ACS Applied Polymer Materials最新文献

Polyhedral oligomeric silsesquioxane (POSS) coatings are known for their high hardness, wear resistance, and transparency. While modifying the organic substituents can tailor certain properties, the influence of the inorganic core’s size on mechanical performance remains unclear, and methods to control it are lacking. This study introduces a dynamic regulation strategy to precisely control POSS particle size and systematically investigates its impact on the properties of cured coatings. By employing a reaction-controlled condensation process─modulating temperature, rotation speed, and final concentration to remove byproducts─we produced POSS particles four times larger than those from uncontrolled reactions. The mechanical properties of the cured coatings were strongly proportional to the particle size. The optimized coating achieved a hardness of 0.462 GPa and a modulus of 17.008 GPa, significantly higher than the values for the uncontrolled sample (0.214 and 3.174 GPa, respectively). Furthermore, the coating exhibited excellent wear resistance, withstanding 10,000 cycles of steel wool abrasion under 12.5 kPa pressure without visible scratches. Critically, this method is also applicable to other raw materials, including hydrophobic and UV-curable variants. This work provides a versatile strategy for fabricating high-performance, hard, and flexible coatings with customizable properties.

A series of biobased poly(ester-thioether) thermosets was developed from sugar-derived methacrylate monomers and characterized for their structure–property relationships. Xylose, glucose, and sucrose were functionalized via a one-step esterification with methacrylic anhydride to yield tetra-, penta-, and octa-methacrylated monomers, respectively. Thiol-ene photopolymerization with five dithiol cross-linkers produced 15 distinct thermoset networks. Fourier transform infrared spectroscopy (FTIR) confirmed successful cross-linking through the disappearance of the thiol peak at ∼2560 cm^–1. Thermal analysis revealed that temperatures at 5% weight loss (T_5%) and midpoint degradation temperatures (T_mid) increased with cross-link density (ν_c), with sucrose-based networks exhibiting the highest thermal stability. Dynamic mechanical analysis (DMA) showed glass transition temperatures (T_g) between 73 and 96 °C and an inverse relationship between molecular weight between cross-links (M_c) and the storage modulus (E′), indicating that network rigidity is governed by both ν_c and monomer architecture. Alkaline degradation studies confirmed ester hydrolysis by mass loss over time, with degradation rates influenced by network structure. Soil degradation exhibited minimal yet detectable environmental degradation, suggesting a balance between durability and eco-responsiveness. These results highlight the potential of sugar-derived multifunctional monomers for designing degradable, high-performance thermosets for stereolithography (SLA) and digital-light processing (DLP) 3D-printing resins, transparent coatings, and recyclable adhesive systems.

The pursuit of advanced materials for resistive random-access memory (RRAM) has created significant interest in organic semiconductors due to their advantageous properties, including tunable electrical characteristics, flexibility, and low-fabrication cost. While resistive switching behavior has been well-studied in polymers like poly(3,4-ethylenedioxythiophene) (PEDOT), this study represents the first investigation of fused polydithienothiophene (PDTT) in this context. This work reports PDTT as a promising material for RRAM devices, with the device architecture as ITO/PDTT/Al. The structural, optical, morphological, and electrochemical characteristics of PDTT thin films were confirmed by FTIR, UV–visible absorption spectroscopy, FESEM, and cyclic voltammetry. The ITO/PDTT/Al devices exhibit forming-free, nonvolatile, and bipolar resistive switching, with a SET voltage of −1.0 V and a RESET voltage of +1.0 V. Device A, B, and C with varying PDTT layer thicknesses were fabricated to investigate the impact on resistive switching performance, device stability, and cycling endurance. Device A, with 41 nm PDTT layer demonstrates stable performance for 110 cycles with low switching voltages and good reproducibility, making it promising candidate for scalable, nonvolatile memory applications. Additionally, the compatibility of fused PDTT with ITO substrates, coupled with the simple device fabrication approach, enhances its potential for seamless integration into modern electronic devices.

