Abstract Environmental concerns arise over traditional printed circuit boards (PCBs) due to the large amount of materials required for their production, which complicates their recyclability and degradability. In the transition toward low environmental impact materials, printed electronics (PE) allow the use of polymeric substrates, meeting eco-friendly criteria. In this context, six sustainable printable substrates have been prepared consisting of three carbon dioxide-derived polycarbonates (CO2–PCs) blended with degradable polymers. CO2–PCs are synthesized from the reaction between epoxide and CO2 offering an alternative and sustainable greener synthesis in contrast to bisphenol A polycarbonates (BPA-PCs). A selection process among the six substrates was conducted in order to determine the most suitable one for piezoresistive (PR) applications. Based on characterization results, the poly(ethylene)carbonate (PEC)/polybutylene succinate (PBS) blend, referred to as PEC 1, has emerged as the most appropriate candidate. The substrate exhibits a contact angle (CA) ≈ 61.4 ± 0.6°, a melting temperature (Tm) ≈ 89.1 °C, Young’s modulus (E) ≈ 88.8 ± 14.9 MPa, and a strain at break (εb) ≈ 946.6 ± 117.8%. On this substrate, 8- and 16-line strain gauges have been screen-printed using a water-based hydroxypropyl cellulose (HPC)/nitrogen-doped reduced graphene oxide (N-rGO) sustainable ink. The sensitivity of screen-printed gauges has been evaluated, where the 8-line strain gauge demonstrated higher linearity with electrical resistance variation under bending. As the printed substrates constitute the largest part of many sensors, this work contributed to the transition from petrochemical polymers to sustainable options in order to bridge the gap toward eco-friendly paths.
Abstract Machine learning (ML) is increasingly used to predict polymer properties, screen candidates, and monitor manufacturing. Yet many studies remain confined to direct repeat-unit-to-property or process-to-quality correlations, while explicit state variables are often predicted only as terminal targets, treated as parallel objectives, or invoked after prediction. Here, mediator-resolved cross-scale polymer machine learning is reserved for workflows in which a condensed-state or process-state variable is measured, predicted, or physically constrained and is used to connect upstream material identity or processing history to a downstream macroscopic response or decision. We organize the literature around four links: polymer identity and statistical chain structure; condensed-state and mesoscale organization; processing history; and macroscopic response. Rather than ranking methods by headline accuracy, we compare representation fidelity, data provenance, splitting strategy, uncertainty treatment, external or experimental validation, and reproducibility. The evidence indicates that repeat-unit representations remain useful for chemical-space screening but are insufficient for sample-specific predictions unless task-relevant information on molar-mass distribution, sequence, topology, preparation, and test conditions is included. Random splits often overstate generalization, and feature-attribution methods identify model correlations rather than mechanisms. Injection molding and extrusion are examined as detailed processing cases, with other routes considered to delineate common process–structure–property requirements. We conclude with priorities for metadata standards, multimodal benchmarks, uncertainty-aware physics-integrated models, and closed-loop validation. The resulting framework distinguishes mature interpolation tasks from genuinely transferable cross-scale design workflows.
Abstract Developing rigid polyurethane foam (RPUF) featuring well-balanced heat insulation, mechanical robustness, flame retardancy, and smoke inhibition properties through a halogen-free method is crucial for the advancement of building heat-isolated materials. In this study, a multi-component synergistic flame-retardant system was rationally constructed, consisting of Si/B ceramic precursors modified expandable graphite (EG-SB) and γ-aminopropyltriethoxysilane/phytic acid functionalized CeCoFe-LDH (LDH-SP), as well as ammonium polyphosphate (APP). Owing to the relatively low flame-retardant filler loading, the target RPUF composite retained an ordered pore structure with a low thermal conductivity of 0.028 W/(m·K). Besides, by virtue of the improved dispersibility of EG-SB and LDH-SP, the target RPUF composite exhibited desired compressive strength (0.21 MPa) and heat reliability (remaining char of 30.7 wt %). Benefiting from the remarkable cooperative flame-resistant effects of EG-SB, LDH-SP, and APP, the fire safety of the resultant RPUF composite was effectively enhanced (UL-94 V-0 grade; LOI value of 31.6%). Relative to pristine RPUF, the PHRR, THR, PSPR, and TSP parameters of the target RPUF composite decreased by 66.2%, 48.3%, 62.5%, and 92.9%, respectively, accompanied by significantly suppressed CO and HCN release. This work provides a feasible and viable route to fabricating high-performance RPUF thermal insulation materials with balanced comprehensive properties.
