ACS Applied Polymer Materials最新文献

The rapid development of modern precisionelectronic componentsplaced stringent demands on highly sensitive voltage overload protectionand thermal management, and the positive temperature coefficient (PTC)effect observed in conductive polymer composites (CPCs) played a crucialrole in this regard. However, once the polymer matrix had melted,most PTC composites exhibited a negative temperature coefficient (NTC)effect, while the excessive rigidity and brittleness of traditionalceramics limited their practical applications. This study presenteda PTC ink composite material. The method involved the synergisticuse of a thermosetting epoxy resin (EP) matrix and paraffin wax (PW),a material with a high expansion ratio, with γ-aminopropyltriethoxysilane(KH550)-grafted carbon black (KCB) serving as the conductive filler,printed on the film using screen printing. The results indicate thatthe formation of static covalent bonds and hydrogen bonds at the interfacebetween KCB and the epoxy resin effectively eliminates the influenceof NTC. This ink exhibits sensitive temperature responsiveness at30–50 °C, extends the PTC plateau, and achieves a PTCintensity of 3. Compared with traditional heating elements, this PTCink composite offers advantages such as rapid response, sensitivity,and the ability to meet the start-up temperature requirements of electronicdevices in cold conditions, as well as temperature self-limiting properties,safety, and convenience. These epoxy-based PTC composite materialsshow great promise in applications such as thermal protection forelectronic components and battery circuit protection.

Lithium metal batteries (LMBs) are promising next-generationenergystorage systems. However, their practical application remains limitedby safety concerns and poor compatibility with high-voltage cathodes,arising from interfacial instability, dendrite growth, and unevenion transport at the electrode–electrolyte interface. Solidpolymer electrolytes (SPEs) improve safety but still suffer from lowLi⁺ transference numbers and insufficient interfacial stability.Herein, a synergistic polymer, ionic liquid, and inorganic compositeelectrolyte (FALET) is developed to regulate ion transport and interfacialchemistry. The polymer/ionic liquid matrix facilitates Li⁺ transport, while EMIMTFSI also participates in interfacial electrochemicalprocesses during Li plating/stripping. TiO₂ nanofibersfurther regulate TFSI^– anions and promote lithiumsalt dissociation through Lewis acid interactions. The resulting cooperativeregulation of ion transport and interfacial chemistry homogenizesLi⁺ flux, promotes the formation of a dense inorganic richSEI, and suppresses dendrite growth. The FALET electrolyte exhibitsan ionic conductivity of 6.52 × 10^–4 S cm^–1, a Li⁺ transference number of 0.31, anda stability window of 5.01 V. It enables stable Li||Li cycling over2700 h and a Coulombic efficiency of 96% in Li||Cu cells. Full cellsfurther demonstrate stable cycling, high-voltage compatibility, andenhanced safety with improved flame retardancy and thermal stability.This work provides an effective strategy for developing safe and high-voltage-compatiblesolid polymer electrolytes.

Formation of macrovoidsin the membrane structure is a common occurrencein the process of nonsolvent-induced phase separation (NIPS), yetit is often undesired due to low structural homogeneity, poor performance,and introduction of weak mechanical points. Here, we introduce anether-based solvent, 2,5,7,10-tetraoxaundecane (TOU), for fabricationof macrovoid-free polysulfone (PSf) ultrafiltration (UF) membranes.We investigate how strong polymer–solvent affinity, high chainentanglement, and high viscosity influence the phase-inversion processand promote the formation of homogeneous membrane structures duringNIPS. Membranes prepared from PSf/TOU dope solutions exhibited stablesponge-like morphology, without macrovoids, in contrast to PSf membranesprepared from the more common solvent N-methyl-2-pyrrolidone(NMP), which typically display large fingerlike macrovoids. For PSf/TOUsystems, mixing ethanol and water in the coagulation bath led to fabricationof porous, permeable membranes while maintaining the macrovoid-freemorphology. Membrane performance was further optimized by changingthe polymer concentration and the addition of a pore-forming agentin the dope solution. The best-performing membranes showed pure waterpermeance between 149 and 204 L·m^–2·h^–1·bar^–1 and a bovine serum albuminrejection around 90%. This work establishes TOU as a previously unexploredyet effective solvent for NIPS fabrication of PSf UF membranes, enablingprecise control over membrane structure and effective suppressionof macrovoid formation and ultimately broadening the design spacefor PSf membranes.

