ACS Applied Polymer Materials最新文献

Highly elastic porous sponges exhibit tremendous application potential in various fields due to their adjustable characteristics. However, the liquid nature of silicone precursors presents challenges in the fabrication of three-dimensional (3D) structures. In this study, highly elastic three-dimensional porous polydimethylsiloxane (PDMS) sponges were successfully fabricated using a zero-pollution, cost-effective direct ink writing (DIW) technique, combined with NaCl template leaching. The resulting sponges exhibit remarkable supercompressibility, with negligible stress loss (approaching zero) under 80% cyclic compression, outstanding cyclic durability, and exceptional superhydrophobicity, as evidenced by a static contact angle of 164.4°. Furthermore, they demonstrate the ability to selectively adsorb oil slicks on water surfaces and heavy oils submerged underwater, with the added benefit of being reusable. This study demonstrates that the integration of direct ink writing and salt template leaching offers an effective strategy for fabricating highly complex, three-dimensional porous PDMS sponges, enabling the tailored design of highly elastic structural materials.

Aerogel fibers have attracted considerable attention due to their lightweight, stitchability, and heat-insulating properties, which are promising for wearable insulation applications. However, there is still a lack of a facile method to continuously spin high-performance aerogel fibers with uniform structure and excellent thermal/mechanical properties. This paper reports a continuous spinning of heterocyclic aramid aerogel fibers (HAAFs) by combining the principles of hydrochloric acid (HCl)-induced protonation and heat-induced reduction of solvation. The protonation of the benzimidazole ligand contained in the polymer backbone weakens the dissolving capacity of the polymer and extends the conformation of polymer chains, resulting in ordered and liquid-crystal-like aggregation structures, as evidenced by the increased birefringence in organogels, which is beneficial to improve the intermolecular interactions and strengths of gel networks. Heating of the solidification bath during spinning further reduces the solvation of the polymer and enhances the interaction between HCl and benzimidazole ligands, which strengthens the cross-linking network and forms robust gel fibers. The subsequently obtained HAAFs demonstrate a uniform porous structure, low thermal conductivity, high mechanical properties, high thermal stability, and good flame retardancy, making them good candidates for high-temperature thermal insulation applications. In addition, the HAAFs are also recyclable due to their reversible intermolecular interactions. This study is expected to provide an effective strategy for the design and large-scale manufacturing of aramids and other high-performance aerogel fibers.

Responsive photonic crystal materials that can change their structural color in response to external stimuli have attracted growing attention in the research area of flexible electronics. This study presents a conductive structural color hydrogel film featuring an inverse opal structure designed for use in wearable sensors. The hydrogel film consists of a double-network structure, where the first network is formed by acrylic acid and acrylamide (P(AA-co-AM)), and the second network is composed of quaternized chitosan. By incorporating multiwall carbon nanotubes (MWCNTs) into the hydrogel, not only is the conductivity enhanced but also the tensile strength of the hydrogel is significantly improved (0.45 MPa). Due to the excellent stretchability and inverse opal architecture of the hydrogel matrix, the film exhibited vibrant and tunable structural colors in response to applied stress or strain. Leveraging these attributes, the hydrogel film not only visualized color changes but also provided feedback on electrical signals in response to strain or stress stimuli, thereby functioning as a dual-signal soft sensor for the real-time monitoring of optical and electrical signals related to human motion. In addition, the presence of chitosan, known for its excellent water absorption properties, allows the film to swell in water while shrinking in ethanol. This characteristic enables the film to quantitatively respond to ethanol through noticeable color changes. This work demonstrates a strategy of synergistic enhancement of the mechanical properties of hydrogels through a combination of MWCNTs and a double-network structure. The presented conductive structural color hydrogel film, featuring a dual-signal output, exhibits remarkable potential for applications in wearable devices and multifunctional sensors.

Thin-film transistors (TFTs) using 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic small-molecule semiconductors represent a significant advancement in the field of organic and flexible electronics. Their high charge carrier mobility, solution processability, and tunable electronic properties make them highly suitable for diverse device applications. In this study, we report the effects of nonorthogonal solvents on the performance of C8-BTBT TFTs by exploring the functional impact of the choice of gate dielectric and device configuration. By considering the crucial semiconductor/dielectric interface effect for developing operational TFTs, we investigated different C8-BTBT TFTs gated by oxide, solution-processed polymer, and polymer electrolyte gate dielectrics. The optimized devices achieved varied charge carrier mobilities between 10^–3 and 18 cm² V^–1 s^–1, which were within the reported mobilities for C8-BTBT TFTs in the literature. This work provides a practical insight into nonorthogonal solvent effects and lays a foundation for developing high-performance TFTs and electronic devices using organic small-molecule semiconductor materials.