Abstract Hydrocarbon ionomers have emerged as promising per- and polyfluoroalkyl substance (PFAS)-free alternatives to perfluorosulfonic acid (PFSA) ionomers in proton-exchange membrane fuel cells. This study systematically examines hydrocarbon ionomer performance over a broad range of humidity and temperature conditions to identify the key challenges limiting commercial viability. The first challenge is the low water content per acid group at a given relative humidity, as hydrocarbon ionomers exhibit less swelling on an acid-normalized basis. The second challenge is the complexity of proton conduction pathways; analysis using percolation theory suggests that hydrocarbon ionomers exhibit significantly more complex conduction pathways than PFSA ionomers. The third challenge is proton transport activation energy, as determined by Vogel–Fulcher–Tammann analysis, which shows that hydrocarbon ionomers can achieve activation energies comparable to PFSAs, but only with specific ionomer architectures.
Abstract The domain-selective arrangement of biomolecules and cells at the microscale is essential for various biomedical applications. Recently, bio-conjugated polymer brushes have garnered immense attention from the research community. Several patterning techniques developed so far for producing microstructured biointerfaces based on polymer brushes suffer from various limitations, such as being time-consuming, costly, intricate processes created mostly for model inorganic substrates, etc. Herein, we present a simple method for creating micropatterned biofunctional brushes grafted on biodegradable polymer such as PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)). Oxygen plasma-assisted surface modification followed by domain-selective SI-ATRP (surface-initiated atom transfer radical polymerization) was carried out in tandem to create an alternate pattern of poly(ethyleneglycol)methyl ether methacrylate (PPEGMA) and poly(dimethyaminoethyl) acrylate (PDMAEMA) brushes on micropatterned PHBV surfaces. Thick dual brushes were selectively grafted onto their respective regions through a masking/demasking process, reaching approximately 965 ± 40 nm for PPEGMA and 1128 ± 50 nm for PDMAEMA under the optimized grafting conditions. Domain-selective proteins, gold nanoparticles, and aptamers were immobilized on a suitable brush, avoiding the production of micropatterned biointerfaces, which was ultimately explored for cancer (HeLa) cell immobilization, especially in aptamer-deposited regions. The scope of this innovation can be extended to the micropatterning of various biomolecules, including antibodies, bacteria, and DNA. The dual brush-grafted micropatterned biodegradable polymeric surface offers a straightforward way to immobilize biomolecules, which holds immense potential as a cancer diagnostic biosensor for enhanced and regiospecific bindings, while limiting nonspecific adhesion.
Abstract Sulfonated poly(ether ether ketone) (SPEEK) is a benchmark ionomer for nonfluorinated proton exchange membranes, yet its properties remain strongly dependent on the degree of sulfonation and relative humidity. In this work, SPEEK samples were synthesized using two distinct sulfonation routes: concentrated sulfuric acid (H2SO4) and a chlorosulfonic acid/dichloroacetic acid (HSO3Cl/DCA) system. The 2D homo- and heteronuclear NMR spectroscopy analysis of the resulting polymers, complemented by FTIR analysis, revealed that the sulfonation pattern strongly depends on both the reaction medium and the sulfonating agent. Sulfonation in concentrated H2SO4 predominantly produces monosulfonated (mono-regio) repeat units, whereas the homogeneous HSO3Cl/DCA medium promotes multi-regio substitutions. The corresponding membranes (≈15 μm thick) were cast, and their properties were studied. Compared with H2SO4-derived SPEEK, HSO3Cl/DCA-SPEEK membranes exhibited higher Young’s modulus, more pronounced yield behavior, and higher proton conductivity.
