ACS Applied Polymer Materials最新文献

Polymeric ionic liquids (polyILs) with high-salt concentrations are promising polymer electrolytes for lithium and sodium metal batteries. While prior studies have focused on single-anion systems, this work investigates mixed-anion high-salt polyILs at a 1:2 polyIL-to-salt ratio by using combined computational and experimental approaches. Clear phase separations are observed both computationally and experimentally, related to distinct anion structures, large disparities in Na⁺-anion binding strength, and differences in ion-packing stability, which collectively affect anion coordination tendency and electrolyte microstructure. In the molten salt subphase, molecular dynamics simulations reveal highly correlated Na⁺-anion diffusion, with markedly higher diffusivities for Na⁺ and BF₄^– within tens of nanoseconds. However, diffusivity decreases substantially after ∼200 ns of equilibration due to NaBF₄ crystallization, consistent with experimental observations. Although crystallization phenomena are experimentally observed across all mixed-anion systems, they remain difficult to fully capture within 300 ns of MD simulation, highlighting the need for advanced modeling techniques. Overall, this study elucidates the behavior of polyILs with mixed anions, revealing the fundamental challenges of the mixed-anion designs and the importance of iterative modeling–experiment–modeling approaches for rational computational electrolyte development.

Macro-monomer (macromer) containing eight epoxy groups (SU-8), which is known as a photoresist for photolithography, was synthesized and subsequently converted into a series of epoxy-methacrylate macromers via epoxy ring opening with 2-hydroxyethyl methacrylate (HEMA). The resulting macromers were employed in 3D printing resin formulations. The epoxy to methacrylate conversion was confirmed using proton nuclear magnetic resonance (¹HNMR) spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy, and titration. The glass transition temperature (T_g) increased from −25.7 to 12.5 °C with increasing methacrylate content, as determined by differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) demonstrated a decrease in thermal stability as the methacrylate functionality increased, with the fully methacrylated macromer (FA) losing up to 62% of its weight between 150 and 330 °C. For the study of the photocuring kinetics, ultraviolet (UV)-FTIR, along with the mechanical properties, demonstrated improved curing rate, higher volumetric shrinkage, and enhanced mechanical performance with increasing methacrylation, indicating optimized performance for vat photopolymerization-based 3D printing.

Conductive hydrogels have gained increasing attention due to their applications in flexible electronic devices and biosensors. Here, a gelatin-poly(vinyl alcohol) and LiCl composite conductive hydrogel (GP-Glu@LiCl) with good permeability and controllable adhesiveness was prepared by using gelatin and poly(vinyl alcohol) (PVA) as the gel matrix, 1-ethyl-(3-(dimethylamino)propyl) carbamoyldiimide (EDC) and N-hydroxybutanediimide (NHS) as cross-linking agents, and microbial fermentation as a pore making method. It is notable that the GP-Glu@LiCl hydrogel has adjustable pore size (139.99–315.52 μm), high permeability, high extensibility (with a tensile strain reaching 347.48%), good conductivity (1.78 S/m), and excellent adhesion strength. Moreover, the flexible sensor made of GP-Glu@LiCl hydrogel has high sensitivity and excellent strain sensing performance, which can be applied to the detection of human electrophysiological signals and the monitoring of changes in human movements. Through electromyogram (EMG) sensing, it enables the c ontrol of robotic arms and simple games. It has broad application prospects in wearable sensors and flexible electronic devices.

Advanced materials with tunable wettability and nanoscale surface patterning are vital for both fundamental studies and application-driven technologies. This work investigates how pH, ionic strength, and layer-by-layer (LbL) deposition strategies influence the structural evolution and surface features of branched polyethylenimine (BPEI)/poly(styrenesulfonate) (PSS) multilayers. The LbL strategy was employed using both conventional single-pH deposition and an alternating pH-stack assembly (ApHSA) approach to investigate how interdiffusion and electrostatic modulation drive structural and surface changes. At 0.4 M NaCl, films assembled at pH 5 exhibited granular nodules that coalesced into a vermicular network accompanied by linear growth and hydrophilic surfaces. In contrast, films deposited at pH 9 showed exponential growth, evolving from fine clusters to smooth hydrophobic surfaces. Water contact angles varied widely from 47° (pH 5, 1 M NaCl, 5 bilayers) to 103° (pH 9, 0.4 M NaCl, 10 bilayers), indicating a strong sensitivity to deposition conditions. The ApHSA protocol, applied at 0.4 M NaCl, produced sigmoidal growth curves and surface morphologies that transitioned from vermicular patterns to discrete aggregates over successive stack units. This progression reflects enhanced lateral and vertical interdiffusion enabled by optimized ionic screening. Concurrently, wettability shifted smoothly from hydrophobic to hydrophilic with increasing stack units. Preliminary transport measurements revealed that ApHSA multilayers exhibit improved methanol blocking while maintaining moderate proton conductivity, reflecting a more selective ionic architecture. Although the overall performance is not yet superior to that of benchmark Nafion membranes, these results demonstrate that pH-programmed charge modulation can balance transport selectivity and morphological control. These findings demonstrate that simple modulation of the deposition pH enables programmable control over multilayer architecture and surface properties using standard polyelectrolytes. The ApHSA strategy offers a scalable and versatile platform for engineering multifunctional polymer coatings with tailored interfacial characteristics.