The advancement of ecofriendly and high-performance energy transformation systems has driven the development of advanced membrane materials for alkaline water electrolysis (AWE), which conduct hydroxide ions and block the interpenetration of hydrogen and oxygen. The wettability and inadequate gas blocking remain challenges for the AWE membrane. In this study, a hydrophilic polyphenylene sulfide/cellulose/polyphenylene sulfide (PPS/C/PPS) composite membrane with high bubble point pressure (BPP), outstanding oxygen purity, and low area resistance (AR) was fabricated. The porous PPS/C/PPS membrane exhibits a high BPP of 12.4 bar and low AR of 0.014 Ω·cm². Notably, gas purity tests reveal that the oxygen purity is about 99.974%, which is much higher than that of commercial hydrophilic polyphenylene sulfide (C-HPPS) (98.5%). The AWE cell with the PPS/C/PPS composite membrane shows a current density (CD) of 319.2 mA·cm^–2 in 30 wt % KOH solution at 80 °C at a voltage of 2 V, surpassing that of C-HPPS (208.0 mA·cm^–2). Additionally, the AWE cell exhibits high stability of more than 450 h at KOH solution (30 wt %) without attenuation, emphasizing the membrane’s competitive edge and its vast application potential.

For industrial-scale additive manufacturing (AM) to be successful, the adoption and innovation of sustainable materials made from biobased and renewable resources is vital. Herein, we explore the potential of using waste cork particles as a high-volume filler in nylon-12-based thermoplastic composites, with processing and performance characteristics optimized for fused filament fabrication (FFF) to create customized, lightweight engineered products. To generate engineering thermoplastic composites for FFF, we modified the cork with a silane coupling agent and melt-mixed it with nylon-12. A thorough evaluation was conducted on the impact of the volume fraction of the surface-modified cork filler on the viscoelastic and processing characteristics of the polymer melt. Using the optimized composition, filaments for 3D printing by FFF were produced, and their properties including thermal stability, crystallization behavior, filament extrusion morphology, and mechanical properties were evaluated. Scanning electron microscopy (SEM) was used on the tensile-fractured surface of the failure specimens to understand the mode of failure and correlate it with strength. Micro-CT was used as a nondestructive test to study the distribution of cork in the filament and the 3D-printed products. The surface roughness of the 3D-printed product was evaluated through digital microscopy. It was observed that (3-aminopropyl)triethoxysilane is an effective interaction promoter for nylon-12/cork composites. The melt rheology of nylon-12 and its composites exhibits non-Newtonian shear-thinning behavior and thermorheological complexity, with higher cork content further enhancing such shear-thinning characteristics. Considering processability, 3D printing capabilities, and final properties, a ∼15 vol % cork content was observed to be optimal. It has been confirmed that 3D-printed nylon-12/cork composite products can offer superior mechanical properties, flexibility, and elongation at failure compared to compression-molded samples. This study provides valuable insights into the composite’s feasibility for 3D printing and its potential applications.

Biomimetic construction of structural colors on materials as an environmentally friendly coloring method has received more and more attention. If the structural color of the materials has special functions, it will broaden the application field. However, functional structural colors are usually prepared through the coassembly of building units with functional agents or functional modification of structural colors. In this study, poly(2,2,3,4,4,4-hexafluorobutyl acrylate/methyl methacrylate/[3-(methyl acrylamide) propyl] trimethylammonium chloride) (PAMM) microspheres containing hydrophobic and antibacterial functional groups were prepared, which were used to construct multifunctional structural colors on black polyester fabrics through the atomization deposition method. PAMM microspheres with different particle sizes (332.1, 318.3, 302, 289.9, 257.2 nm) were successfully prepared by adjusting the amounts of monomers in the synthesis reaction, which can form different structural colors of pink, green, cyan, blue, and purple on the polyester fabrics. The fabrics with structural color can significantly inhibit the growth of E. coli and S. aureus, and the antibacterial rates of both are greater than 94%. The fabrics with structural color showed outstanding hydrophobicity with a static water contact angle greater than 140°. This research provides an idea for the preparation of multifunctional fabrics with structural colors through the synthesis of building units of polymer microspheres with multifunctional groups.