Abstract Selective NH3 removal from N2/H2-rich streams requires porous adsorbents with reversible and preferential NH3-binding sites. Herein, we report a carboxyl-functionalized pentiptycene-based nanoporous organic polymer (PNOP-1) prepared by one-pot Friedel–Crafts polymerization of pentiptycene quinone and pyromellitic dianhydride. The rigid pentiptycene scaffold creates permanent microporosity, whereas dianhydride-derived carboxyl/carbonyl groups provide additional interaction sites for NH3 adsorption. PNOP-1 adsorbs 10.4 mmol·g–1 NH3 at 298 K and 100 kPa, accompanied by substantially lower N2 and H2 uptake. Dry-gas breakthrough experiments, isosteric heat of adsorption, and molecular simulations suggest that micropore confinement together with favorable NH3–oxygen interactions contributes to the observed selectivity.
Abstract Ternary organic solar cells (T-OSCs) can mitigate the spectral and morphological limitations of binary blends, but the molecular requirements for effective polymeric guest donors remain insufficiently defined. Here, three composition-tuned, benzo[d][1,2,3]thiadiazole-containing wide-band gap terpolymers (F1–F3) were synthesized and evaluated as guest donors in PM6:Y6 devices. Varying the relative contents of the benzo[d][1,2,3]thiadiazole- and benzodithiophene-dione-derived segments modulates the absorption, frontier molecular orbitals (FMO), and blend compatibility. Among the series, F2 provides the most favorable combination of a deep highest occupied molecular orbital (HOMO) level, efficient exciton dissociation (98.8%), and balanced hole/electron transport (mobility ratio = 1.15). Its surface energy (22.7 mN m–1) lies between those of PM6 (20.6 mN m–1) and Y6 (27.4 mN m–1), while its comparatively low Flory–Huggins interaction parameter with Y6 (χ = 0.221) is consistent with improved interfacial mixing. Transmission electron microscopy and atomic force microscopy reveal a finer and more uniform blend morphology, supporting reduced recombination and improved charge collection. Consequently, PM6:Y6:F2 devices deliver a power conversion efficiency of 17.45%, compared with 16.19% for the binary PM6:Y6 control, through simultaneous increases in open-circuit voltage, short-circuit current density, and fill factor. These results demonstrate that terpolymer composition can be used to co-optimize electronic structure and interfacial compatibility, providing a practical route to polymeric guest donors for multicomponent organic solar cells (OSCs).
Abstract The practical application of self-assembled monolayers (SAMs) in inverted perovskite solar cells (PSCs) is severely hindered by insufficient substrate binding, inhomogeneous coverage, and limited defect passivation at the buried interface. Herein, we report the synthesis of poly{(2-(4,8-bis(3-(dimethylamino)propoxy)-6-(thiophen-2-yl)benzo [1,2-b:4,5-b′]dithiophen-2-yl)-7-(thiophen-2-yl)-9H-fluorene-9,9-diyl)[bis(hexane-6,1-diyl)]bis(phosphonic acid)}, a bisphosphonic acid–functionalized polymer, which was co-assembled with 4-phenyl-4-(4-(dicyanomethylene)-2-methyl-6-(pyridin-4-yl)-4H-pyran-4-ylidene)cyclohexanone, a conventional small molecule forming SAMs to fabricate a synergistic composite hole-transport layer. Based on a synergistic dual-site anchoring mechanism, the multidentate bisphosphonic acid groups strongly bind with the transparent conductive oxide substrate, while the sulfur atoms in the polymer backbone coordinate with undercoordinated Pb2+, mitigating interfacial ionic defects. The conjugated backbone facilitates rapid hole transport along the polymer chain, while co-assembly suppresses molecular aggregation, yielding a uniform, pinhole-free buried interface with enhanced wettability. Consequently, the optimized inverted PSCs exhibit a remarkable power conversion efficiency (PCE) of 24.23%, with a short-circuit current density of 24.85 mA cm–2 and high fill factor of 84.26%. The unencapsulated device maintains ∼80% of its initial PCE after 600 h of thermal aging at 80°C under a nitrogen atmosphere. This polymer-small-molecule co-assembly strategy offers a versatile route for developing efficient and stable inverted perovskite photovoltaics.
