- Abstract：Natural rubber (NR) is a crucial elastic material used for damping and sealing applications in the nuclear industry, but its mechanical stability under radiation remains inadequate. Current efforts to improve radiation resistance rely on the addition of antiradiation agents, however, the effects of the components and microstructures of NR itself on radiation resistance remain unclear. In this study, we compared the composition and structure differences of four typical commercially used NR materials and investigated their effects on gamma radiation resistance. Furthermore, we examined the impact of non-rubber components (NRC) in NR on radiation resistance using deproteinized and dephosphorylated NR model samples. Our results revealed that NRC, such as proteins and phospholipids can enhance the strength of natural rubber before radiation exposure. However, after the removal of NRC, the samples exhibited improved mechanical stability under irradiation. Additionally, the ash content in NR could also influence the radiation resistance, as metal ions may react with the active centers produced by radiation, thereby enhancing the radiation resistance of the rubber. This work identifies the effect of non-rubber components in NR on radiation resistance and may serve as a reference for screening and developing radiation-resistant NR materials.Keywords：Natural rubber;Non-rubber components2|0|0
Updated：2025-04-24 - Abstract：Enhancing the lubricating properties and antibacterial adhesion resistance of implantable medical materials is critical to prevent soft tissue injury during implantation and the formation of bacterial biofilms. Prior studies may have exhibited limitations in the preparation methodologies and long-term stability of coatings for implantable medical materials. In this study, we developed a multilayered hybrid hydrogel coating method based on the rate difference of polymerization initiation on the material surface. The acquired coating with persistent lubrication capability retained its functionality after 2×104 cycles of friction and 21 days of PBS immersion. A quaternary ammonium salt coating with antibacterial properties was introduced to further functionalize the coating. Animal experiments demonstrated that this coating exhibited remarkable effects on delaying encrustation and bacterial colonization. These studies indicate that this simple method of introducing lubricating and antibacterial coatings on catheters is likely to enhance the biocompatibility of medical devices and has broad application prospects in this field of medical devices.Keywords：Hierarchical structure;Surface modification2|0|0Updated：2025-04-24
- Abstract：Controllably tuning the sensing performance of flexible mechanical sensors is important for them to realize on-demand sensing of various mechanical stimuli in different application scenarios. However, current regulating strategies focus on the construction process of individual sensors, the response performance of the as-formed sensors is still hard to autonomously tune with external stimulus changes like human skin. Here, we propose a new strategy that realizes post-tuning of the sensing performance by introducing a temperature-dependent phase transition elastomer into the sensing film. Through an interfacially confined photopolymerization reaction, a graphene-based phase-transition elastomeric (GPTE) film with a robust interface and excellent conductivity is well-formed at the water/air interface. Benefiting from the crystallization-melt dynamic switching in the elastomer network, the GPTE film could experience the reversible transformation between soft (1.65 MPa) and stiff (12.27 MPa) states, showing huge changes of elastic modulus up to seven times near the phase transition temperature (28.5 °C). Furthermore, the GPTE film is designed into a suspended perceptual configuration realizing the dynamic detection of 3D deformation adapted to temperature changes with up to 3.5-fold difference in response sensitivity. Finally, the self-adaptive sensing behavior of temperature-mediated 3D deformation is demonstrated by the effective detection of the dynamic stimulation process of cold and hot water droplets by the GPTE suspended film. The proposed strategy of phase transition-induced post-tuning of sensing performance could greatly facilitate flexible mechanical sensors towards a more intelligent one.Keywords：Phase transition elastomer;Crystallization-melt switching;Tunable modulus;Suspended sensor;Tunable sensing performance98|37|0Updated：2025-03-17
