylose-derived degradable chain extender (DHGX) anda P/N-containing reactive flame retardant (BHP) are rationally engineeredinto the polyurethane backbone to prepare the target elastomer (PU-DHGX-BHP).The as-prepared PU-DHGX-BHP exhibits a high tensile strength of 11.5MPa, together with a high elongation at break of 1018% and a hightoughness of 46.9 MJ m^–3. Moreover, PU-DHGX-BHPachieves a V-0 flammability rating and demonstrates self-extinguishingbehavior within 0.5 s. Owing to the dynamic hydrogen-bonding and π–πstacking interactions, PU-DHGX-BHP exhibits strong adhesion towardpolar substrates, with a high peel strength of 41.1 N cm^–1 on poly(vinyl chloride) (PVC) substrate. Furthermore, the incorporationof DHGX structures and urethane bonds into the polymer backbone enablesPU-DHGX-BHP to undergo complete degradation in acidic solutions andpartial degradation in aqueous environments, with xylose and glyoxylicacid recovered as degradation products. This study provides a feasiblestrategy for the development of degradable polyurethane elastomersderived from non-edible biomass sugars, opening avenues for the designof next-generation sustainable elastomers.

This study introducesa versatile method for fabricatingcross-linked,hierarchically ordered multilayer nanostructures from PS-b-P4VP block copolymer (BCP) films. The approach combines supramolecularhydrogen bonding of cinnamic acid selective to the P4VP block, followedby UV-induced photocycloaddition to form truxillic acid cross-links.Efficient cross-linking was achieved under low UV-irradiance thatresulted in densified films with excellent film retention (∼99%).Swelling studies showed that the BCP film is solvent-stable and exhibitslimited swelling despite domain-selective cross-linking. Interestingly,thenon-cross-linked domains remain available for solvent uptake, leadingto morphological reconstruction. These solvent-stable films were furtherused to fabricate layer-by-layer multilayer architectures while preservingthe laterally ordered nanoscale morphologies generated by BCP microphaseseparation. The combined findings establish a versatile platform thatintegrates block copolymer self-assembly with layer-by-layer nanofabrication,providing tunable multilayer nanostructures for applications in grayscalelithography, membranes, directed self-assembly, and multifunctionalcoatings.

Janushydrogels have garnered widespread interest due to theirinherent anisotropic dual-faced architecture and functionality, whichmake them especially valuable for diverse applications, includingsmart wound dressing, soft actuators, and wearable sensors. Herein,multifunctional Janus hydrogels with structural and functional dualityare facilely, rapidly, and one-step synthesized by frontal polymerization(FP) within 10 min. Through strong interfacial coupling, the two constituentlayers form a stable Janus architecture capable of withstanding largedeformations. Besides, the resultant hydrogels demonstrate tunablemechanical properties, exceptional extensibility (>500%), and greatself-healing and self-adhesive performance. Crucially, the anisotropicJanus design engenders pronounced gradients in the microporous morphologyand solvent uptake behavior. This asymmetry in the swelling capacitybetween the two layers drives solvent-induced bending deformation,allowing the bilayer hydrogels to operate as efficient underwatersoft actuators for grasping objects. Furthermore, the hydrogel isengineered into a flexible, stretchable, and antifreeze multimodalwearable sensor for real-time human-motion tracking and informationtransmission. Overall, this study presents a time-efficient, energy-conserving,and versatile approach to constructing multifunctional Janus hydrogels,thereby advancing the development of soft actuation systems and intelligentwearable electronics.

Thedevelopment of durable multifunctional cotton fabric with integratedwater repellency, UV protection, and self-healing capability remainschallenging due to insufficient environmental stability. Herein, arobust cotton fabric PU55Ti-6 was constructed through the synergisticincorporation of TiO₂ nanoparticles and a bio-based self-healingpolyurethane coating (PU-EuSi₅–HEDS₅).The resulting micro-nano structure and oleophilic–hydrophobiccomponents enable excellent water repellency, self-cleaning behavior,and efficient oil/water separation. TiO₂ nanoparticlestogether with eugenol-derived polyurethane provide strong UV protectionvia combined scattering and absorption effects. Dynamic disulfidebonds and phenol-carbamate within the polyurethane network enhancecoating durability and impart self-healing capability, enabling recoveryof water repellency of PU55Ti-6 after mechanical damage such as abrasion,peeling, and vigorous washing. The PU55Ti-6 also exhibits improvedmechanical strength, thermal stability and UV protective capacityrelative to pristine cotton even after thermal aging, outdoor exposure,and UV irradiation, demonstrating excellent environmental robustness.This work presents a simple and scalable strategy for designing durablemultifunctional cotton fabric for long-term applications.

Fabrication of underwater stable hydrogel coatings onsolid substratesvia a facile and scalable method remains challenging. This study presentsa simple bilayer hydrogel coating strategy for constructing underwaterstable and transparent hydrogel coatings on glass, wherein the amphiphilicpolyurea (PU) hydrogel and hydrophilic PU hydrogel serve as the bottomadhesive layer and top antifouling layer, respectively. By incorporatinga long aliphatic alkyl chain into the backbone of amphiphilic PU viaa special diisocyanate, the amphiphilic PU can assemble into a mechanicallyrobust (tensile strength >1 MPa) and antiswelling (water content≈45%) hydrogel with exceptional underwater adhesiveness. Meanwhile,the hydrophilic PU hydrogel is robust (tensile strength >1.5 MPa),antiswelling (water content ≈60%), and intrinsically superhydrophilic.Benefiting from the synergistic combination of these properties, thebilayer hydrogel coating achieves strong underwater adhesion to theglass substrate, retains high durability to various damaging tests,and maintains a nearly constant underwater–oil (CCl₄) contact angle of 148 °. Furthermore, the bilayer hydrogelcoating demonstrates outstanding underwater antioil-fouling and antiproteinadsorption (coverage of bovine serum albumin (BSA) <5%) performance,outperforming the single-layer amphiphilic PU hydrogel coating counterpart.This work provides a facile yet effective approach to constructingunderwater stable, transparent, and antifouling hydrogel coatingson glass, showing a promising practical application in underwaterantifouling of optical devices.

Intracellular radical polymerizationsoffer a bioorthogonalrouteto synthesize synthetic polymers within living cells, offering newavenues for cell engineering and the fermentative production of macromolecules.However, efficient delivery of polymerization components and the needfor exogenous catalysts remain challenges. Here, we report the developmentof a hemoglobin-based nanoreactor that self-assembles from amphiphilichemoglobin-polycaprolactone conjugates (Hb-PCL) into hollow vesiclescapable of initiating radical polymerizations inside living cells.When loaded with monomers and initiators, these nanoreactors can beinternalized by cells. Upon cellular uptake, the heme groups of thehemoglobin within the nanoreactor catalyze the polymerization withoutgenetic modification of the host or addition of external catalysts.In solution-phase reactions, the nanoreactors achieved 91% monomerconversion for N-isopropylacrylamide (NIPAm) after36 h. Upon cellular uptake by Raw264.7 macrophages, the Hb–PCLvesicles catalyzed intracellular polymerization of NIPAm, as confirmedby gel permeation chromatography, and supported copolymerization withfluorescein O-methacrylate to produce fluorescentP(NIPAm-co-FOM), enabling direct visualization by confocal microscopyand flow cytometry. This work introduces a new class of protein–polymerhybrid nanoreactors for intracellular chemistry, expanding the toolkitfor synthetic biology and cellular engineering.