Abstract The rapid growth of modern electronics and 5G communication has created a strong demand for flexible electromagnetic interference (EMI) shielding materials; however, achieving high shielding effectiveness in polymer composites typically requires large amounts of conductive fillers, often at the severe cost of mechanical performance. To address this trade-off, a highly stretchable and self-healable polyurethane urea (PUU) composite film was developed by introducing amino-modified, silver-plated tetrapod zinc oxide whiskers (T-ZnO@Ag-NH2) as conductive fillers. The PUU matrix was deliberately constructed with dynamic disulfide bonds, reversible imine bonds, and multiple hydrogen-bonding interactions, which together imparted excellent toughness and intrinsic self-healing ability. Meanwhile, the T-ZnO fillers were modified through electroless silver plating followed by amino functionalization, thereby improving their electrical conductivity, dispersibility, and interfacial compatibility with the polymer matrix. The optimized composite containing 25 wt % T-ZnO@Ag-NH2 exhibited stable tensile performance, with a tensile strength of 8.7 MPa, while still maintaining effective self-healing behavior, reaching a healing efficiency of up to 70% at 60 °C. In addition, the composite film delivered an outstanding EMI shielding effectiveness of 49.57 dB in the X-band at a thickness of only 0.5 mm. Overall, this work provides an effective route for designing flexible, durable, and multifunctional EMI shielding materials, and also highlights their considerable potential in flexible electronics and wearable sensing devices.
Abstract The demand for flexible polyvinylidene fluoride (PVDF) sensors in underwater and wearable technologies is increasing due to their ability to maintain stable performance by adapting complex geometries and withstanding mechanical deformation. This study reports the use of a predictive model based on Machine Learning (ML) to develop highly piezoelectric thick PVDF sheets for hydrophone applications. A sustainable and scalable three-stage process comprising extrusion, controlled stretching, and high-voltage contact poling was used for preparing thin piezoelectric PVDF sheets. To identify the structure correlation with the stretching process, these were characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and quantification of the β-phase was performed using FTIR spectroscopy. In this study, five different machine learning models, viz., Gaussian process regression (GPR), support vector regression (SVR), random forest regression (RFR), artificial neural network (ANN), and genetic algorithm-optimized artificial neural network (GA-ANN) were developed using the outcome from the FTIR analysis of the stretched PVDF sheets. These models were used to predict the optimal stretching conditions to achieve the optimum β-phase content for thick PVDF sheets, which are required for specific applications. The statistical error analysis showed that the GA-ANN model had a higher generalization capability than the other models. The predicted conditions were experimentally validated and employed to develop thick PVDF sheets with high β-phase content. The highly piezoelectric form of the stretched PVDF sheet was obtained by high-voltage contact poling, with a high voltage coefficient (g33) of −300 ± 10 mVm/N. Finally, a prototype PVDF hydrophone was fabricated using the sheets developed with GA-ANN predicted conditions, and its underwater acoustic receiving sensitivity was tested. The hydrophone exhibited a flat frequency response of −204 ± 0.8 dB ref V/μPa in the frequency range of 1–10 kHz. This work demonstrates a promising method for integrating GA-ANN modeling with scalable PVDF processing for tailoring the piezoelectric properties and fabricating flexible underwater acoustic sensing systems.
Abstract Additive manufacturing of soft conductive materials enables flexible electronics, sensors, and robotic systems, yet is often constrained by high-temperature melt processing, postprint activation, or rigid conductive inclusions that reduce compliance. Here, we introduce a cold-extrusion strategy to create feedstock for liquid metal (LM)/thermoplastic elastomer composites that overcomes these limitations, enabling additive manufacturing of intrinsically conductive soft structures. By lightly solvating the polymer matrix, the composite enters a transient, putty-like processing state that enables extrusion without elevated temperature while preserving high LM loading (>60 vol %) and uniform droplet dispersion. Crucially, we leverage the high shear forces inherent to the extrusion process to drive droplet coalescence within the putty, directly forming a feedstock with a percolated, electrically conductive network. The continuously extruded LM/thermoplastic polyurethane feedstock is then pelletized and directly fabricated into multidimensional, conductive architectures using elevated-temperature extrusion-based 3D printing, without the need for thermal sintering, mechanical embossing, or secondary conductive inclusions. The printed composites reach notable conductivities of 0.4–1.8 × 104 S/m while retaining extensibility above 200% strain, demonstrating an additive manufacturing workflow that enables simultaneous printability, conductivity, and mechanical compliance. These results establish a general strategy for additive manufacturing of conductive thermoplastic elastomer composites for scalable fabrication of soft electronic and robotic systems.
