ACS Applied Polymer Materials最新文献

Chronic wound management is an enormous challenge worldwide, resulting in a significant financial burden on the government. Among the treatment strategies for chronic wounds, wound dressings are a key component of the management and healing process. Conventional wound dressings are monofunctional and frequently demonstrate clinical limitations, including tissue adhesion issues and poor microenvironment regulation. In contrast, emerging innovative dressings represent a paradigm shift through their stimuli-responsive architectures that enable the real-time monitoring of wound parameters and adaptive therapeutic interventions. In particular, multifunctional wound dressings (typically as hydrogels and nanofibers) based on biopolymers have attracted much attention for chronic wound treatment. Several reviews on functional wound dressings for the treatment of chronic wounds have been published, usually devoted to a specific type of material (e.g., chitosan) or a single function (e.g., antimicrobial). However, an up-to-date review of multifunctional wound dressings based on nanostructured biopolymers (typically as hydrogels and nanofibers) is still lacking. This review highlights the latest advances since 2020, delving into the integrated design strategies, unique action mechanisms, and specific applications of these dressings in accelerating chronic wound healing. It also examines current research challenges and outlines future directions, aiming to provide insights that advance the clinical translation of next-generation, smart wound dressings.

Under low-carbon policies, green biodegradable materials such as okra polysaccharide (OP) and poly(vinyl alcohol) (PVA) have gained prominence. In this study, flexible PVA/OP/CA/CB (POAB) composite films are prepared via a simple one-pot method using citric acid (CA) as a cross-linker and carbon black (CB) as a filler. At a safe voltage of 6 V, the surface saturation temperature of the POAB composite films reaches 50 °C, making it a viable option for flexible electric heating devices to help patients alleviate joint pain and stiffness. At a light power density of 1.1 W/cm², the POAB composite films exhibit a surface saturation temperature as high as 140 °C, demonstrating outstanding photothermal conversion performance. As a wearable strain sensor, POAB composite films feature a wide response range (125%) and excellent cyclic stability (700 s), enabling the monitoring of the range of motion across different joint areas. This assists physicians and rehabilitation therapists in evaluating patients’ recovery progress. Furthermore, after 28 days of biodegradation in soil, it retains its structural integrity with outstanding stability. In summary, POAB composite films enable simultaneous management of the Joule heating effect, photothermal conversion, and wearable strain sensing, contributing to sustainable energy development.

Qualitative and quantitative analysis of fibers play an important role in the current textile industry, especially in the field of materials that are increasingly seeking fiber-reinforced composites; accurate qualitative and quantitative analysis is fundamental work. This work analyzes the dissolution and precipitation mechanisms of polyamide fibers in hydrochloric acid and their key features, which support more precise qualitative and quantitative analysis in relevant domains. By using a spectrophotometer (680 nm) combined with different proportions of chemical reagents, the dissolution and precipitation characteristics of polyamide in hydrochloric acid solution can be accurately characterized. The working curve is constructed based on linear correlation (with a regression coefficient of determination greater than 0.99), enabling accurate quantification . In addition, it was found that this technique has broad applications in the field of criminal investigation (Zughaibi, T. A.; Steiner, R. R. Analysis of Polymeric Carpet Fibers Using Direct Analysis in Real Time Coupled to an AccuTOF Mass Spectrometer. Polymers, 2021, 13, 16, 268−1920. 10.3390/polym13162687.), where it can be applied to the qualitative and quantitative analysis of nanogram samples. It also has the potential to be used in the field of sustainable development.

Viscosity modifiers (VMs) are widely applied in lubricants. Advanced VMs can modulate viscosity in response to various stimuli, such as pH, light, salinity, and temperature. This article explores comb-shaped macromolecules that exhibit thermoresponsive behavior, with potential applications as oil additives for use in transportation. Copolymers were prepared by free-radical polymerization of up to four methacrylate-based monomers with different polarities into sparsely branched comb-shaped macromolecules. The side chains of the comb comprised hydrogenated poly(butadiene), whereas the backbone contained lauryl, benzyl, and butyl methacrylates. Rheological measurements of concentrated solutions in a Yubase oil revealed an initial increase followed by a decrease in viscosity as temperature was increased from 25 to 105 °C. The magnitude of this effect was dependent on the concentration, between 10 and 20 wt % polymer, and the fraction of benzyl methacrylate versus butyl methacrylate in the copolymers. Cryogenic transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS) revealed polymer aggregates at low temperatures, which first swelled and then dissolved as individual solvated molecules on heating. This aggregation-expansion-dissolution phenomenon qualitatively accounts for the changes in viscosity.

