ACS Applied Polymer Materials最新文献

Self-healing polymers can recover from physical and chemical damage autonomously, which improves the durability and performance of systems that rely on these polymers. To design self-healing polymers that work well in practical applications, it is important to understand the impact that the presence of different ions has on self-healing mechanisms. In this paper, we investigate the role of monovalent (Na⁺) and divalent (Ca²⁺) ions in the self-healing efficiency of a model polymer, namely, poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), whose network is dominated by hydrogen bonding. By pre-embedding ions into the bulk gel, our method systematically eliminates the confounding ion concentration gradients and osmotic pressure differences that complicated previous studies. Through tensile testing, we find that at high concentrations, divalent ions improve the strength and modulus recovery of polymer samples and slightly reduce the strain recovery relative to samples without any ions in them. Monovalent ions did not result in a statistically significant change in strength recovery but increased strain recovery at high concentrations. Using additional rheological measurements, we find that both monovalent and divalent ions decrease the relaxation time of the PAMPS chains, with monovalent ions doing so to a much larger extent. This suggests that changes in chain mobility might be the key factor that controls any improvements in strain and strength recovery. Overall, our results deconvolute the competing roles of ionic cross-linking and chain mobility and highlight the importance of controlling for osmotic artifacts in ion-containing hydrogels.

Stretchable ionic conductors have emerged as promising materials for next-generation flexible energy and sensing devices. However, simultaneously achieving mechanical robustness, autonomous self-healing, and high ionic conductivity within one material system remains challenging. Here, we developed a tough, self-healing ionic conductive elastomer (TSHICE) based on a bioinspired, functionally partitioned design. Mimicking the hierarchical architecture of human skin, TSHICE integrates a polyether soft phase that forms continuous Li⁺ transport pathways with a dynamic hard phase composed of cooperative strong and weak hydrogen bonds. The dynamic hard domains act as reversible cross-linking sites, imparting mechanical integrity and efficient self-repair while maintaining reliable ionic conduction. As a result, TSHICE achieves a high fracture energy (89.8 kJ m^–2), an ionic conductivity of 3.27 × 10^–3 S m^–1, high tensile strength (11.8 MPa), remarkable toughness (136.5 MJ m^–3), rapid room-temperature self-healing, and good optical transparency. Capacitive sensors fabricated from TSHICE exhibit fast response (≈23 ms) and multisignal recognition capabilities, demonstrating strong potential for advanced sensing applications. This bioinspired design strategy offers insight into the development of ionic elastomers with integrated mechanical robustness, self-healing capability, and efficient ionic transport enabled by continuous ion-conducting pathways.

Membrane separation technology has been widely employed in water purification and efficient pollutant removal. In this research, a core–satellite structured bimetallic metal–organic framework (MOF) (MIL-53(Al, Fe)–OH) was grown onto the surface of an electrospun polyamide 66 (PA66) nanofiber membrane via a hydrothermal method. Benefiting from the intrinsic properties of MIL-53(Al, Fe)–OH and the high specific surface area of PA66 membranes, the PA66@MIL-53(Al, Fe)–OH membranes exhibit high wettability and excellent adsorption-photocatalytic and oil/water separation properties. And the prepared membrane demonstrates excellent hydrophilicity and underwater superoleophobicity, with a flux recovery rate of 86.60% for the soybean oil emulsion. Moreover, the incorporation of bimetallic MOFs enhanced photocatalytic activity through the interfacial carrier transfer mechanism, leading to a methylene blue removal rate of nearly 100% within 1.5 h under an alkaline environment. Additionally, the composite membrane maintains a stable wettability in complex chemical environments. These results provide an efficient and sustainable strategy for treating oily wastewater and degrading organic pollutants.