Growing global demand for sustainable materials has driventhedevelopment of high-performance biobased epoxy resins. However, conventionalstrategies are plagued by reliance on fossil resources and subparperformance across key metrics (e.g., glass transition temperature,tensile modulus, and hygrothermal stability), making it difficultto simultaneously balance sustainability and high performance. Herein,an innovative biobased epoxy resin featuring a spirocyclic moleculararchitecture was synthesized from guaiacol (2-methoxyphenol), a lignin-derivedplatform monomer. Compared with diglycidyl ether of bisphenol A (DGEBA)thermosets, the cured networks exhibited a significantly higher glasstransition temperature (T_g) and enhancedtensile modulus. Furthermore, the networks exhibited exceptional hygrothermalstability, retaining 94.2% of their initial tensile strength and 93.7%of their initial tensile modulus after aging for 15 days under 60°C and 90% relative humidity. This paper introduces a macromoleculararchitecture design strategy centered on spirocyclic topology andestablishes a deoxygenation-free route to transform lignin-derivedmonomers into high-performance epoxy thermosets.

Achieving efficient hydrophobizationin polyurethanecoatings underlow-fluorine modification remains challenging because surface functionalitymust be introduced without compromising bulk cohesion and mechanicalintegrity. Here, a fluorinated AB-type polyurethane (PUAB) was designedby combining thermally triggered self-polymerization with postpolymerizationthiol–ene fluorination. The resulting PUAB matrix is stabilizedby hierarchical hydrogen bonding and π-related interactions,while the limited compatibility and low surface energy of the fluorinatedside chains promote their segregation toward the air-exposed surfaceduring film formation. This bulk-interaction-assisted fluorine enrichmentgenerated a fluorine-rich outer layer with submicron protrusions,enabling efficient surface hydrophobization at low fluorine content.Spectroscopic, thermal, microscopic, and computational analyses revealedthe relationship between polymer backbone interactions and surfaceorganization. The fluorinated PUAB coatings exhibited enhanced hydrophobicity,robust mechanical properties, good adhesion, and improved electrochemicalbarrier performance. This work provides a material design strategyfor constructing low-fluorine polyurethane coatings through the couplingof strong bulk interactions and surface fluorine enrichment.

Developing underwater adhesives that combine rapid curing,highadhesion strength, recyclability, and long-term durability remainsa significant challenge. Here, we report a recyclable underwater adhesive(AMN) synthesized via one-pot UV-initiated copolymerization of acrylicacid (AA), acrylamide (AM), and N-benzylacrylamide (NBAM) in dimethylsulfoxide (DMSO). The adhesive exploits synergistic hydrogen bonding,hydrophobic interactions, and π–π stacking to achievestrong and stable adhesion on various substrates. Under optimal conditions(monomer mass fraction 22%, NBAM dosage 65%, photoinitiator 5%, UVirradiation 3 h), the adhesive exhibits a shear adhesion strengthof 235 kPa on polycarbonate (PC) substrates, reaching 200 kPa within10 min. Notably, the adhesive can be reversibly disassembled in ethanol(100% dissolution within 7 h) while remaining stable in tap waterfor over 7 days. After five reuse cycles, 76% of the original adhesionstrength (178.5 kPa) is retained. The adhesive also maintains stableperformance on PC for 100 days. This work provides a green, solvent-responsive,and durable adhesive platform with promising applications in marineengineering, biomedical devices, and flexible electronics.

Hydrophilic modification is widelyused to improve the permeabilityand antifouling properties of PVDF membranes. However, introducingflexible hydrophilic segments significantly reduces the membrane’sresistance to deformation. To address this contradiction, a matureamphiphilic copolymer─fluoride-graft-poly(ethyleneglycol) methyl ether methacrylate (PVDF-g-PEGMA)─wasused as the hydrophilic component, while a multiarm rigid polystyrene(referred to as Star-PS) was introduced as a structural regulator.With the increase in Star-PS content, the average pore size and porosityfirst increased and then decreased. At the optimal Star-PS contentof 0.5 g, M₂ exhibited the largest average pore size of67.4 nm and the highest porosity of 75.1%; while when the contentincreased to 0.8 g, these values decreased to 59.8 nm and 71.3%, respectively.During the nonsolvent-induced phase separation process, Star-PS undergoeslocal aggregation and microphase separation, forming microspheresrich in polystyrene (PS), with an apparent equivalent diameter ofapproximately 250–350 nm. These retained rigid microregionscan regulate the evolution process of the polymer-rich and polymer-poorphases, promote the growth and connection of finger-like channels,and limit the deformation of the surrounding polymer matrix. However,excessive Star-PS will increase the viscosity of the casting solutionand delay phase separation, thereby partially inhibiting pore formation.Therefore, M₂ achieved a pure water flux of 556.4 L/(m²·h), a sodium alginate (SA) retention rate of 86.72%,and a flux recovery rate of 77.4%. Compared with M₀, itshardness, elastic modulus, and storage modulus increased from 1.6,25.34, and 24.84 MPa to 9.5, 125.82, and 35.9 MPa, respectively. Thus,the contribution of this study lies in the use of the in situ formedrigid microregions of Star-PS to compensate for the mechanical performancedegradation caused by hydrophilic modification, while maintaininggood permeability and antifouling properties.