Thermally stable polymers are essential for many high-performance applications, yet traditional experimental methods for studying stability are material-intensive, while machine learning models remain limited by the scarcity of reliable degradation data. We hypothesized that computational small-molecule kinetics could bridge this gap owing to the local character of degradation initiation and the ease of collecting data for molecular systems. To test this hypothesis, we curated computational kinetic data and developed models trained exclusively on small molecules to predict the relative thermal stability rankings of polymers containing C, H, O, N, F, and Cl. Experimental degradation data from 41 common polymers and ∼7k small molecules were used to benchmark the ability of small-molecule kinetics to predict polymer behavior without additional training data. All of the resulting models show remarkable transferability between the small-molecule results and polymer degradation metrics. We find that, while chemically diverse training data generally improve predictions, the accuracy of the underlying small-molecule kinetics is also crucial for maximizing transferability to polymer predictions. Notably, models trained on higher-quality alkane data with consistent kinetic parameters perform comparably or better than those trained on more diverse but incomplete data sets for certain polymer predictions. This suggests that accurately capturing fundamental degradation mechanisms in simple systems may be more valuable than incorporating diverse but potentially inconsistent chemical data. These results underscore significant opportunities for training accurate stability models that can be used for early-stage material design.

Polymers, particularly in laminated packaging, play a crucial role in preserving product quality and shelf life in the food and cosmetic industries. However, the widespread use of multilayer packaging, which consists of polyolefins and aluminum, poses significant recycling challenges. This study investigates the mechanical recycling of postconsumer multilayer packaging through cleaning and size reduction to obtain micron-sized aluminum-containing particles, which are used as additives. These particles are compounded with neat polypropylene in a twin-screw extruder and subsequently employed as feedstock for injection molding. This additive has dual functionality, serving as both a metallic pigment and an ultraviolet (UV) protective additive for injection-molded PP parts. The mechanical properties of the recycled composite, including tensile strength, elastic modulus, and ductility, were quantitatively comparable to those of neat PP, with an elastic modulus of approximately 1.9 GPa and a maximum tensile stress close to 38 MPa for particle contents between 15 and 25 wt %. These properties remained essentially unchanged with respect to neat PP, indicating no major loss in structural integrity. Fracture tests revealed that composites containing recycled particles behaved in a more ductile manner than neat PP, exhibiting larger deformation capability. An increase in fracture toughness of PP was observed when recycled particles were incorporated into PP (from 40.5 N·mm^–1 to ∼50 N·mm^–1) with no significant differences among composites with varying particle content. UV degradation tests showed that recycled aluminum particles provide moderate resistance to oxidation, delaying carbonyl group formation. This study confirms the feasibility of transforming postconsumer multilayer packaging waste into sustainable composite materials, supporting circular economy initiatives.

High-performance waterproof-breathable nanofibrous membranes are critically needed for wearable applications, yet their development faces persistent challenges including the reliance on fluorinated compounds, the inherent trade-off between waterproofness and moisture permeability, and the insufficient mechanical durability under dynamic conditions. Herein, a fluorine-free silica nanofiber/waterborne polyurethane (SiO₂/WPU) composite membrane was prepared via electrospinning and WPU dipping, which features a hierarchical “SiO₂ nanofiber skeleton-WPU coating” structure. This design integrates a hydrophilic and moisture-absorbing SiO₂ scaffold with a discontinuous stretchable WPU layer, endowing the SiO₂/WPU composite membrane with a hydrophobic surface (127.07° water contact angle) while retaining high moisture regain (10.23%), together with a hydrostatic pressure of 3.96 kPa and a water vapor transmission rate of 4.14–5.23 kg m^–2 day^–1, achieving simultaneous waterproofness, moisture permeability, and moisture absorption without the use of fluorinated chemicals. The SiO₂/WPU composite not only overcomes the waterproofing limitations of conventional fluorine-free materials but also attains a comfort level that surpasses most synthetic materials and approaches that of natural cotton. Mechanically, it possesses a tensile strength of 9.39 MPa, an elongation at break of 8.17%, and endures over 120,000 bending cycles, bridging the gap in mechanical endurance for flexible waterproof nanofibrous membranes. This work provides an eco-friendly and structurally innovative pathway to high-performance wearable textiles with enhanced wearing comfort.