Abstract Conventional transparent paper suffers from limited optical transmittance, poor water resistance, and low mechanical strength, and its fabrication typically depends on organic solvents, which cannot meet the long-term requirements of high-end packaging. In this work, we fabricated a biodegradable, highly transparent Carnauba wax/Waterborne Polyurethane (CW/WPU) composite paper via a green, solvent-free aqueous emulsion impregnation process using cellulose paper as the substrate, and systematically elucidated the synergistic mechanism among cellulose, CW, and WPU. The aqueous CW/WPU system uniformly disperses and infiltrates the paper pores, forming a dense, continuous structure (RMS = 7.31 nm) that suppresses interfacial light scattering and thus achieves a high transmittance of 87.79% at 550 nm. The continuous WPU network establishes strong interfacial adhesion and hydrogen bonds with the cellulose substrate, imparting excellent mechanical strength and toughness (tensile strength = 37.6 MPa). Meanwhile, the composite exhibits enhanced water vapor barrier performance (WVTR = 125.5 g/(m2·d)) while retaining biodegradability in natural soil. This entirely green, solvent-free strategy overcomes the optical, mechanical, and barrier limitations of conventional cellulose paper, providing a pathway to replace plastics in packaging for consumer electronics displays and protective equipment.
Abstract Adverse friction and wear between moving mechanical parts create safety risks by dissipating substantial energy and causing mechanical failure. The most common method for reducing friction and wear and improving energy efficiency is the lubrication of mechanical parts. However, conventional sulfur- and phosphorus-based lubricant additives have raised serious toxicological and ecological issues, which are incompatible with contemporary sustainable development goals. In this work, diethanolamine phenylborate (DEAB)-containing polymer micelles have been constructed in situ in a lubricating base oil via dative interactions (B–N) between diethanolamine-functionalized block copolymers and phenylboronic acid derivatives. The resulting polymer micelles have a poly(stearyl methacrylate) corona and a DEAB core, conferring long-term colloidal stability in the base oil. Ball-on-disc reciprocating tribological studies showed that the polymer micelles achieved a 52% reduction in friction coefficient (from 0.25 to 0.12) and an 89% decrease in wear volume (from 1.02 × 106 to 1.12 × 105 μm3) compared to the unmodified base oil. Moreover, the micelles exhibited high load-bearing capacity up to 1200 N, which was much higher than those of diethanolamine- (450–650 N) and boron-containing block or random copolymers (700–900 N) alone. This enhanced load-carrying capability was attributed to the in situ formation of B2O3 and h-BN at the rubbing steel interfaces via tribochemical reactions. This work provides a platform for developing environmentally friendly lubricant additives through rational combination of functionalized block copolymers and triboactive molecular units.
Abstract Photovoltaic (PV) encapsulants play a pivotal role in ensuring the long-term reliability of solar modules by protecting sensitive cells from moisture ingress, mechanical stress, and ultraviolet (UV) degradation. However, conventional encapsulant materials, such as ethylene-vinyl acetate, polyolefin elastomer, and polyvinyl butyral, exhibit several inherent limitations, including a high water vapor transmission rate, poor delamination resistance, and easy formation of optical haze under long-term UV irradiation in hygrothermal conditions. To address these challenges, we herein design a CO2-derived aliphatic polycarbonate-based thermoplastic polyurethane (TPU) as a PV encapsulant, which combines high transmittance (>90.5%), flexibility, superior water vapor barrier properties (WVP < 12.42 g·mm m–2 day–1), moisture insensitivity, and strong adhesion to PV glass and backsheet substrates. More specifically, the multiblock TPU is synthesized via the polyaddition of poly(propylene carbonate)diol, polyether diol, hexamethylene diisocyanate, and 1,4-butanediol. Upon optimizing the chemical composition and incorporating proper additives (e.g., silicone coupling agents, UV absorbers, antioxidants), the encapsulant achieves enhanced interfacial adhesion with a peel strength of 87.2 N cm–1 and maintains a residual peel strength of 73.4 N cm–1 following accelerated UV aging. Additionally, the adhesion mechanism based on TPU is proposed and preliminarily elucidated. This study tackles key challenges in photovoltaic module encapsulation by developing this high-performance alternative material, demonstrating significant potential for large-scale industrial applications.