Dielectric elastomers (DEs) are electroactive smart materials capable of significant reversible deformation under electric fields. Their muscle-like properties, including compliance, large strain, high energy density, and fast response, make them promising for artificial muscles and soft robotics. However, electromechanical instability (EMI) limits their practical application by preventing the simultaneous achievement of stability and large deformation. This study designed a dielectric elastomer with a bimodal network structure using cross-linkers of different chain lengths, solution processing, and UV curing. This created a network with long chains for extensibility and short chains to enhance modulus and suppress Maxwell stress instability, thus mitigating EMI. The resulting poly(2-ethylhexyl acrylate) (EHAP) elastomer film achieved 209% electrically induced strain, a two-order-of-magnitude increase in energy density, and a breakdown field strength of 88.5 V/μm. It maintained a low modulus, excellent cycling stability (100% strain retention after 2000 cycles at 2 Hz), and good response speed.

Polyimides are valued for their high thermal and chemical stability, making them an important membrane material for gas separation. Among them, Matrimid 5218 is particularly permeable to hydrogen over other gases. Membrane fabrication is primarily a solution process that utilizes large volumes of solvents, raising significant environmental and health concerns. Developing sustainable alternatives without compromising performance is a major challenge. Here, we introduce a bioinspired hydrogen-bonding strategy to dissolve Matrimid 5218 using natural solvents. We demonstrate that thymol and its mixtures with menthol and vanillyl alcohol form directional hydrogen bonds with the polymer’s carbonyl group, disrupting interchain interactions and enhancing solubility. The role of these green solvents, analogous to that of eutectic mixtures, was elucidated by thermal, rheological, and advanced spectroscopic techniques. Detailed 1D and 2D NMR analysis revealed how hydrogen-bonding interactions weakened polymer–polymer associations during dissolution, enabling the preparation of integral porous asymmetric membranes with a thin and highly selective separation layer. The resulting membranes achieve a gas separation performance comparable to those prepared with conventional toxic solvents. This work successfully demonstrates natural solid solvents for the fabrication of polyimide membranes for hydrogen separation and other applications.

Anion exchange membranes (AEMs) as the core component of anion exchange membrane fuel cells (AEMFCs) are responsible for hydroxide (OH^–) transport and preventing fuel crossover. However, traditional polymer matrix AEMs typically suffer from low conductivity and poor stability, which has constrained the development of AEMFCs. Here, we report a series of composite AEMs by incorporating guanidinium cationic covalent organic frameworks (TpTG_Cl) into N,N,N’,N’-tetramethyl-1,4-phenylenediamine (TMPD)-cross-linked imidazolium-functionalized poly(ether ether ketone) (qPEEK) via the solution casting method. The positive charge repulsion induces the self-exfoliation of TpTG_Cl to achieve covalent organic framework nanosheets (CONs), whose favorable dispersion enables a maximum doping content of 15 wt %. The high density of guanidinium cation groups in TpTG_Cl contributed to an ideal ion exchange capacity (IEC) of 2.92 mmol/g for composite AEMs. Moreover, the continuous cation domain and the additional one-dimensional (1D) nanochannels within TpTG_Cl enabled rapid transport of OH^–, resulting in a remarkable OH^– conductivity of 101.04 mS/cm (80 °C, 100% RH) for the qPEEK/TpTG_Cl-10 composite membrane. Meanwhile, the composite AEMs also exhibited enhanced mechanical strength (112.18 MPa), dimensional stability (SR< 18%, 30 °C), and alkaline stability (83.16% OH^– conductivity retention).

Mechanochromic sensors have become an attractive method for Structural Health Monitoring (SHM) due to their self-reporting and naked-eye visualization nature, making them ideal for stress-induced crack sensing and damage detection. A mechanochromic polymer film, Poly(MDI–PDA-PDMS-1), with a chromogenic polydiacetylene (PDA) component, was synthesized through a two-step process: copolymerization followed by UV irradiation to cross-link diacetylene templates to produce blue-purple Poly(MDI–PDA-PDMS-1). The Poly(MDI–PDA-PDMS-1) film displayed mechanochromic behavior with a visible color transition from blue-purple at 0% strain to red-orange at 200% strain. The strain-at-break was recorded at 204% with a corresponding stress value of 11.5 MPa. The Poly(MDI–PDA-PDMS-1) sensor was found to be stable under harsh conditions in highly acidic (pH 1.0) and basic (pH 14.0) solutions for 24 h. Importantly, the film was evaluated for crack monitoring in cement–concrete composites under flexural loading, where deformations in the PDA structure triggered a visible color change. Hence, Poly(MDI–PDA-PDMS-1) presents promising potential for self-reporting structural crack monitoring in the SHM process.

