Chinese Journal of Polymer Science最新文献

This work proposes a bioinspired hierarchical actuation strategy based on liquid crystal elastomers (LCEs), inspired by the helical topological dynamic adaptation mechanism of plant tendrils, to overcome the bottleneck of precise anisotropic control in LCEs. Mechanically pre-programmed hierarchical LCE structures responsive to near-infrared (NIR) light were fabricated: the oriented constrained actuator achieves asymmetric contraction under NIR irradiation, enabling reversible switching between helix and planar morphologies with multi-terrain grasping capability; the biomimetic vine-like helical actuator, composed of Ag nanowire photothermal layers combined with helical LCE, utilizes temperature-gradient-induced phase transition wave propagation to achieve NIR-controlled climbing motion; the Möbius topology actuator realizes reversible deformation or self-locking states by tuning the twist angle (180°/360°); based on these, a bioinspired koala-like concentric soft robot was constructed, successfully demonstrating tree trunk climbing. This study reveals that artificial helical stretching significantly enhances the molecular chain orientation of LCEs (surpassing uniaxial stretching), reaching up to 1000% pre-strain, and the AgNWs/LCE/PI (Polyimide) tri-layer structure achieves efficient photothermal-mechanical energy conversion via localized surface plasmon resonance (LSPR). This study provides a new paradigm for soft robotics material design and topological programming, demonstrating the potential for remote operation and adaptive grasping.

Ultrasound (US), as an efficient and non-invasive trigger, has been extensively explored in drug delivery and has many advantages, such as deep penetration, low invasiveness, and high biochemical precision. These advantages demonstrate the immense clinical potential of ultrasound. This study aimed to provide a comprehensive analysis of ultrasound-induced shear forces that exhibit covalent/non-covalent bond cleavage and reactive oxygen species (ROS)-mediated remote control of nanocarriers. By doing so, we can gain a deeper understanding of the vital role, significant advantages, and untapped potential of ultrasound in molecular-level drug activation. Furthermore, clinical translation faces challenges such as the low drug-loading capacity of polymer chains, frequency compatibility between ultrasound parameters and biological systems, insufficient ROS generation, and biocompatibility of current sonosensitizers. To solve these problems, ultrasound mechanochemistry has emerged as a versatile therapeutic modality to promote the development of medical treatments.

To address the poor mechanical properties of polydimethylsiloxane (PDMS) and enhance the understanding of the reinforcement mechanisms of aerogel network structures in rubber matrices, this study reinforced PDMS using an ordered interconnected three-dimensional montmorillonite (MMT) aerogel network. The average pore diameter of the aerogels was successfully reduced from 11.53 µm to 2.51 µm by adjusting the ratio of poly(vinyl alcohol) (PVA) to MMT via directional freezing. Changes in the aerogel network were observed in field emission scanning electron microscope (FESEM) images. After vacuum impregnation, the aerogel network structure of the composites was observed using FESEM. Tensile tests indicated that as the pore diameter decreased, the elongation at break of the composites first increased to a peak of 329.61% before decreasing, while the tensile strength and Young’s modulus continuously increased to their maximum values of 6.29 MPa and 24.67 MPa, respectively. Meanwhile, FESEM images of the tensile cracks and fracture surfaces showed that with a reduction in aerogel pore diameter, the degrees of crack deflection and interfacial debonding increased, presenting a rougher fracture surface. These phenomena enable the composites to dissipate substantial energy during tension, thus effectively improving the mechanical strength of the composites. The present work elucidates the bearing of ordered three-dimensional aerogel network structures on the performance of rubber matrices and provides crucial theoretical insights and technical guidance for the creation and optimization of high-performance PDMS-based composites.

Understanding the thermodynamic behavior of complex fluids in confined environments is critical for various industrial and natural processes including but not limited to polymer flooding enhanced oil recovery (EOR). In this work, we develop Atif-V2.0, an extended classical density functional theory (cDFT) framework that integrates the interfacial statistical associating fluid theory (iSAFT) to model multicomponent associating fluids composed of water-soluble polymers, alkanes, and water. Building on the original theoretical framework of Atif for modeling nanoconfined inhomogeneous fluids, Atif-V2.0 embeds explicit solvent and captures additional physical interactions - hydrogen bonding, which are critical in associating fluid systems. The other key feature of Atif-V2.0 is its ability to account for polymer topology. We demonstrate its capability by predicting the equilibrium structure and thermodynamic behavior of branched hydrolyzed polyacrylamide solutions near hard walls with various branching topologies, which provides a robust theoretical tool for the rational design of EOR polymers.

Poly(vinylidene fluoride) (PVDF) foam has received widespread attention due to its high strength, and excellent combination of flame-retardancy, antibacterial performance, and chemical stability. However, the foaming ability of conventional PVDF is severely limited by its rapid crystallization kinetics and poor melt strength. Although ultra-high molecular weight PVDF (H-PVDF) theoretically offers prolonged melt elasticity favorable for foaming, the extremely high melt viscosity poses substantial processing challenges, and its foaming behavior has remained largely unexplored. To address these issues, this study proposes a novel fabrication strategy combining solvent casting with microcellular foaming to prepare H-PVDF foams. Dynamic mechanical analysis and differential scanning calorimetry reveal that extensive chain entanglements in H-PVDF impose constraints on crystallization and significantly enhance melt strength. By tuning the processing parameters, the distinctive foaming behavior of H-PVDF under various conditions is systematically elucidated. Remarkably, a record-high expansion ratio of 55.6-fold is achieved, accompanied by a highly uniform and fine cellular structure. The resulting H-PVDF foams exhibit a low thermal conductivity of 31.8 mW·m^–1·K^–1, while retaining excellent compressive strength, flame-retardancy, and hydrophobicity. These outstanding properties highlight the great potential of H-PVDF foams as the thermal insulation materials for applications in aerospace, energy infrastructure, and other extreme environments.

