Chinese Journal of Polymer Science最新文献

Moderate ultraviolet (UV) radiation from sunlight is essential for human health, but overexposure to UV rays can cause serious adverse effects. It is important to detect UV radiation from sunlight in time to prevent damage from excessive exposure. Here, a ready-to-use, easy-to-interpret, inexpensive, reusable, and wearable all-in-one UV monitoring and shielding sensor SP-TPE@PU textile has been developed. The SP-TPE@PU textiles are constructed by photochromic molecule SP-TPE and commercial polymer polyurethane (PU) through electrospinning. The SP-TPE molecule acts as the sensor component, and PU contributes to high flexibility. The SP-TPE@PU textiles show remarkable durability (against repeated twisting, curling, bending deformations, and water immersion) and good permeability, making them durable and breathable wearable materials. When exposed to sunlight, the SP-TPE@PU textiles rapidly exhibit significant color changes due to the efficient isomerization of SP-TPE, serving as an early warning and monitoring of UV radiation. In addition, the SP-TPE@PU textiles can revert to the initial state with visible light irradiation for reuse. Furthermore, the SP-TPE@PU textiles possess excellent UV shielding ability, contributing to human body protection. Simple and easy operation, significant and reversible color changes, good breathability and mechanical properties make SP-TPE@PU textiles reusable and wearable all-in-one UV monitoring and shielding sensors.

Amphiphilic asymmetric brush copolymers (AABCs) possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains. However, the synthesis of AABCs presents challenges, which greatly limits the exploration of their self-assembly behaviors. In this work, we employed dissipative particle dynamics (DPD) simulations to investigate the self-assembly behaviors of AABCs in selective solution. By varying the copolymer concentration and structure, we conducted the self-assembly phase diagrams of AABCs, revealing complex morphologies such as channelized micelles with one or more solvophilic channels. Moreover, the number, surface area, and one-dimensional density distribution of the channelized micelles were calculated to demonstrate the internal structure and morphological transformation during the self-assembly process. Our findings indicate that the morphology of the internal solvophilic channels is greatly influenced by the copolymer structure, concentration, and interaction parameters between the different side chains. The simulation results are consistent with available experimental observations, which can offer theoretical insights into the self-assembly of AABCs.

Conductive polymer composites (CPCs) are widely used in the field of organic electronics as the material basis of high-performance devices, due to their obvious advantages including electrical conductivity, lightness, processability and so on. Research on CPCs has focused on the enhancement of their electrical features and the exploration of their application prospects from conventional fields to heated emerging areas like flexible, stretchable, wearable, biological and biomedical electronics, where their mechanical properties are quite critical to determine their practical device performances. Also, a main challenge to ensure their safety and reliability is on the synergistic enhancement of their electrical behavior and mechanical properties. Herein, we systematically reviews the research progress of CPCs with different conductive fillers (metals and their oxides, carbon-based materials, intrinsically conductive polymers, MXenes, etc.) relying on rich material forms (hydrogel, aerogel, fiber, film, elastomer, etc.) in terms of mechanical property regulation strategies, mainly relying on optimized composite material systems and processing techniques. A summary and prospective overview of current issues and future developments in this field also has been presented.

Recent experimental observations of knotting in DNA and proteins have stimulated the simulation studies of polymer knots. Simulation studies usually identify knots in polymer conformations through the calculation of the Alexander polynomial. However, the Alexander polynomial cannot directly discriminate knot chirality, while knot chirality plays important roles in many physical, chemical, and biological properties. In this work, we discover a new relationship for knot chirality and accordingly, develop a new algorithm to extend the applicability of the Alexander polynomial to the identification of knot chirality. Our algorithm adds an extra step in the ordinary calculation of the Alexander polynomial. This extra step only slightly increases the computational cost. The correctness of our algorithm has been proved mathematically by us. The implication of this algorithm in physical research has been demonstrated by our studies of the tube model for polymer knots. Without this algorithm, we would be unable to obtain the tubes for polymer knots.