Rectorite nanosheets (RNs) with large aspect ratios, high surface reactivity, and superior mechanical properties have promising applications in many fields. However, the efficient fabrication and assembly of RNs into high-performance nanocomposites for practical applications remains a challenge. In this work, a facile cellulose nanofiber (CNF)-assisted method was developed for exfoliating high-quality RNs and preparing CNF/RNs nanocomposite films. This method achieved a high yield of 69.1% for RNs with a large aspect ratio of ∼144. The CNF/RNs nanocomposite films formed via vacuum filtration showed a highly ordered “brick-and-mortar” microstructure with outstanding mechanical properties. Especially, the optimized CNF/RNs nanocomposite film with 20 wt % RNs (CR-20) had a tensile strength of ∼219 MPa and a Young’s modulus of ∼1.7 GPa, along with excellent heat-resistant performance. Moreover, the CR-20 film displayed a high limiting oxygen index (LOI) of 32.1% and self-extinguishing behavior in vertical combustion experiments. Our proposed strategy provides an avenue for fabricating high-performance rectorite-based nanocomposites, which have great potential as substrates for solid-state electrolytes, wearable sensors, and aerospace applications.

Functional hydrogels with on-demand detachability and a visually intelligible adhesion switch hold significant promise for wound healing, biomedical diagnostics, and wearable sensors. Conventional hydrogels offer desirable properties such as flexibility, biocompatibility, and tissue-like mechanical properties. However, developing multifunctional hydrogels that integrate skin-conformable adhesion, controllable detachment, visual adhesion switching via tunable transparency, body-temperature responsiveness, and excellent biocompatibility remains challenging. Inspired by octopus suckers and leveraging hydrogen-bond-driven adhesion between monomers, we fabricated a hydrogel with suction-cup-like structures using vat photopolymerization-based 3D printing. The resulting hydrogel exhibits strong, reversible adhesion, with adhesive strength varying with temperature. Simultaneously, its tunable optical properties enable visual monitoring of adhesion through transparency changes. Specifically, the hydrogel adheres firmly to human skin at body temperature to aid wound healing. Upon recovery, it detaches cleanly by heating to 50 °C, leaving no residue and minimizing skin damage. Moreover, the hydrogel demonstrates excellent biocompatibility, with cell survival exceeding 98%, and antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus, with inhibition zones of 14 mm and 24 mm. In summary, this bioinspired 3D-printed hydrogel unites skin-adaptive adhesion, visually switchable adhesion, high biocompatibility, and on-demand detachability, offering great potential for advanced wound care, wearable electronics, and intelligent medical patches.

With concerns about environmental pollution and the depletion of fossil resources, it is essential to adopt strategies to provide multifunctional materials by utilizing abundant and sustainable feedstocks. However, developing biobased polymeric materials with properties comparable to petroleum-based counterparts remains a great challenge. In this work, a series of polyamides were synthesized from plant oil-based E-octadec-9-enedioic acid monomer (C18) and diethylenetriamine via a facile one-pot approach, incorporating both dynamic hydrogen bonds and permanent covalent cross-links. By adjustment of the molar ratio of C18, the resulting polyamide (PA1.2) presents remarkable mechanical properties, including a high tensile strength of 30.3 MPa and an elongation at break of 611.8%. Moreover, the combination of reversible H-bonds and flexible long aliphatic chains endows elasticity and reprocessability to the thermosetting polyamides. The significant H-bond interactions, along with multipolar functional groups, also contribute to the polyamides’ strong adhesion to a variety of substrates, such as steel, wood, and other materials. These structural characteristics synergistically enhance the adhesion performance, with the polyamide adhesive achieving a robust adhesion strength of 14.28 MPa and excellent temperature adaptability. Notably, all of the obtained polymers exhibit unexpected fluorescence in the absence of conventional chromophores, presenting potential applications in fluorescent anticounterfeiting. Thus, this work not only offers a strategy for designing multifunctional polyamides but also provides insights into the use of biomass resources in anticounterfeiting technologies.