Triboelectric nanogenerators (TENGs) using bio-basedor recycled-polymertribolayers offer a sustainable approach to energy harvesting. Thiswork reports TENGs comprising electrospun nanofibrous membrane (ENM)tribolayers produced from bio-based poly(ethylene furanoate) (PEF)and recycled poly(ethylene terephthalate) (rPET). All nanofibrousmembranes showed bead-free and smooth fibrous morphology. The PEFENM showed the smallest fiber diameter (230 ± 10 nm), whereasthe PEF/rPET blend ENM exhibited an intermediate average fiber diameterof 244 ± 13 nm and the most uniform fiber distribution. Stabilizingintermolecular interactions within the PEF/rPET blend contributedto its chemical, thermal, and mechanical stability. The single, mergedglass transition temperature (T_g) of thePEF/rPET membrane and the favorable miscibility parameter (Δδ≤ 5 MPa^1/2) supported substantial miscibility betweenthe amorphous phases of the two polymers. Compared with rPET, thebio-based PEF TENG exhibited an 11-fold increase in peak-to-peak voltage,reaching 11.4 V at 100 N and 20 Hz. The optimized PEF/rPET ENM-basedTENG produced the highest output of 33.8 V and 2.4 μA at 100N and 20 Hz, achieved a maximum power density of approximately 140mW/m² at 10 MΩ, and effectively charged commerciallyavailable capacitors. The optimized TENG harvested energy from anddetected various human motions, with a maximum peak-to-peak voltageof 400 V generated by finger tapping. Moreover, the voltage generatedby the TENG was sufficient to illuminate 15 commercial blue LEDs.Thus, the developed PEF and PEF/rPET ENM-based tribolayers providea promising pathway toward sustainable TENG fabrication and energyharvesting.

Biodegradableplastics capable of fully decomposing in naturalenvironments offer a promising solution to global plastic pollution.Polymer biodegradability is governed by multiple parameters, includingchemical composition, crystalline morphology, and sample geometry.Although the amorphous phase is hypothesized to undergo preferentialdegradation over its crystalline counterpart, direct evidence remainselusive. Herein, we investigated the marine biodegradability of polyamide6 (PA6) with varying crystallinities to elucidate the contributionof crystalline structure to its biodegradation behavior. This studyalso addresses the ongoing controversy in literature, where PA6 isinterchangeably reported as either biodegradable or nonbiodegradable.We demonstrated that PA6 biodegradability is strongly associated withits crystalline structure and sample morphology, including crystallinity,crystallite size, and surface accessibility. Cryo-milling enhancedthe biodegradation of PA6 particles by simultaneously altering theirparticle size, crystalline structure, and molecular weight, whereassubsequent reannealing markedly suppressed their biodegradation despitetheir small particle sizes. These results further support a strongcontribution of crystalline structure to PA6 biodegradation whilealso demonstrating that the effects of crystalline structure and samplegeometry are coupled. Furthermore, the preferential degradation ofless-ordered regions may leave crystalline remnants that are relativelyresistant to further biodegradation and could potentially contributeto the formation of persistent nanoscale particles. However, directcharacterization of such particles is required to verify this possibilityand evaluate their environmental implications.

The development of alkaline-stable and mechanically robustanion-exchangemembranes (AEMs) is crucial for advancing AEM-based fuel cells (AEMFCs),water electrolyzers (AEMWEs), CO₂ electrolyzers (AEMCO₂Es), direct ammonia fuel cells (DAFCs), and vanadium flowbatteries. In this work, efficient AEMs were fabricated by chemicallycross-linking quaternized poly(vinyl pyridinium) (QPVP) with quaternizedpoly(aryl piperidinium) (QPAP) to simultaneously enhance ionic conductivity,alkaline stability, mechanical integrity and electrochemical performance.The optimized cross-linked membrane exhibited enhanced hydroxide transportachieving a maximum conductivity of 128.4 mS cm^–1 at 90 °C compared to 68.8 mS cm^–1 for thepristine membrane. This improvement is attributed to the formationof a well-connected ionic network and improved phase-separated morphologyinduced by cross-linking. In addition, the cross-linked membranesdemonstrated superior alkaline durability, retaining stable conductivityafter prolonged exposure to harsh alkaline conditions. Electrochemicalperformance evaluation in H₂/O₂ AEMFC singlecell showed that the optimized membrane achieved a peak power densityof 0.88 W cm^–2 with a current density of 2.04 Acm^–2 at 80 °C significantly outperforming thepristine membrane. These results demonstrate that the cross-linkedQPVP-QPAP membrane is an effective strategy for developing high-performanceAEMs suitable for next-generation energy conversion and hydrogen productiontechnologies.