- Abstract：Soft robots have shown great advantages with simple structure, high degree of freedom, continuous deformation, and benign human-machine interaction. In the past decades, a variety of soft robots, including crawling, jumping, swimming, and climbing robots, have been developed inspired by living creatures. However, most of the reported bionic soft robots have only a single mode of motion, which limits their practical application. Herein, we report a fully 3D printed crawling and flipping soft robot using liquid metal incorporated liquid crystal elastomer (LM-LCE) composite as the actuator. With the application of voltage, liquid metal works as the conductive Joule heating material to induce the contraction of the LCE layer. The bending angle of the LM-LCE composite actuator highly depends on the applied voltage. We further demonstrate that the soft robot can exhibit distinct moving behaviors, such as crawling or flipping, by applying different voltages. The fully 3D printed LM-LCE composite structure provides a strategy for the fast construction of soft robots with diverse motion modes.Keywords：Liquid crystal elastomer;Liquid metal;Soft actuator;3D printing49|27|0
Updated：2025-03-19 - 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 performance36|25|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;Ferrocene28|12|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 effect17|23|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;Polymorph32|10|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 nanofiber12|7|0Updated：2025-03-13
- Abstract：High catalytic efficiencies in ring opening polymerization (ROP) of a large ring-sized macrolactone, ω-pentadecalactone (PDL), by using transition metal Fe(II)-based catalysts were achieved for the first time in this study. Benefited from the bulky nature of the ligated α-diimine ligands, as evidenced from single-crystal structures, as well as the weakly oxophilic nature of the metal centers, chain transesterification reactions could be partially suppressed, allowing the polymerization proceed in a living-like and semi-controllable manner, i.e. good linear dependence of propagation rates on catalyst concentration and PDL concentration as observed in the detailed kinetics studies. The whole polymerization proceeds via a “coordination-insertion” mechanism, and with the aid of density functional theory (DFT) calculation studies, a “slow insertion → fast elimination” manner was demonstrated for the monomer propagation step, suggesting the insertion of Fe-OR into the carbonyl group C＝O as the rate-determining step. The present catalytic system also showed fast chain transfer reactions to alcohol compounds, affording quasi-immortal characteristics. DFT calculations showed that such a transfer reaction only required an energy barrier of 6.4 kcal/mol, performing a good consistency with the fast chain transfer rates.Keywords：ω-Pentadecalactone;Ring opening polymerization;Polyester;Ferrous catalysts15|3|0Updated：2025-03-13
-
Mesoscopic Simulation on Self-assembly of Diphenylalanine-based Analogue with Ethylenediamine Linker
Abstract：Diphenylalanine and its analogs cause many concerns owing to their perfect self-assembly properties in the fields of biology, medicine, and nanotechnology. Experimental research has shown that diphenylalanine-based analogs with ethylenediamine linkers (PA, P = phenylalanine, and A = analog) can self-assemble into spherical assemblies, which can serve as novel anticancer drug carriers. In this work, to understand the assembly pathways, drug loading behavior, and formation mechanism of PA aggregates at the molecular level, we carried out dissipative particle dynamics (DPD) simulations of PA molecule systems. Our simulation results demonstrate that PA molecules spontaneously assemble into nanospheres and can self-assemble into drug-loaded nanospheres upon addition of the cancer chemotherapeutic agent doxorubicin (DOX). We also found that the hydrophobic side chain beads of PA molecules exhibited a unique onion-like distribution inside the nanospheres, which was not observed in the experiment. The onion-like nanospheres were verified by calculating the radial distribution function (RDF) of the DPD beads. Furthermore, based on the analysis of the percentages of different interaction components in the total nonbonded energies, main chain-side chain interactions between PA molecules may be important in the formation of onion-like nanospheres, and the synergistic effects of main chain-side chain, main chain-drug, side chain-drug, and main chain-solvent interactions are significant in the formation of drug-loaded nanospheres. These findings provide new insights into the structure and self-assembly pathway of PA assemblies, which may be helpful for the design of efficient and effective drug delivery systems.Keywords：Diphenylalanine-based analogue;Self-assembly;Drug delivery31|30|0Updated：2025-03-11 - 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 polyelectrolyte16|23|0Updated：2025-03-11 - Abstract：Autonomous, adaptable, and multimodal locomotion capabilities, which are crucial for the advanced intelligence of biological systems. A prominent focus of investigations in the domain of bionic soft robotics pertains to the emulation of autonomous