Vat photopolymerization (VP) is a powerful additive manufacturing process to produce high-resolution 3D objects from liquid photocurable resins, but the mechanical performance of its standard materials restricts its use in high-demanding applications. In this study, graphene oxide (GO), a widely investigated nanomaterial, was surface-functionalized by grafting the sustainable and photocurable poly(butylene itaconate-co-adipate) (PBIA) polyester to address these limitations. The covalent grafting of PBIA significantly improved the colloidal stability and dispersibility of GO in photocurable formulations, eliminating the need for extensive homogenization during the formulation of the nanocomposite resin. PBIA-coated GO (GO@PBIA) was easily miscible with VP resins, enabling the fabrication of 3D-printed nanocomposites with superior mechanical properties. At low filler concentrations (0.05 wt %), the GO@PBIA composites increased their elastic modulus up to 57% and tensile strength up to 100% compared to the base polymer, outperforming analogous composites prepared with unmodified GO. Surface modification also enhanced the deformability of the matrix, making these composites suitable for applications under tensile and flexural loads. Optical and morphological analyses confirmed the homogeneous distribution of GO@PBIA within the polymer matrix, demonstrating improved filler–matrix interactions, while electrical conductivity measurements proved that the surface modification approach proposed does not affect the conductive conjugated π system of the nanomaterial. This work highlights the potential of polymer-grafted GO as a multifunctional nanofiller to enhance the mechanical properties and processability of VP-based materials, paving the way for their use in high-performance applications.

Herein, an effective design strategy is utilized to simultaneously reduce two difficult-to-reconcile indexes in polyimide (PI): the dielectric constant (D_k) and dielectric loss (D_f). It is realized by the synthesis of cross-linked PIs using a bulky and cross-linkable diamine, (4,4′-(4-(4-(2,3,5,6-tetrafluoro-4-vinylphenoxy)phenyl)pyridine-2,6-diyl)dianiline) (TFVPPDA), featuring bulky triphenylpyridine and cross-linkable tetrafluorostyrol pendant groups. And copolymerized with 2,2′-bis(trifluoromethyl)benzidine (TFDB) and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) to synthesize cross-linkable PIs (co-FPIs: co-FPI-10, co-FPI-20, and co-FPI-30) with varying TFVPPDA content. Then, cross-linked PIs (co-FPIs-CL: co-FPI-10-CL, co-FPI-20-CL, and co-FPI-30-CL) were obtained by thermal cross-linking reactions. The cross-linked PIs with cross-linked networks possess more free volume compared with the corresponding uncured PIs, thus further reducing the D_k. Additionally, cross-linked networks restrict the deflection of polar imide groups in the polymer chain, leading to a relatively low D_f. More importantly, this design strategy effectively retains the excellent thermal, mechanical, and low moisture absorption properties of the PIs. Notably, co-FPI-30-CL has a low D_k (2.50) and D_f (0.0060) at a high frequency of 10 GHz, a glass transition temperature (T_g) of 384 °C, a 5 wt % decomposition temperature (T_d5%) of 566 °C, a low coefficient of thermal expansion (CTE) of 41.5 ppm/°C, a high tensile strength (σ_max) of 123.3 MPa, and a low moisture absorption rate (W_a) of 0.11%.

In this study, cellulose acetate (CA)-based polyamide (PA) nanofiltration membranes (CA-NF-2/0.4) with enhanced antifouling and separation performance were prepared through the interfacial polymerization of diethylenetriamine (DETA) and 1,3,5-benzenetricarbonyl chloride (TMC) for the effective removal of dyes and salt ions. Benefiting from the three reaction sites (primary and secondary amino groups) of DETA, a PA layer with a three-dimensional network structure formed on the CA substrate, imparting the CA-NF-2/0.4 membranes with a strong negative charge (−24.8 mV at pH 7) and a defect-free morphological feature. Consequently, the CA-NF-2/0.4 membranes exhibited high removal efficiencies for various dyes (99% for Rose Bengal and Congo Red, 95.5% for Methyl Orange, and 96.1% for Methylene Blue), as well as various monovalent and divalent salts, including MgCl₂ (84.2%), Na₂SO₄ (92.7%), MgSO₄ (91.8%), and NaCl (54.1%). Additionally, the CA-NF-2/0.4 membranes demonstrated excellent antifouling properties [the flux recovery ratio (flux recovery rate > 98.5%), long-term durability, and stability under high operational pressures and salt concentrations] due to their good hydrophilicity (water contact angle of 39.8°) and the hydrogen bonding interaction between the active amine groups of DETA and the –OH groups of the CA support layer. This study presents an effective method for fabricating cellulose-based NF membranes with high separation and antifouling performance, offering insights into the high-value utilization of cellulose-based materials.