- Abstract：The diversity, complexity, heterogeneity, and drug resistance of tumors make it challenging to meet the clinical needs of a single apoptosis-inducing chemotherapy. The combination of apoptosis and ferroptosis is expected to address the side effects of chemotherapy and enhance therapeutic efficacy. Here, an amphiphilic pH-responsive doxorubicin (DOX) and ferrocene (Fc)-containing copolyprodrug (P(ADH-DOX-Fc)-PEG) was designed with high DOX and Fc content of 66.5% and 0.58 mmol/g by a facile polycondensation for combining chemotherapy with ferroptosis in cancer treatment. A drug self-delivery system (DSDS) with an average hydrodynamic diameter (Dh) of 135 nm can be easily obtained via self-assembly with the polyprodrug blocks as the hydrophobic core and PEG as the hydrophilic brush. The cumulative DOX release reached 72.7% in the simulated tumor intracellular acidic microenvironment within 56 h, whereas the premature drug leakage was only 6.2% in the simulated normal physiological medium. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results indicated an IC50 of 8.2 μg/mL, exhibiting enhanced anti-tumor efficacy and a successful combination of apoptosis and ferroptosis, with a combination index (CI) of 0.88.Keywords：Combination therapy of apoptosis and ferroptosis;Drug self-delivery system;Copolyprodrug;Doxorubicin;Ferrocene57|19|0Updated：2025-03-13
- Abstract：Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria. However, the specific contributions of different functional residues remain unclear. Herein, we introduce an approach to deconstruct and mimic these residues using synthetic homopolymers and random copolymers with phenyl, amino, carboxyl, and hydroxyl functional groups using reversible addition-fragmentation chain transfer (RAFT) polymerization. The resulting polymers, designed with comparable molecular weights (Mn: 10–20 kDa) and narrow dispersities (PDI<1.3), mimic the diverse surface chemistry of amyloid-like proteins, enabling systematic investigation of their adhesive properties. The interfacial adhesion forces of different polymer films were quantified using atomic force microscopy (AFM) with a colloidal probe. Remarkably, copolymers with multiple functional groups demonstrated significantly enhanced adhesion compared to homopolymers, a trend corroborated by macroscopic shear strength and stability tests. These results highlight that the synergistic effects of multiple functional groups are crucial for achieving universal interfacial adhesion of macromolecules, offering insights into protein adhesion mechanisms, and guiding polymer-based interfacial modifications.Keywords：Protein-mimetic polymers;Amyloid;Adhesion mechanism;Surface functional group;Synergistic effect31|28|0Updated：2025-03-13
- Abstract：Herein, a simple method for preparing poly(vinylidene fluoride) (PVDF) films with controlled β/γ ratios by spin-coating assisted by potassium bromide (KBr) is proposed. The results show that the relative fraction of the β phase (denoted as Fβ) for the films prepared on the KBr surface first decreased until a critical temperature (denoted as Tc) was reached, and then increased with increasing spin-coating temperature. This was related to the dissolved K and Br ions in the films. Further experiments showed that below Tc, high humidity can enhance Fβ but exhibit an adverse effect at and above Tc. The high content of K and Br ions in the PVDF/KBr blend film and larger shear stress can facilitate the formation of the β phase, leading exclusively to the formation of β- and γ-phases. The mechanism responsible for the change in Fβ with temperature was proposed: below Tc, the decrease in water intake with increasing temperature results in the decline of Fβ, whereas above Tc, the increase in Fβ with temperature is attributed to the synergistic effect of ions and shear stress. Ultimately, this paves the way for fabricating PVDF films with tailored β/γ ratios for electroactive and energy-harvesting applications.Keywords：Poly(vinylidene fluoride);KBr;Spin coating;Polymorph46|14|0Updated：2025-03-13