Nuclear energy plays an increasingly pivotal role in meeting global energy demands. However, the discharge of radioactive iodine amid nuclear reactions brings about serious threats to environmental safety and human health. Therefore, striving to develop simple and efficient iodine capture materials is critically important. This study reports the design and synthesis of two electron-rich covalent organic polymers (COPs), TA-BP and TA-BT, for high-performance iodine capture. At 75 °C, TA-BP and TA-BT exhibited adsorption capacities for iodine vapor of 5.43 and 5.16 g g^–1, respectively. At room temperature, their maximum iodine adsorption capacities in cyclohexane solutions reached 1455.38 and 1399.77 mg g^–1, respectively. Both materials exhibited rapid adsorption kinetics for iodine vapor and liquid-phase iodine, outperforming most reported adsorbents. Furthermore, they possess excellent chemical stability and recyclability, demonstrating significant potential for complex application scenarios. Mechanistic studies reveal that the abundant electron-rich units and large electrostatic potential gradients in the materials’ frameworks induce electron-deficient I₂ to form polyiodide anions (I₃^– and I₅^–), which strongly interact with the COPs’ matrix, collaboratively enhancing the iodine capture performance. This research provides insights and guidance for the rational design of electron-rich covalent organic polymers with plentiful active sites, enabling highly effective iodine adsorption.

Vitrimers combine thermoset-like stability with thermoplastic-like reprocessability. Thiourethane polymers retain the advantages of classical polyurethanes while enabling efficient dynamic covalent bond exchange. We present a library of high-performance, recyclable thiourethane networks with tunable structure–property relationships and excellent shape-memory behavior. To improve recyclability, we introduce two key strategies: (1) covalently bonding the amine catalyst to an isocyanate group, which prevents catalyst leaching and ensures permanent recyclability; and (2) a reprocessing method that blends ground recycled material with uncured resin, followed by curing and compression under heat to restore mechanical and optical properties. Together, these approaches yield seamless, mechanically robust shape-memory polymer networks and support the sustainable design of smart materials with the potential for multiple life cycles and reduced environmental impact.

Though the growth of three-dimensional printing (3D printing) by vat photopolymerization has expanded opportunities for polymer manufacturing, most commercial resins are petrochemically derived and form thermosets that are challenging to recycle. We report the solvent-free synthesis of poly(β-methyl-δ-valerolactone) (PβMVL)-based photo-cross-linkable resins from the ring-opening polymerization of the renewable monomer β-methyl-δ-valerolactone (βMVL) with a low ceiling temperature (T_c) in the neat state. We explore the temperature dependence of the characteristic equilibrium monomer concentration and control the quantities of residual βMVL for sequestration with diamines to give diamidodiols or use as a nonreactive diluent to reduce resin viscosity. We demonstrate the advantage of diamidodiol cross-linkers in the presence of PβMVL to form a bimodal network strengthened with additional hydrogen bonding moieties, resulting in materials with tensile strengths of 8 ± 2 MPa and elongations at break of 105 ± 8%, which are comparable to commercial vat photopolymerization resins. High-resolution 3D-printed materials were produced and shown to be chemically recycled back to βMVL in high yield and purity.

Current research on conductive hydrogels for flexible wearable sensors has attracted significant attention, yet their practical applications face limitations. The balancing of mechanical properties and electrical conductivity remains the central obstacle─existing hydrogels cannot simultaneously achieve high strength, high conductivity, and rapid response. Herein, we fabricate a poly(vinyl alcohol) (PVA)-based conductive hydrogel with an ionic-electronic dual-conduction network through a method combining dehydration-induced densification with synergistic crystallization and salting-out aggregation followed by rehydration. This hydrogel exhibits exceptional mechanical properties: tensile strength of 34.216 MPa, fracture strain of 402%, elastic modulus of 16.18 MPa, and toughness of 76.77 MJ m^–3. Simultaneously, it demonstrated high electrical conductivity (3.7514 S/m). As a strain sensor, the hydrogel achieves three-stage high sensitivity (GF = 3.08–4.12), millisecond-level response (198 ms), and 500 cycle stability. It successfully monitors multijoint human motions (neck, elbow, knee, etc.), generating real-time signals synchronized with physiological deformations. This study presents a significant advance in mitigating the long-standing trade-off between mechanical robustness and electrical performance in conductive hydrogels through a rational ion–polymer interaction design.