Dielectric films are critical components in the fabrication of capacitors. However, their reliance on petroleum-derived polymers presents significant environmental challenges. To address this issue, we report on a high-performance biomass-based dielectric material derived from vanillin (VA), a renewable aromatic aldehyde. Vanillin was first esterified to synthesize vanillin methacrylate (VMA), which was then copolymerized with methyl methacrylate (MMA) via free-radical polymerization to yield P(VMA-MMA). By crosslinking the aldehyde groups in VMA with the amine groups in the polyether amine D400 (PEA), we fabricated a series of P(VMA-MMA)@PEA dielectric films with precisely tunable crosslinking densities. The unique molecular structure of vanillin, featuring both a benzene ring and an ester group, facilitates strong δ-π interactions and dipolar polarization, synergistically enhancing energy storage density while minimizing dielectric loss. At an optimal P(VMA-MMA) ratio of 1:10 and 80% theoretical crosslinking degree, the dielectric constant reaches 3.4 at 10³ Hz, while the breakdown strength reaches 670.2 MV/m. Furthermore, the film exhibits an energy storage density of 7.1 J/cm³ at 500 MV/m while maintaining a charge-discharge efficiency exceeding 90%. This study demonstrates a green and reliable strategy for designing biomass-based dielectric materials and opens new avenues for the development of eco-friendly energy-storage technologies.

Knotting occurs in polymers and affects polymer properties. Physical understanding of polymer knots is limited due to the complex conformational space of knotted structures. The knotting problem can be handled by the tube model, which assumes that knotted polymer segments are confined in a virtual tube. Recently, we quantified this virtual tube using a computational algorithm. The algorithm was limited to the simplest knot: 3₁ knot. It remains unclear how the tube model and computational algorithm are applied to more complex knots. In this work, we apply the tube model to 4₁, 5₁, and 5₂ knots, resulting in several findings. First, the computational algorithm developed for 3₁ knot cannot be directly applied to 4₁ knot. After modifying the algorithm, we quantify the tubes for 4₁ knot. Second, we find that, for all four knot types, the knotcore region have less average bending energy density than unknotted regions when the chain bending stiffness is small. This counterintuitive result is explained by the tube model. Third, for all four knot types, polymer segments at the boundaries of knot cores adopt nearly straight conformations (almost zero bending) and exhibit lower local bending compared to other knot-core regions and unknotting regions. This local behavior is also consistent with prediction from the tube model. This counterintuitive result is also explained by the tube model. Fourth, for all four knot types, when a polymer has non-uniform bending stiffness, a knot prefers certain chain positions such that the knot boundary locates at one stiff segment. Overall, our work paves the way for applying the tube model to complex polymer knots and obtains many common results for different knot types, which can be useful in understanding many knotting systems, such as DNA knots in vivo.

As a naturally occurring terpenoid that is abundant in essential oils, citronellal remains largely unexplored in polymer science. Herein, we present a novel strategy for converting bio-based citronellal into the diene monomer 6,10-dimethyl-1,3,9-undecatriene (DMUT), which undergoes neodymium-catalyzed coordination polymerization to yield poly(6,10-dimethyl-1,3,9-undecatriene) (PDMUT), a bio-derived polydiene polymer. This provides a facile and sustainable route for transforming renewable citronellal into functional polymers. The effects of polymerization conditions on the catalytic performance and polymer characteristics, including molecular weight, polydispersity, and microstructure, were systematically investigated. In addition, DMUT was successfully copolymerized with isoprene (IP) and 1,3-butadiene (BD), yielding copolymers with tunable compositions and microstructures. These results demonstrate the versatility of DMUT as a renewable building block for both homopolymers and copolymers, paving the way toward bio-based elastomeric materials with customizable properties.

Eutectogels are considered to have immense application potential in the field of flexible wearable ionotronic devices because of their excellent ionic conductivity, thermal and electrochemical stability, and non-volatility. However, most existing technologies still struggle to achieve synergistic optimization of key performance indicators, such as high mechanical strength and ionic conductivity. To address this challenge, this study successfully prepared a green eutectogel material with outstanding comprehensive properties by leveraging the high solubility of glycerol in a polymerizable deep eutectic solvent (DES) composed of acrylic acid and choline chloride. The resulting eutectogels exhibited a high transparency (89%), high mechanical strength (up to 2.8 MPa), and exceptional tensile performance (up to 1385%). The fabricated flexible sensor demonstrated ideal linear sensitivity (gauge factor: 0.88), a broad response range (1%–100%), and reliable stability (over 1000 cycles), enabling the precise monitoring of human motion (e.g., finger bending and wrist rotation). The flexible strain sensor based on this eutectogel is expected to show promising prospects for medical monitoring, human-machine interaction, and industrial sensing applications.