- Abstract：The recovery of ionic liquids (ILs) has attracted growing attention as an indispensable process in “green” industrial applications. Forward osmosis (FO) has proven to be a sustainable method for concentrating the very dilute aqueous solutions of ILs at ambient temperature, in which semi-permeable membranes play a vital role in determining the recovery efficiency. Herein, we use interfacial polymerization method to prepare thin-film composite membranes consisting of polyamide skin layer and electrospun nanofibrous substrate with tunable water permeability and IL selectivity for osmotic enrichment of imidazolium ILs from their dilute aqueous solutions through FO process. The resulting FO membrane shows a compact polyamide layer with a thickness of 30–200 nm, guranteeing a high selectivity to ILs and water. Meanwhile, the nanofibrous substrate with large and interconnect pores as well as low tortuosity, providing mechanical and permeable support for the composite membranes. IL structure influences the osmotic pressure difference as well as the interactions with polyamide layer of the membrane and thus determines the whole concentration process. First, the alkyl chain growth augments the osmosis pressure difference between the ILs solution and draw solution, resulting in an enhancement in driving force of water osmosis and IL enrichment. Moreover, alkyl length aggravates external concentration polarization caused by the enhanced adsorption of ILs onto the skin layer via electrostatic and alkyl-π interactions. Meanwhile, such adsorbed ILs further enhance the IL retention but decrease the reverse salt diffusion. Therefore, imidazolium ILs with varied alkyl lengths are ultimately enriched with a 100-fold increase in concentration from their dilute aqueous solutions with high IL/NaCl rejection and low IL loss. Remarkably, the final concentration of IL with longest alkyl length reaches the highest (6.4 mol·L–1). This work provides the insights in respect to material preparation and process amelioration for IL recovery with high scalability at mild conditions.Keywords：Thin-film composite membrane;Forward osmosis;Ionic liquids;Interfacial polymerization;Electrospun nanofiber20|17|0Updated：2025-03-13
- Abstract：Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution. We found that both the mean-square displacement
$ {g}_{3} \left(t\right) $ $ {c}_{{\mathrm{s}}} $ $ D $ $ A $ $ A $ $ A $ $ D $ $ A $ $ {g}_{3} \left(t\right) $ $ A $ Keywords：Molecular dynamics simulation;Sliding dynamics;Diblock polyelectrolyte20|38|0Updated：2025-03-11 - Abstract：The development of degradable and chemically recyclable polymers is a promising strategy to address pressing environmental and resource-related challenges. Despite significant progress, there is a need for continuous development of such recyclable polymers. Herein, PPDO-PLLA-PU copolymers were synthesized from poly(p-dioxanone)-diol (PPDO-diol) and poly(L-lactide)-diol (PLLA-diol) by chain extension reaction. The chemical structures and microphase structures of PPDO-PLLA-PU were characterized, and their crystalline properties, mechanical properties, and degradation behaviors were further investigated. Significantly, the distribution of PLLA phase in the copolymer matrix showed a rod-like microstructure with a slight orientation, despite the thermodynamic incompatibility of PPDO and PLLA segments. Moreover, on the basis of this microphase separation, PPDO spherulites can crystallize using the interface of the two phases as nucleation sites. Accordingly, the combined effect of above two contributes to the enhanced mechanical properties. In addition, PPDO-PLLA-PU copolymers have good processability and recyclability, making them valuable for a wide range of applications.Keywords：Recyclable;Degradable;Poly(p-dioxanone);Microphase separation54|19|0Updated：2025-02-13
- Abstract：Polymer adsorption at solid interfaces plays an important role in the dynamics of nanoscale polymer films. We investigated the influence of the interfacial chain adsorption on the glass transition temperature (Tg) and dewetting of polystyrene (PS) thin films on a graphene substrate that has strong interaction with PS. We found that the Tgs of PS films show a non-monotonic trend with increasing amount of polymer adsorption at the interface—first increasing and then decreasing, and this change in Tg is accompanied by a wetting-dewetting transition of the PS films. Film morphological analysis showed that the PS films dewet from the interfacially adsorbed layers rather than from the substrate, i.e., autophobic dewetting, indicating the presence of an unfavorable interaction between the adsorbed and free PS chains. We ascribed the repulsive interaction to the formation of a dense adsorbed layer on graphene due to the π-π interaction between PS and graphene, which prevents the non-adsorbed PS chain from penetrating into the adsorbed layer. This may lead to drops in Tg at high adsorption extent.Keywords：Polymer adsorption;Interfacial dynamics;Graphene;Autophobic dewetting;Thin films125|105|0Updated：2024-11-14