Abstract The valorization of whey, the main byproduct of cheese manufacture, is hindered for small and medium-sized dairy enterprises (SMEs) by the high cost of conventional separation technologies such as membrane filtration and chromatography. In this work, complex coacervation between whey proteins and carboxymethylcellulose (CMC) was scaled from 5 to 100 L to develop a simple, low-cost process for recovering a protein- and lipid-enriched product. Five commercial CMCs with molecular weights ranging from 18 to 780 kDa were first evaluated at laboratory scale. Intermediate-Mw CMC (400 kDa) provided the best balance between electrostatic complexation and sedimentation, removing 99% of the initial protein from the supernatant, as confirmed by residual protein quantification and turbidity. Using the selected CMC, the process was successfully scaled to 100 L in a conical-bottom tank with an off-centered 45° four-blade turbine. Geometric similarity (H/Dt = 2.0–2.5, Da/Dt = 0.26–0.33) was applied, achieving fully turbulent flow at both scales (Re = 3.56 × 104 and 1.41 × 105). Protein recovery reached 76%, with a 3.4-fold concentration of proteins and nearly complete fat recovery in the coacervate. The freeze-dried coacervate was readily redispersible up to 20% (w/v). Its ζ-potential shifted from near-zero at pH 3 to −40 mV above pH 6, reflecting the combined contribution of whey proteins and residual CMC. Thermal gelation of the coacervate (3.1% protein) was strongly pH-dependent: weak gels formed at acidic pH (G′ = 6–23 Pa), while strong, cohesive gels developed at alkaline pH (G′ = 325 Pa at pH 9). The lactose-rich supernatant showed reduced COD and BOD loads (12% and 28% reduction, respectively) and was successfully fermented by kefir grains without nutrient supplementation. This scalable, food-grade coacervation process offers an accessible alternative for dairy SMEs to transform whey from an environmental burden into a functional ingredient.
Abstract Addressing the critical issues of inevitable agglomeration and unsatisfactory photocatalytic efficiency inherent to powdered photocatalysts during water treatment, the idea to develop a robust nanofiber membrane carrier that can achieve uniform loading of photocatalysts and enhance their activity is valuable. The modified polyacrylonitrile (P-CPAN) was synthesized first by pomegranate peel carbon dots (PCDs) with acrylonitrile (AN) and acrylic acid (AA) through the in situ polymerization, then the hierarchical composite membrane, i.e., TP/CT@P-CPAN, was fabricated via electrospinning followed by a subsequent preimpregnation/solvothermal synthesis method. Compared with the reference sample, i.e., titanium dioxide (CT) powder, the heterojunctional TiO2@PCDs (TP) powder formed by the combination of TiO2 and PCDs has better photocatalytic ability, as TP could significantly expand the light absorption range to the visible-light region and reduce the recombination of photoinduced electron–hole pairs. Both PCDs and −COOH groups on the surface of P-CPAN nanofibers were suitable anchor points for amorphous CT during preimpregnation, TP and CT crystals through solvothermal synthesis could then attach firmly on the membrane. Hence, the TP/CT@P-CPAN membrane demonstrated good photocatalytic performance and durability. Even after 4 h of ultrasonic treatment, no significant shedding of the supported photocatalyst was observed. It can remain relatively stable even under acidic (pH = 2), alkaline (pH = 12), and high-salinity (10 g·L–1) conditions. Research on this kind of TP/CT@P-CPAN material that can be applied to complex usage environments has certain reference value for the development of fiber membrane-based photocatalyst materials.