motion, as observed in natural organisms. This research endeavor faces the challenge of enabling spontaneous and sustained motion in soft robots without relying on external stimuli. Considerable progress has been made in the development of autonomous bionic soft robots that utilize smart polymer materials, particularly in the realms of material design, microfabrication technology, and operational mechanisms. Nonetheless, there remains a conspicuous deficiency in the literature concerning a thorough review of this subject matter. This study aims to provide a comprehensive review of autonomous soft robots that have been developed based on self-regulation strategies that encompass self-propulsion, self-oscillation, multi-stimulus response, and topological constraint structures. Furthermore, this review engages in an in-depth discussion regarding their tunable self-sustaining motion and recovery capabilities, while also contemplating the future development of autonomous soft robotic systems and their potential applications in fields such as biomechanics.Keywords：Smart materials;Autonomous soft robots;Self-regulation;Self-oscillation;Smart structure68|82|0Updated：2025-02-27
- Abstract：With the rise in environmental awareness, the development of smart polymer materials is gradually becoming environmentally friendly and sustainable. Fluorescent liquid crystal elastomers (LCE) can change their shape or optical properties in response to external stimuli, showing great potential for applications in sensing, information storage, and encryption. However, their life cycle is often unsustainable and not in line with the circular economy model. Based on the principle of green chemistry, a fluorescent LCE was developed through the co-polymerization of multiple monomers with 1,2-dithiolane end groups, which exhibited excellent self-healing, reprocessing, and closed-loop recyclability. In addition, by tailoring the phase transition temperature of the LCE, the transparency and fluorescence intensity of the resulting material can change at a low temperature of 8.0 °C. By further integrating light or acid/base-triggered fluorescence information, a proof-of-concept for temperature monitoring during short-time vaccine transportation using the reusable fluorescent LCE film is demonstrated. This study establishes a new environmentally friendly manufacturing strategy for multifunctional LCE materials.Keywords：Liquid crystal elastomer;1;2-Dithiolane;Reversible ring-opening polymerization;Temperature monitor;Renewable30|53|0Updated：2025-02-27
- Abstract：The strain-induced crystallization behaviors of ultrasonic micro-injection molded poly(L-lactic acid)/poly(D-lactic acid) (PLLA/PDLA) samples from an amorphous state were investigated by stress-strain relations and in situ wide angle X-ray diffraction (WAXD) measurements. The formation of direct strain-induced stereocomplex (SC) was evident. In samples molded at 50 and 80 °C, this phenomenon can be attributed to the acceleration of the ordered structures due to the existence of a large number of SC nuclei. The SC nuclei are assumed to serve as the transient physical cross-links to initiate the strain-induced crystallization. The onset of strain-induced crystallization is analogous to the heating induced structural reorganization. Consequently, the observed strain-induced SC process can be considered a pseudo process, which is actually thermally induced. Upon further stretching, the actual strain-induced crystallization occurs with the exclusive formation of the homocrystallite (HC), while the preceding formed SC crystals undergo slight fragmentation during subsequent tensile deformation. At 120 °C, due to the reduced number of SC nuclei within the sample, the occurrence of cold crystallization during stretching plays a more significant role than SC nuclei with respect to the strain-induced SC process, as demonstrated by in situ WAXD measurements upon annealing in both the static and stretched states.Keywords：Amorphous PLLA/PDLA blend;Strain-induced crystallization;Strain-induced SC formation72|54|0Updated：2025-02-21
- Abstract：Polyaniline (PANi) hydrogels have a wide range of applications in artificial skin, flexible robotics, and movement monitoring. Nevertheless, limited by the modulus mismatch between rigid PANi and the soft hydrogel matrix, the high strength and toughness of the PANi hydrogel are mutually exclusive. Although the introduction of sacrificial bonds into the hydrogel network can alleviate this contradiction to a certain extent, it always causes pronounced energy hysteresis during hydrogel deformation. Inspired by the energy storage and release of macroscopic springs, in this work, we propose a molecular entanglement approach for the fabrication of PANi hydrogels featuring high toughness and low hysteresis, where flexible poly(ethylene glycol) (PEG) is entangled with chemically cross-linked poly(acrylic acid) (PAA) as a hydrogel matrix, and rigid PANi as a conductive filler. The resultant PAA/PEG/PANi hydrogel exhibited high mechanical properties (fracture strength of 0.75 MPa and toughness of 4.81 MJ·m−3) and a low energy dissipation ratio (28.2% when stretching to 300%). Moreover, the PAA/PEG/PANi hydrogel possesses a good electrical response to external forces and can be employed as a strain sensor to monitor human joint movements by producing specific electrical signals. This work provides a straightforward strategy for preparing tough conductive PANi hydrogels with low hysteresis, showing potential for the development of healthcare devices.Keywords：Polyaniline hydrogel;Low hysteresis;High toughness;Physical entanglement27|27|0Updated：2025-02-13