The pursuit of lightweight thermal protection systems has driven phenolic aerogels into the forefront of materials research owing to their excellent thermal insulation and ablation resistance properties. This paper introduces methods for preparing phenolic aerogel with thermosetting and thermoplastic phenolic resins as raw materials and discusses the development direction of ambient pressure drying technology, providing ideas for low-cost and large-scale preparation. Methods for modifying phenolic aerogel through molecular structure design are analyzed, suggesting that multielement synergistic hybridization can significantly improve the oxidation resistance and ablation resistance of phenolic aerogel. The preparation methods and properties of phenolic aerogel composites prepared using fibers and fillers as reinforcing phases are reviewed, expounding the influence of the reinforcing phase and its interface modification on the properties of the composites. Subsequently, the strategic design of a multifunctional phenolic aerogel was also deeply discussed. Based on the above progress, it is believed that future research in this field will focus on the molecular structure design of phenolic resin, special structural regulation of the reinforcing phase, and the development of multifunctional integration.

Alcoholic liver disease (ALD), a prevalent chronic liver disorder, has garnered global attention due to its significant health risks and limited treatment options. Recombinant granulocyte colony-stimulating factor (G-CSF), a drug with potent anti-inflammatory and antiapoptotic effects, shows limited utility in ALD therapy because of its short half-life. To address this limitation, we developed a hydrogel-encapsulated delivery system that prolongs G-CSF bioavailability, thereby enabling sustained suppression of cytokine release and apoptosis in ALD. The combination of recombinant G-CSF with carboxymethylcellulose sodium hydrogel (G-CSF&hydrogel) demonstrates excellent biocompatibility, controlled release, and favorable biosafety. G-CSF&hydrogel reduced alanine aminotransferase (ALT) levels from 190 IU/L to 70 IU/L and aspartate aminotransferase (AST) from 790 IU/L to 300 IU/L, compared with 110 IU/L and 460 IU/L for G-CSF alone, indicating enhanced therapeutic efficacy. RNA sequencing revealed that the enhanced inhibitory effects of G-CSF&hydrogel on ethanol (EtOH)-induced pathology in AML-12 hepatocytes were mediated via the HIF-1α signaling pathway. This study presents an effective strategy for developing advanced hydrogel-based drug delivery systems targeting inflammatory liver conditions.

The design and development of high-performance resins, along with the resourceful utilization of their waste, are of great significance to modern industry. This study employed magnolol, a renewable phenolic compound, combined with meta-/para-aminobenzonitrile through solvent-free synthesis to develop two benzoxazine monomers (M-mBN and M-pBN). The incorporation of cyano groups enabled the in situ formation of triazine rings during thermal curing. The research results demonstrated that the cured benzoxazine resins (poly(M-mBN) and poly(M-pBN)) exhibited outstanding comprehensive properties: ultrahigh glass transition temperature (T_g) exceeding 400 °C, initial thermal decomposition temperatures (T_di) of 434 and 416 °C, respectively, and char residues at 800 °C reaching 59% and 57%. In terms of flame retardancy, poly(M-mBN) showed a remarkably low heat release capacity of 98.5 J·g^–1·K^–1, meeting the criteria for noncombustible materials. These cyano-functionalized resins also exhibited low dielectric constants and inherent hydrophobicity, demonstrating a breakthrough in balancing renewable feedstock utilization with excellent performance. Moreover, poly(M-mBN) could be efficiently converted into a microporous carbon material (poly(M-mBN)-800) through carbonization. The resulting carbon exhibited a high specific surface area (1858 m²/g) and nitrogen-containing functionalities, enabling superior CO₂ adsorption capacity (up to 5.52 mmol·g^–1). The integrated strategy of molecular engineering, solvent-free processing, and functional group optimization addresses the longstanding performance gap between petroleum-based and biobased thermosetting resins and also offers a pathway for the green synthesis and environmentally friendly recycling of high-performance resins.