- Abstract：Chemical recycling/upcycling of plastics has emerged as one of the most promising strategies for the plastic circular economy, enabling the depolymerization and functionalization of plastics into valuable monomers and chemicals. However, studies on the depolymerization and functionalization of challenging super engineering plastics have remained in early stage and underexplored. In this review, we would like to discuss the representative accomplishments and mechanism insights on chemical protocols achieved in depolymerization of super engineering plastics, especially for poly(phenylene sulfide) (PPS), poly(aryl ether)s including poly(ether ether ketone) (PEEK), polysulfone (PSU), polyphenylsulfone (PPSU) and polyethersulfone (PES). We anticipate that this review will provide an overall perspective on the current status and future trends of this emerging field.Keywords：Super engineering plastics;Chemical recycling/upcycling;Depolymerization;Functionalization148|140|0Updated：2024-11-08
- Abstract：As a powerful synthetic tool, ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) has been widely utilized to prepare diverse heteroatom-containing polymers. In this contribution, we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP. Because of the efficient hydrolysis reactions of the imine group, the generated copolymer can be easily degraded under mild condition. Moreover, the generated degradable product was the telechelic polymer bearing amine group, which was highly challenged for its direct synthesis. And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation. The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.Keywords：Degradable polymer;Ring-opening metathesis polymerization;Imine-based polymer;Copolymerization109|100|0Updated：2024-11-07
- Abstract：Designing the kinetic pathways of assembling macromolecules such as block copolymers and DNA strands is crucial not only for an achievement of thermodynamically equilibrium nanostructures over macroscopic areas, but also for a better understanding of formation process of higher-level superstructures where well-tailored assemblies act as mesoscopic building units. Theoretical analysis and computer simulations provide excellent opportunities to microscopically reveal the kinetics and mechanism of structural evolution as well as the collective behaviors of building units. In this perspective, we summarize our efforts of theoretical and computational modelling to understand the long-range ordering mechanisms and the organization kinetics of assembling macromolecules along designable pathways. First, we present the computational modelling and recent strategies of designable pathways for the achievement of long-range ordering. Then, from the computational views, we give the applications of pathway-designed strategies to explore the ordering mechanism and kinetics in the course of structural evolution, covering the block copolymers and their nanocomposites under zone annealing as well as the hierarchical self-assembly of mesoscopic building units (e.g., patchy micelles and DNA-functionalized nanoparticles). Finally, we outlook future directions in the field of designable pathways for the achievement of long-range ordered nanostructures. This perspective could promote further efforts towards the wide applications of theoretical and computational modelling in the construction of soft hybrid metamaterials.Keywords：Dynamic self-consistent field theory;Structural evolution;Block copolymers;Hierarchical self-assembly;Polymerization62|72|0Updated：2023-03-03
- Abstract：The integration of high mechanical toughness, impact strength as well as excellent flame-retardant properties toward epoxy resins (EPs) have always been a dilemma. The inadequate overall performance of EPs severely restricts their sustainable utilization in engineering aspects over long-term. Herein, a new bio-based agent (diglycidyl ether of magnolol phosphine oxide, referred as DGEMP) derived from magnolol (classified as lignan), extracted from natural plants Magnolia officinalis, was successfully synthesized and further employed as a flame-retardant reactive additive to diglycidyl ether of bisphenol A (DGEBA). As demonstration, the composite resin, DGEBA/15DGEMP (15 wt% DGEMP), achieved an Underwriters Laboratories-94 V-0 rating with a high limiting oxygen index (LOI) value (41.5%). In cone calorimeter tests, it showed that heat release and smoke production were effectively inhibited during combustion, wherein the peak heat release rate (PHRR) value of DGEBA/15DGEMP was reduced by 50% compared to neat DGEBA. Additionally, it exhibited a superior tensile strength (82.8 MPa), toughness (5.11 MJ/m3) and impact strength (36.5 kJ/m2), much higher than that of neat DGEBA (49.7 MPa, 2.05 MJ/m3 and 20.9 kJ/m2). Thus, it is highly anticipated that DGEMP imparts significantly improved mechanical and fire-retarded properties to conventional EPs, which holds a great potential to address the pressing challenges in EP thermosets industry.Keywords：Epoxy resin;Magnolol;Phosphine oxide;Toughness;Flame retardant340|80|2Updated：2023-02-21