Polyimide (PI) is widely used in high-frequency communication technology due to its exceptional comprehensive properties. However, traditional PI has a relatively elevated dielectric constant and dielectric loss. Herein, the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films. In comparison to the dielectric constant of 2.9 of neat PI, PI with an interchain cross-linking structure containing 2 wt% 1,3,5-tris(4-aminophenyl)benzene (TAPB) (interchain-PI-2) exhibited the reduced dielectric constant of 2.55 at 1 MHz. The PI films with intrachain cross-linking structure containing 2 wt% TAPB (intrachain-PI-2) exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of 0.0075 at 1 MHz. It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport. The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced. Moreover, in contrast to interchain-PI films, the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased. This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.

Electrospun nanofibrous separators, despite lacking superior mechanical strength, have gained widespread attention with high porosity and facile processing. Herein, utilizing the fact that thermal imidization temperature of poly(amic acid) (PAA) into polyimide (PI) coincides with the pre-oxidation temperature of polyacrylonitrile (PAN) into carbon fiber, we proposed a new cross-electrospinning strategy to obtain a composite nanofibrous separator (PI/oPAN) randomly interwoven by PI and pre-oxidized PAN (oPAN) nanofibers, via synchronously electrospinning the PAA and PAN onto the same collector and then heat-treating for 2 h at 300 °C. The resultant PI/oPAN separator was able to preserve high porosity (71.7%), electrolyte wettability and thermal stability of PI nanofibrous membrane, and surprisingly exhibited high mechanical strength, being 3 times of PI, which mainly because of the numerous adhesion points generated by the melting of PAN in the pre-oxidation process. Meanwhile, the polar groups of oPAN and 3D fibrous network enhanced the PI/oPAN separator’s ionic conductivity and Li⁺ transference number, rendering the corresponding cell with more stable cycling performance than cells assembled with pure PI, PAN or commercial PP separator. Therefore, this work might provide a new avenue for the ongoing design and further development of LIB separators capable of high safety and high performance.

Metal-backboned polymers with anisotropy microstructures are promising for conductive, optoelectronic, and magnetic functional materials. However, the structure-property relationships governing the interplay between the chemical structure and electromagnetic property of the metal-backboned polymer have been rarely investigated. Here we report a carbon/nickel hybrid from metal-backboned polymer to serve as electromagnetic wave-absorbing materials, which exhibit high microwave absorption capacity and tunable absorption band. The presence of nickel backbones promote the generation of heterogeneous interfaces with carbon during calcination, thereby enhancing the wave-absorbing capacity of the carbon/nickel hybrid. The C/Ni hybrids show a minimal reflection loss of −49.1 dB at 13.04 GHz, and its frequency of the absorption band can be adjusted by controlling the thickness of the absorption layer.

Hydrogen bonds (H-bonds) are the most essential non-covalent interactions in nature, playing a crucial role in stabilizing the secondary structures of proteins. Taking inspiration from nature, researchers have developed several multiple H-bonds crosslinked supramolecular polymer materials through the incorporation of H-bond side-chain units into the polymer chains. N-acryloyl glycinamide (NAGA) is a monomer with dual amides in the side group, which facilitates the formation of multiple dense intermolecular H-bonds within poly(N-acryloyl glycinamide) (PNAGA), thereby exhibiting diverse properties dependent on concentration and meeting various requirements across different applications. Moreover, numerous attempts have been undertaken to synthesize diverse NAGA-derived units through meticulous chemical structure regulation and fabricate corresponding H-bonding crosslinked supramolecular polymer materials. Despite this, the systematic clarification of the impact of chemical structures of side moieties on intermolecular associations and material performances remains lacking. The present review will focus on the design principle for synthesizing NAGA-derived H-bond side-chain units and provide an overview of the recent advancements in multiple H-bonds crosslinked PNAGA-derived supramolecular polymer materials, which can be categorized into three groups based on the chemical structure of H-bonds units: (1) monomers with solely cooperative H-bonds; (2) monomers with synergistic H-bonds and other physical interactions; and (3) diol chain extenders with cooperative H-bonds. The significance of subtle structural variations in these NAGA-derived units, enabling the fabrication of hydrogen-bonded supramolecular polymer materials with significantly diverse performances, will be emphasized. Moreover, the extensive applications of multiple H-bonds crosslinked supramolecular polymer materials will be elucidated.