ACS Applied Polymer Materials最新文献

In practical applications, hydrogel sensors are requiredto withstandcontinuous tensile deformation and are highly susceptible to externalmechanical damage such as puncture. These issues often lead to irreversibledegradation of sensing performance, thereby limiting their furtherapplication. In this study, a self-healing hydrogel was fabricatedfor strain sensors by combining Schiff base reactions with metal coordinationinteractions. Sodium carboxymethyl cellulose (CMC-Na) was introducedas a functional reinforcement phase, and an optimal CMC-Na contentof 1.0 wt % was found to simultaneously enhance both the electricalconductivity and mechanical properties. The resulting PAA/PEI/CMC-Na–Cur–Al³⁺ hydrogel exhibits an ionic conductivity of 1.07 S/m anda tensile strength of 77.12 kPa, yielding an approximately 5-foldenhancement compared to the hydrogel without CMC-Na. The hydrogelsensor also demonstrates a gauge factor of 2.15 and stable sensingperformance over 2500 s of cyclic stretching. It is capable of detectinghuman joint movements and can be applied as a stylus. These superiorproperties demonstrate that the PAA/PEI/CMC-Na–Cur–Al³⁺ hydrogel is an ideal candidate material for flexible strainsensors.

Despite extensive studies of hyper-crosslinked polymers(HCPs)for carbon dioxide adsorption and separation, the fundamental roleof aromatic precursor topology in governing localized gas confinementand molecular recognition has remained poorly understood. Herein,we demonstrate that the geometric topology of aromatic precursors,spanning isolated aromatic rings, rigid fused polycyclic frameworks,and rotationally flexible biaryl linkages, directly controls frameworkpacking and micropore generation. Systematic variation of precursortopology reveals distinct relationships between porosity, adsorptionaffinity, and molecular selectivity. Comprehensive structural, thermodynamic,and adsorption analyses, including Henry’s law constants (K_H), isotherm model fitting, and isosteric heats of adsorption (Q_st), reveal that topology-controlled confinement may promote cooperativemulti-body interactions. Benzene-derived HCP, with the most accessibleultra micropores, delivers the highest CO₂ uptake (74.0cm³ g^–1 at 273 K and 1 bar) and K_H (109 mmol g^–1 bar^–1). Anthracene-derivedHCP, with its rigid fused-ring geometry, instead achieves the highestCO₂/N₂ selectivity (557 at 273 K and 0.01 bar)and Q_st (32.0 kJ mol^–1), suggesting a possible contributionfrom cooperative multi-body interactions between CO₂ andthe confined aromatic framework. This enhanced energetic interactionis accompanied by suppressed N₂ adsorption, rather thanby increased CO₂ capacity. Overall, these results demonstratethat CO₂ uptake and CO₂/N₂ moleculardiscrimination arise from distinct aspects of framework architecture,highlighting aromatic precursor topology as a key structural parameterfor tuning gas adsorption and separation in HCPs.

5-Vinyl-2-norbornene (VNB) is a cyclic olefin monomercontaininga norbornenyl double bond and a vinyl double bond. Selective insertionof the norbornenyl double bond during the Ziegler–Natta homopolymerizationand copolymerization of VNB produces polyolefins bearing pendant vinylgroups available for subsequent chemical transformation. This reviewsurveys previous studies on the synthesis and postpolymerization modificationof VNB-derived polyolefins. Particular attention is given to the relationshipsbetween synthetic methodologies and polymer molecular structures,including molar mass, molar mass distribution, copolymer composition,preservation of pendant vinyl groups, and postpolymerization modificationefficiency. On the basis of these findings, key synthetic requirementsfor developing model polymers that are capable of revealing intrinsicstructure–property relationships are discussed. These includeliving polymerization with complete chemoselectivity, programmablecontrol of monomer sequence distribution, and expanded functionalizationmethodologies. These capabilities would provide independent controlof molar mass, topology, composition, and chemical functionality.This review is intended to highlight the potential of VNB-derivedpolyolefins as platforms for the development of model polymers thatcontribute to the understanding of polymer structure–propertyrelationships and the rational design of high-performance appliedpolymer materials.