High-strength electrochemical corrosion-resistant materials hold significant application value in marine engineering and construction sectors. In this study, cellulose nanocrystals (CNCs) extracted from microcrystalline cellulose (MCC) via sulfuric acid hydrolysis were incorporated into polyurethane (PU) through in situ polymerization to systematically investigate the effects of CNC addition timing (soft segment, hard segment, chain extender, and prepolymer stages) on material properties. Low-field nuclear magnetic resonance (LF-NMR) relaxation analysis revealed that introducing CNC during the prepolymer stage most dramatically enhanced molecular chain rigidity, as evidenced by the most pronounced relaxation decay. Fourier transform infrared spectroscopy (FTIR) confirmed that CNC incorporation significantly increased the hydrogen bonding index (HBI), with later addition stages yielding greater HBI enhancement. Dynamic mechanical analysis (DMA) further demonstrated that prepolymer-stage CNC addition substantially improved dynamic cross-linking density, thereby endowing the composites with superior mechanical performance. Electrochemical impedance spectroscopy (EIS) measurements showed a remarkable 2–4 orders of magnitude increase in impedance modulus for all PU/CNC composites, validating CNC’s corrosion protection efficacy.

Microgels have excellent biocompatibility and tunable physicochemical properties but poor mechanical properties that severely limit their application. In this study, a strategy is developed to synergistically enhance the mechanical properties of microgels by absorbing secondary cross-linked hydrogel precursor solution and adding an interstitial matrix. The results show that PEGDA-NAGA microgels enhanced by an interstitial matrix exhibit excellent mechanical properties, with a tensile breaking stress up to 0.7 MPa and tensile breaking strain up to 120%, improving the performance of conventional microgels. Furthermore, the microgel ink viscosity increases 10-fold and significantly improves printing fidelity. The mechanical properties of the printing ink can be flexibly regulated by adjusting the type of hydrogel precursor solution and interstitial matrix addition. This flexible and versatile method improves the mechanical properties 5-fold. The modular cross-linking method provides an approach to microgel ink development and offers broad application prospects in tissue engineering and regenerative medicine.

Traditional carbon-based additives often exhibit irregular morphology and poor dispersion, which hinder the overall performance of poly(lactic acid) (PLA) composite films. To overcome these limitations, a hybrid nanonetwork structure (CQDs@TiO₂) was constructed via the in situ integration of carbon quantum dots (CQDs) derived from wheat straw, an agricultural waste, with titanium dioxide (TiO₂), and subsequently embedded into the PLA matrix. Additionally, three representative interface compatibilizers─4,4′-methylenebis(phenyl isocyanate) (MDI), tannic acid (TA), and the ionic liquid [BMIM][BF₄] (IL)─were employed to functionalize the nanofillers and tailor interfacial interactions. The effects of these modifiers on the physicochemical properties of both CQDs and CQDs@TiO₂ were systematically evaluated, and their influence on the ultraviolet-shielding performance, crystallization behavior, thermal stability, biodegradability, and mechanical performance of PLA composites was comprehensively investigated. Notably, the tensile strength and toughness of PLA/CT-MDI and PLA/CT-IL composites reached 68.28 MPa and 4.53 MJ/m³, representing enhancements of 65.9% and 335.6% over pure PLA, respectively. These improvements were attributed to the synergistic effect between the rigid CQDs@TiO₂ nanonetwork and flexible interfacial regulators, which promoted nanofiller dispersion, interfacial adhesion, and structural cohesion. This work demonstrates a versatile interfacial engineering strategy for developing high-performance, biodegradable PLA materials, with potential applications in packaging, biomedicine, and environmental sustainability.