The proton exchange membrane (PEM) is a critical component of proton exchange membrane fuel cells (PEMFCs), for which its durability and performance are of paramount importance. This study presents a series of four-armed, star-shaped branched polymers (SPTP-T_x) with tunable branching degrees, synthesized via a straightforward two-step method, for application in PEMFCs. The branching moiety, tetraphenylethylene (TPM), imparts an increased free volume and a well-defined microphase-separated structure to the polymers, enabling a high proton conductivity of up to 195 mS cm^–1 at 80 °C. Furthermore, the multiple branching sites in TPM monomers facilitate an increase in the polymer’s weight-average molecular weight to 113 kg mol^–1, which in turn yields a high tensile strength of 67.3 MPa. The membrane also demonstrates outstanding oxidative stability, retaining over 77.2% of its mass after 12 h of immersion in Fenton’s reagent at 68 °C. In H₂/air fuel cell tests, the membrane electrode assembly (MEA) based on SPTP-T_0.10 exhibits a very low hydrogen crossover flux of 1.46 × 10^–9 mmol cm^–2 s^–1 yet achieves a high peak power density of 648 mW cm^–2, both values being markedly superior to those of the linear SPTP membrane. Furthermore, during a 100 h accelerated stress test at 80 °C and 30% relative humidity, the open-circuit voltage (OCV) decay rate was only 0.667 mV h^–1. This work demonstrates that incorporating TPM as a branched unit is an effective strategy for enhancing the critical PEM properties, including oxidative stability and proton conductivity, offering valuable insights for developing high-performance PEMFCs.

A polyimide-based supramolecular system including an azo component, namely, 4-[(4-cyanophenyl)diazenyl]phenol, was tested regarding its photomechanical and piezoelectrical behavior. According to theoretical calculations, the polymer system exhibits a significant internal free volume (15.7%), suggesting a molecular rearrangement capacity that can sustain the trans–cis isomerization. Photoactuation tests performed under moderate intensities of an unpolarized light from XeCl excimer laser irradiation revealed a peak bending angle of 24° after 7 min at 30 mJ/cm². When the laser fluence was doubled, the bending angle increased to 34° within 30 s and eventually exceeded 60° after 7 min. They induced only physical changes in the molecular structure of the polyimide, with no chemical modifications being detected. Porous, ordered structures with depths of ∼700 nm and 1.2 μm, similar to “honeycomb” formations, appeared on the surface of the photoactuated films, compared to the initial relatively uniform surface, increasing their roughness. The evolution of the texture parameters was an indicator of the formation of 3D spatial structures with high complexity due to physical phenomena that occurred during laser irradiation, such as photoinduced structuring, localized thermal expansion and internal stress, or Marangoni currents. The piezoelectric constant d33 of the pristine sample attributed to the presence of highly polarizable −CN groups within both the main chain and the azo component was improved after the photoactuation tests, facilitated by the orientation of the azo group dipoles and a slight relaxation of internal stresses. These properties recommend this multifunctional material for applications in smart devices as wireless actuators.

In recent years, textile-based colorimetric sensors prepared based on photonic crystals (PCs) structural colors have received more and more attention. However, the development of textile-based colorimetric sensors with multifunctionality is still a challenge. In this study, multifunctional textile-based colorimetric sensors were developed by introducing an innovative PCs system that integrated water-responsive and antimicrobial properties. Novel poly(styryl-tert-butyl acrylate-[3-(methylacrylamide) propyl] trimethylammonium chloride) (PSTM) microspheres containing quaternary ammonium salt groups were synthesized. These microspheres were then utilized to create a textile-based PCs colorimetric sensor that exhibits antimicrobial activity. The particle sizes of the synthesized PSTM microspheres were effectively controlled (353.1, 301.1, 271.5, 263.2, and 242.6 nm) by regulating the monomer mass ratio. As the microsphere particle size decreased, the structural color generated after their atomization and deposition on the fabrics exhibited a blue shift, transitioning sequentially from brownish yellow and green to cyan, blue, and finally purple. These textile-based colorimetric sensors with different structural colors showed fast (less than 2 s) and reversible responses to water, and they also responded to different levels of water content and ethanol solution concentration. These textile-based colorimetric sensors had excellent response stability and could be reused more than 500 times. They also showed excellent antimicrobial properties against E. coli and S. aureus, with antimicrobial rates both greater than 99%. This integrated multifunctional textile-based colorimetric sensor with tunable structural color, rapid water sensing, and inherent antimicrobial function offers a promising strategy for applications such as water content monitoring in medical health, sports fitness, and infant care.