Conductiveelastomers have attracted considerable interestforelectronic skin and wearable health-monitoring devices. Although softand self-healing polyurethane elastomers have been extensively developed,the simultaneous integration of mechanical robustness, stable ionicconductivity, recovery of both mechanical and electrical functions,interfacial adhesion, cyclic durability, and reliable sensing overa wide temperature range remains challenging. In particular, increasingpolymer-chain mobility may promote ion transport and interfacial healingbut can compromise mechanical strength and dimensional stability,whereas reinforcement of the polymer network may restrict moleculardiffusion and ionic migration. To address these trade-offs, we introducea ChCl/AA deep eutectic solvent (DES) into a dynamic polyurethane(PU) network through solvent exchange. The optimized PU-DES-4 exhibitsa tensile strength of 2.71 MPa and an ionic conductivity of 3.81 ×10^–2 S m^–1 at 25 °C. Itsself-healing behavior is strongly temperature dependent: mechanicalrecovery exceeds 90% after healing at 60 °C for 3 h but reachesapproximately 50% and 65% after 12 h at 25 and 37 °C, respectively.The material also shows spontaneous room-temperature adhesion, witha metal lap-shear strength of approximately 138 kPa without thermalactivation; this value increases to 2.67 MPa after thermal conditioningat 60 °C for 30 min. In addition, PU-DES-4 maintains stable sensingperformance from −20 to 50 °C and supports wearable motionand physiological signal monitoring. These results demonstrate a DES-mediatedstrategy for balancing mechanical, ionic, interfacial, and sensingfunctions while also identifying mild-temperature healing and quantitativelong-term retention as areas requiring further optimization.

Conjugatedporous organic polymers (CPPs) have emerged as promisingphotocatalysts because of their high surface area and efficient abilityto collect and transport light energy through their delocalized backbone.Nevertheless, their synthesis methods require expensive monomers,stringent experimental conditions, including inert atmosphere, elevatedpolymerization temperature, and the use of metals as catalysts. Toovercome these limitations, a triphenylamine-based conjugated porouspolymer (TPA-TTA) has been prepared through a one-potSchiff base reaction in ambient conditions in the absence of a metalcatalyst. In this synthesis, 5’,5,5″-(benzene-1,3,5-triyl)tris(thiophene-2-carbaldehyde)(TTA), a stiff aromatic aldehyde, was condensed with tris(4-aminophenyl)amine (TPA). Diffuse reflectance spectroscopy (DRS) analysis revealedan optical band gap of 2.01 eV, confirming its semiconducting behavior.Electron paramagnetic resonance (EPR) analysis exhibited a pronouncedradical signal at g = 2.00, suggesting the efficientformation of free radicals upon visible-light exposure which can promotethe photocatalytic degradation of organic contaminants. The Brunauer–Emmett–Teller(BET) analysis indicates that TPA-TTA has a porous frameworkwith a surface area of 109.3 m² g^–1,while thermogravimetric analysis (TGA) demonstrates its good thermalstability up to 333 °C. Photocatalytic studies further show that TPA-TTA achieves effective degradation of 88.38, 91, 90.4,94, 79.8, 82 and 95% for TC, HQ, PCM, MO, AMX, NR, and RHB upon visible-lightexposure, respectively. Owing to the protonation of imine moietiesin the polymeric framework upon exposure to HCl vapors, TPA-TTA exhibits a pronounced “turn-off” fluorescence responsealong with a rapid (2s) visible color change to the naked eye. Thecolor change of TPA-TTA triggered by HCl vapors is fullyreversible upon exposure to NH₃ vapors, demonstrating itsstrong reversibility and reusability. The protonation–deprotonationmechanism was also supported by Fourier transform infrared (FTIR)spectroscopy and X-ray photoelectron spectroscopy (XPS) studies. Theseinsights underscore the feasibility of large-scale production of metal-freeconjugated porous polymers as dual-functional materials, serving asphotocatalysts and reversible naked-eye solid-state HCl sensors.