Effective personal thermal management, particularly passive cooling without perspiration or energy input, is crucial for enhancing comfort and reducing energy consumption. Heat conduction and radiation represent two key passive cooling mechanisms for textiles, yet concurrently optimizing both remains challenging. Conventional approaches struggle to integrate high-thermal-conductivity fillers like boron nitride nanosheets (BNNS) and high-emissivity materials like silica (SiO₂) due to nanoparticle aggregation, uneven dispersion, and functional interference within a single matrix, which compromise performance and spinnability. This work reports a coaxial wet-spinning method to fabricate hydroxyl-functionalized boron nitride nanosheet/silica (OH-BNNS/SiO₂) double-doped thermoplastic polyurethane (TPU) fibers. This technique achieves hierarchical functional separation: OH-BNNS confines within the core to enhance thermal conductivity, while SiO₂ nanoparticles incorporated into the sheath promote radiative cooling via high mid-infrared emissivity (7–14 μm). Optimized fibers (30 wt % OH-BNNS core) achieve a thermal conductivity of 1.715 W·m^–1·K^–1 and a 572.55% improvement over pure TPU. The SiO₂ sheath provides over 90% visible-light reflectance and reduced mid-infrared reflectance, enabling efficient radiative dissipation. OH-BNNS enhances tensile strength of TPU fiber to 4.68 MPa via hydrogen bonding. OH-BNNS/SiO₂ double-doped woven fabric exhibits superior cooling performance (54% lower heating rate than pure TPU under sunlight) and high air permeability (285.9 mm/s under a pressure drop of 100 Pa). This work provides a scalable manufacturing strategy for multifunctional cooling textiles that integrate passive radiative and conductive cooling mechanisms, showing significant potential for energy-efficient personal thermal management.

Surface-grafted polymer brushes offer a powerful way to engineer nanobio interfaces, yet threading these through the maze-like morphology of nanoporous gold (npAu) electrodes remains difficult: the extreme curvatures, narrow necks, and long diffusion paths hinder monomer transport, limiting chain growth. In this work, we systematically examine how pore topology, grafting strategies, and reaction parameters govern brush formation inside npAu and establish polymer-coated electrochemical biosensors. Electroanalytical diagnostics, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), reveal that graft-to strategies generate sparse coverage, while graft-from strategies using surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) of poly(2-hydroxyethyl methacrylate) (PHEMA) or poly(sulfobetaine methacrylate) (PSBMA) produce dense brushes, fully infiltrating the three-dimensional nanoporous network. Increasing initiator coverage or extending polymerization time progressively attenuates charge transfer. However, intermediate conditions yield the optimal balance, creating robust brush networks while preserving electrochemical activity and biosensing performance. Notably, complete passivation occurs far more rapidly on planar gold (pAu) than on thermally annealed npAu, highlighting the unique role of hierarchical porosity in regulating polymer growth. Finally, utilizing a PHEMA-coated npAu electrode as the sensing substrate of an electrochemical aptamer-based (EAB) biosensor retains pharmacologically relevant sensitivity, indistinguishable from that of unmodified electrodes, validating this approach for next-generation, fouling-resistant electrochemical biosensors.

Shape memory polyetherimides (SMPEIs), known for their exceptional thermal stability, mechanical strength, and chemical resistance, are promising candidates for high-performance applications in smart devices and aerospace. However, achieving simultaneously ultrahigh and stable shape fixity (Rf) and recovery ratios (Rr) remains a significant challenge. In this study, inspired by the structural features of elastin in human skin, we designed a novel elastic, network-like cross-linking junction (NCJ). Incorporation of NCJs into SMPEIs yielded outstanding shape memory performance (Rf ∼ 97%, Rr ∼ 96%), surpassing conventional linear SMPEIs (commercial Ultem 1000: Rf ∼ 87%, Rr ∼ 66%) even after six cycles. This improvement is attributed to the NCJ’s ability to anchor the topological network and enhance resilience at elevated temperatures. Benefiting from the high-temperature activation mechanism of NCJs, SMPEIs exhibit remarkable multifunctionality, enabling their application in areas such as adhesives and 3D printing. This study not only presents a practical and efficient approach to enhancing the shape memory performance of high-performance engineering plastics but also greatly expands their applicability in demanding environments that require exceptional thermal resistance and mechanical robustness.