- Abstract：Dissipative particle dynamics (DPD) with bond uncrossability shows a great potential in studying entangled polymers, however relatively little is known of applicability range of entangled DPD model to be use as a model for ideal chains and properly describe the full dynamics of entangled melts. Therefore, we perform a comprehensive study on structure, dynamics and linear viscoelasticity of a typical DPD entangled model system, semiflexible linear polymer melt. These polymers obey Flory’s ideality hypothesis in chain dimensions, but their local structure exhibits nonideal behavior due to weak correlated hole effect. Both monomer motion and viscoelasticity relaxation reproduce the full pictures as predicted by reptation theory. The stronger chain length dependent diffusion coefficient and relaxation time as well as dynamic moduli are in close agreement with predictions of modern tube model that accounts for additional relaxation mechanisms besides chain reptation. However, an anomalous sub-diffusive center of mass motion is observed both before and after the intermediate reptation regime and the cross-correlation between chains is not negligible even these polymers obey stress-optical law, indicating limitations of the reptation theory. Hence semiflexible linear entangled DPD model can correctly describe statics and dynamics of entangled polymer melts.Keywords：Entangled polymer melts;Dynamics;Linear viscoelasticity;Dissipative particle dynamics51|72|1Updated：2023-02-07
- Abstract：A deep neural network model generally consists of different modules that play essential roles in performing a task. The optimal design of a module for use in modeling a physical problem is directly related to the success of the model. In this work, the effectiveness of a number of special modules, the self-attention mechanism for recognizing the importance of molecular sequence information in a polymer, as well as the big-stride representation and conditional random field for enhancing the network ability to produce desired local configurations, is numerically studied. Network models containing these modules are trained by using the well documented data of the native structures of the HP model and assessed according to their capability in making structural predictions of unseen data. The specific network design of self-attention mechanism adopted here is modified from a similar idea in natural language recognition. The big-stride representation module introduced in this work is shown to drastically improve network's capability to model polymer segments of strong lattice position correlations.Keywords：Deep neural network;Self-attention mechanism;Big-stride representation;Conditional random methods8|44|1Updated：2023-01-31
- Abstract：Entropic elasticity of single chains underlies many fundamental aspects of mechanical properties of polymers, such as high elasticity of polymer networks and viscoelasticity of polymer liquids. On the other hand, single chain elasticity is further rooted in chain connectivity. Recently, mechanically interlocked polymers, including polycatenanes and polyrotaxanes, which are formed by connecting their building blocks (cyclic and linear chains) through topological bonds (e.g., entanglements), emerge as a conceptually new kind of polymers. In this work, we employ computer simulations to study linear elasticity of single linear polycatenane (or [n]catenane), in which n rings are interlocked through catenation into a chain of linear architecture. Aim of this work is to illuminate the specific role of catenation topology in the elastic moduli of linear polycatenanes by comparing with those of their [n]bonded-ring counterparts, which are formed by connecting the same number of rings but via covalent bonds. Simulation results lead to a conclusion that topological catenation makes [n]catenanes exhibit larger elastic moduli than their linear and [n]bonded-ring counterparts,i.e., larger elastic moduli in the case of [n]catenanes. Furthermore, it is revealed that those [n]catenanes composed of a smaller number of rings (smaller n) possesses larger elastic moduli than others of the same total chain lengths. Molecular mechanisms of these findings are discussed based on conformational entropy due to topological constraints.Keywords：Single chain elasticity;Polycatenane;Computer simulation27|64|0Updated：2023-01-31
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