A light-driven heterostructure wasdeveloped by depositinga Copper-dopedBismuth Ferrite (Cu–BFO) thin film onto a flexible poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) substrate.Unlike conventional photoactuators governed primarily by photothermalexpansion, this bimorph demonstrates a fully reversible bending consistentwith a photostriction-dominated response. Kinetic decoupling and isothermalanalysis at a fixed thermal threshold of 35 °C explicitly reveala severe performance divergence: under 405 nm violet illumination,the actuator triggers an instantaneous mechanical deflection reachingan average maximum bending angle of 79.9° ± 0.7°, whereas532 nm green and 635 nm red light yield near-zero, baseline thermalresponses (2.8° ± 0.3° and 5.7° ± 0.9°,respectively). This strict wavelength selectivity, with significantresponse occurring only above the Cu–BFO bandgap, stronglysupports the actuation predominantly photostrictive mechanism. Theresulting internal electric field induces lattice strain through theconverse piezoelectric effect, providing a highly efficient light-to-mechanicalenergy conversion pathway. Finally, a light-controlled microgrippercapable of lifting objects weighing 1.9 mg with a payload-to-weightratio of 1.58, demonstrates the practical potential of this heterostructurefor remotely powered soft robotic and haptic applications.

To address the issues of high cost, non-biodegradability,and complexpreparation processes of conventional fluorescent anti-counterfeitingmaterials, this study developed a series of biodegradable fluorescentfilms with aggregation-induced emission (AIE) characteristics usingpine holocellulose and pure cellulose as substrates. Through acetoacetylationfollowed by the Hantzsch multicomponent reaction, formaldehyde, vanillin,and cinnamaldehyde were respectively grafted onto fiber surfaces toconstruct 1,4-dihydropyridine (DHP) fluorescent structures. Structuralcharacterizations confirmed the successful construction of DHP moieties,and the nitrogen content was consistently higher for holocellulose-basedmaterials than for cellulose-based counterparts, indicating that hemicelluloseenhances fiber accessibility and grafting efficiency. UV–visabsorption and fluorescence measurements revealed that the cinnamaldehyde-modifiedfilm exhibited the strongest UV absorption yet the weakest fluorescence,while the formaldehyde-modified film showed moderate UV absorptionbut the strongest fluorescence; holocellulose-based films outperformedcellulose-based films in both UV absorption and fluorescence intensity.The prepared waterborne inks exhibited shear-thinning rheology, thixotropy,and favorable yield stress, satisfying screen-printing requirements.Printed patterns were invisible under daylight but emitted brightblue fluorescence under 365 nm UV light, with excellent solvent andthermal stability. This work provides a pathway for developing high-performance,biodegradable bio-based anti-counterfeiting inks.

The separator material is a critical component that governsthecycling performance of aqueous zinc-ion batteries (AZIBs); however,how its ion transport properties dictate specific electrochemicalbehaviors remains poorly understood. Here, we investigated the relationshipbetween ion transport properties and AZIB performance using Zn²⁺-substituted Nafion® (Zn-Nafion®) membranes asmodel ion-exchange membranes. By separately characterizing electric-field-drivenion migration and concentration-gradient-driven diffusion, we identifiedthat rate capability is primarily influenced by ion conductivity,while long-term stability is governed by ion permeability, as furtherconfirmed by numerical simulation. Guided by this principle, we chemicallyactivated a Zn-Nafion® membrane optimized for both parameters,which demonstrated exceptional cycling stability even under high-rateoperation (5.0 A/g). These findings clarify the distinct roles ofion transport in AZIBs and offer a rational strategy for designingadvanced membrane materials.

Natural silk fibers hold considerable promise for implantapplications.However, how to enhance bioactivity while preserving mechanical performanceremains a challenge. Herein, a strategy combining soaking with secondarywashing was employed to achieve loading of metformin while largelyretaining the mechanical properties of silk fibers. Multiscale structuralcharacterization revealed the noncovalent interactions between metforminand silk in the amorphous regions and a slight decrease in fiber orientationand β-sheet nanocrystals. Owing to the stable structure, themetformin-loaded silk fibers retained excellent mechanical properties,exhibiting a tensile strength of 407.8 MPa and a toughness of 36.7MJ·m^–3. Notably, the Weibull shape parameterfor tensile strength reached 28.53, indicating mechanical reliability.Furthermore, the metformin-loaded silk fibers demonstrated favorablecytocompatibility and enhanced osteogenic activity. This study providesa facile and mild strategy for the bioactive modification of naturalsilk fibers while preserving their structural and mechanical properties.