- 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 separation32|14|0Updated：2025-02-13
- Abstract：Smart actuators and wearable and implantable devices have attracted much attention in healthcare and environmental sensing. Flexible electronic and ionic materials are the two main approaches used to construct these devices. Among them, hydrogel-based ionic materials offer unique advantages, such as biocompatibility and adaptable mechanical properties. However, ionic hydrogels encounter challenges in achieving wirelessly powered and noncontact sensing. To address this, we introduce MXene nanosheets to construct ionotronic hydrogels. Leveraging the rich surface charges and electronic conductivity of MXene nanosheets, ionotronic hydrogels can harvest vibrational and electromagnetic waves as electrical energy and enable noncontact sensing. Under ultrasound, it can continuously generate voltages up to 85 V and light up light-emitting diodes, promising wireless charging of implanted devices. In addition, it achieves an absorption coefficient of 0.2 for 915 MHz electromagnetic waves, enabling noncontact sensing through radio frequency identification. Notably, the physically crosslinked network of the MXene-based hydrogels maintained structural and performance stability under ultrasonic stimulation and exhibited self-healing properties. Even when cut into two halves, the self-healing hydrogel fully regenerates its original performance. This study provides insight into the development of ionotronic hydrogels for wirelessly powered and noncontact sensing in smart actuators and wearable and implantable applications.Keywords：Hydrogels;Ionotronics;MXene nanosheets;Energy harvesting;Noncontact sensing45|26|0Updated：2025-02-08
- Abstract：Stimuli-responsive shape-changing materials, particularly hydrogel and liquid crystal elastomer (LCE), have demonstrated significant potential for applications across various fields. Although intricate deformation and actuation behaviors have been obtained in either hydrogels or LCEs, they typically undergo reversible shape change only once (e.g., one expansion plus one contraction) during one heating/cooling cycle. Herein, we report a study of a novel liquid crystalline hydrogel (LCH) and the achievement of dual actuation in a single heating/cooling cycle by integrating the characteristics of thermoresponsive hydrogel and LCE. The dual actuation behavior arises from the reversible volume phase transition of poly(N-isopropylacrylamide) (PNIPAM) and the reversible order-disorder phase transition of LC mesogens in the LCH. Due to a temperature window separating the two transitions belonging to PNIPAM and LCE, LCH actuator can sequentially execute their respective actuation, thus deforming reversibly twice, during a heating/cooling cycle. The relative actuation degree of the two mechanisms is influenced by the mass ratio of PNIPAM to LCE in the LCH. Moreover, the initial shape of a bilayer actuator made with an active LCH layer and a passive polymer layer can be altered through hydration or dehydration of PNIPAM, which further modifies the dual actuation induced deformation. This work provides an example that shows the interest of developing LCH actuators.Keywords：Liquid crystalline hydrogel;Dual actuation;Thermoresponsive hydrogel;Liquid crystal elastomer64|37|0Updated：2024-11-25
- 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 films106|98|0Updated：2024-11-14
- Abstract：Fibers with deformation-triggered responses are essential for smart textiles and wearable electronics. Here, smart core-shell elastomer fibers with a conductive core and a liquid crystal elastomer shell showing simultaneous resistance and color responses are designed and prepared. The conductive core is consisted of interconnected liquid metal nanodroplets dispersed in a polymer matrix and the elastomer shell is made of cholesteric liquid crystals. When stretched, the fiber resistance increases as the interconnected pathways of liquid metal nanodroplets along the fiber axis become narrower, and the selective reflection color from the fiber surface blueshifts since the cholesteric pitch decreases. The smart elastomer fibers could be woven into smart textiles and respond to various mechanical deformations, including stretching, bending, compression and twisting. The average resistance change is 51% under 100% strain and its variation is smaller than 4% over 500 cycles, showing remarkable fatigue resistance. The simultaneous resistance and color responses to mechanical deformations make the fibers attractive for broad applications, such as flexible electronics.Keywords：Elastomer fiber;Core-shell;Simultaneous responses;Resistance;Color70|123|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;Functionalization130|127|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;Copolymerization89|95|0Updated：2024-11-07
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