Abstract Organ-on-a-chip (OOC) systems rely on membrane-supported tissue interfaces to replicate organ-level barrier functions in vitro. However, conventional porous membranes often provide limited biological cues for cell adhesion and may require an extracellular matrix coating. Here, we developed core–shell nanofibrous porous membranes via coaxial electrospinning, using polycaprolactone (PCL) as the structural core and gelatin as the bioactive shell. These membranes were integrated as replaceable inserts into a commercial dual-channel intestinal chip. Using identical chip geometry and membrane material, we compared three culture regimens: static culture, gravity-driven oscillatory flow, and continuous low-shear perfusion. The C-PCL/Gel membrane exhibited suitable mechanical stability, hydrophilicity, cytocompatibility, and cell-adhesion performance for epithelial–endothelial coculture. In the intestinal barrier model, continuous low-flow perfusion yielded the most favorable outcomes, including transepithelial electrical resistance (TEER) values exceeding 500 Ω·cm2, reduced tracer permeability, more continuous zonula occludens-1 (ZO-1) junctional staining, denser F-actin networks, and altered mucin 2 (MUC2) distribution. These improvements likely arise from combined effects of continuous medium renewal, enhanced mass transport, waste removal, and low-level hydrodynamic stimulation. This membrane-integrated chip provides a practical platform for studying intestinal barrier formation under different fluidic regimens, offering a biomimetic alternative to conventional membrane interfaces.
Abstract All-polymer photodetectors, owing to their remarkable advantages of flexibility and mechanical durability, exhibit demonstrated potential for application in the field of wearable technology. Nevertheless, the frequently employed double-component active layer structure is susceptible to performance degradation during long-term use. Consequently, a copolymer PM6-co-TTY6 possessing both donor and acceptor properties was designed and synthesized. The single-component active layer devices based on PM6-co-TTY6 exhibit pronounced photomultiplication characteristics. The maximum external quantum efficiency (EQEmax) of PM6-co-TTY6 device with thin active layer reaches 365% or 336% under a bias voltage of +5 V or −5 V, respectively. Remarkably, the device shows bias-tunable spectral response with increasing active layer thickness: a narrowband response (800–900 nm) with a EQEmax of 25% and a narrow full width at half maximum (FWHM) of 30 nm under negative bias, while a broadband response (300–900 nm) under positive bias. At this stage, the device can be switched between broadband and narrowband detection modes by reversing the polarity of the applied bias.
Abstract To enhance the gas separation performance of polyimide membranes, the synergy of thermal rearrangement (TR) and in situ decarboxylation crosslinking represents a distinctive fabrication strategy. Herein, a diamine monomer functionalized with both carboxyl and hydroxyl groups, namely 2-(3,6-bis(4-amino-3-hydroxyphenoxy)-9H-xanthen-9-yl)benzoic acid (BAHXBA), was synthesized. This diamine was then copolymerized with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) at varying molar ratios. A set of polyimide (PI) membranes, designated as PI(BAHXBA-6FAP), were fabricated via thermal imidization at 300 °C, followed by annealing at 450 °C to construct thermally rearranged membranes, TR(BAHXBA-6FAP). The high-temperature thermal treatment induces in situ benzoxazole cyclization and moderate crosslinking derived from side-chain carboxyl decarboxylation. The copolymer composition effectively tunes chain-stacking distance and thermal properties: elevated 6FAP content increases d-spacing, and higher thermal treatment temperature also leads to a noticeable increase in d-spacing. For the TR(BAHXBA-6FAP) membrane with a BAHXBA-to-6FAP molar ratio of 5:5, gas permeability coefficients reach 1177 (H2), 341 (O2), 1116 (CO2), 51 (CH4) and 43 (N2) Barrer. Its ideal H2/N2 selectivity exceeds the 2008 Robeson upper bound, and the O2/N2 selectivity surpasses the corresponding 2015 upper bound. This work provides a facile structural tailoring strategy via coupled thermal rearrangement and decarboxylation crosslinking for high-performance polyimide separation membranes.
