RSC Advances
·
2014
·Vol. 4
·期 100
·56791-56797
·
IF 3.708
Yulin Cui,Mei Tan,Aidi Zhu,Mingyu Guo
Strain hardening and high resilience are two unique mechanical characteristics of many soft biological hydrogels. However, these properties, especially the strain hardening behaviour, are generally not seen in synthetic polymer hydrogels. Here, hydrogels are prepared by free-radical copolymerization of acrylamide and chain-extended vinyl-modified pseudo-polyrotaxane, which acts as a multifunctional crosslinker. The reactive pseudo-polyrotaxane is based on a β-cyclodextrin monomer and amine-terminated PEG–PPG–PEG (Pluronic F127). The obtained hydrogels can be stretched from 10 to more than 26 times their original length before breaking and withstand a compression strain of 95% and even 98% without fracture. Tensile stretching tests show obvious strain hardening behaviours in high stretching and compression deformation regimes. The strain hardening behaviour in stretching deformation is considered to be the orientation and aggregation of the movable crosslinkers along the axial polymer backbone. Moreover, the formation of a second supramolecular network due to the chain-extension effect may also be responsible for it. Highly resilient behaviours with almost no hysteresis and residual strains are also observed even with a maximum strain of λ = 12 because of the inherent freely movable character of the crosslinkers.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Wenjie Zhang,Penghui Wang,Yi Hu,Qiang Chen,Bo Chi
Natural materials possess inherent multilength-scale structures, showcasing outstanding mechanical properties such as strain-stiffening, high damping, and shape-memory features under ambient conditions. Such integrated properties are highly desirable for advanced materials in biomedical devices and soft robots but remain challenging in synthetic materials. Herein, a novel strategy of sequential ion treatment is employed to introduce micro/nanoscale-ordered structures and molecular-scale stimulus responses into hydrogel-derived self-assembly fibers under ambient conditions. The treated fibers exhibit strain-stiffening properties with a high toughness of 257 MJ m −3 and 73% damping capacity comparable to spider silk. Owing to their cross-linking network and reversible secondary structure, those fibers exhibit outstanding water-stability, wet stretchability, and hydration-responsive shape-memory performance, with ultimate elongation of 407%, shape-fixity ratio of 94%, and shape-recovery rate of 97%. This work furthers the green fabrication of smart materials with multifunction and presents promising applications in diverse fields, including biomimetics and biomedicine.
研究领域:
材料科学
·
生物医学工程
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Yun Wu,Yiping Nie,Zhu Long,Pengxiang Si,Dan Zhang
Strain-stiffening hydrogels are essential in the development of ionic skin, as human skin possesses a strain-stiffening property for self-protection. Semicrystalline polymers such as poly(vinyl alcohol) (PVA) have been widely investigated to fabricate strain-stiffening hydrogels via freeze–thaw cycling or chemical cross-linking but with limited adjustable properties. Compared with PVA, polyvinylamine (PVAm) has a higher reactive activity, making it easier to achieve multifunctionalities including strain-stiffening in a PVAm hydrogel. However, the amine moieties in the backbone tend to be ionized and form strong ionic hydrogen bonds with water, resulting in difficulties in forming crystalline hydrogels by conventional methods. Herein, a one-pot method to induce crystallinity and achieve multifunctional hydrogel is devised via coacervation of PVAm. Different from a published coacervation method to fabricate hydrogels with various properties via noncovalent interactions between different chemicals, coacervation occurs between PVAm to form aggregated and loose PVAm in our devised system. Such a strategy lowers the amine–water binding energy in the polymer-dense phase to achieve crystallinity and subsequently the strain-stiffening property; meanwhile, self-healability, self-adhesion, and ionic conductivity can be realized in the polymer-loose phase. The obtained hydrogel integrates stretchability (∼1300% elongation), toughness (227 kPa), the strain-stiffening property (∼10 times increase), self-adhesion (90 J m–2), self-healability (∼80% healing efficiency in toughness), and ionic conductivity (0.22 mS m–1). This convenient strategy will open a new horizon to design multifunctional skin-mimic materials.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 4.1
Liu Fan,Huang Shao-Yong,Tang Jian,Chen Quan
In this study, we prepared unentangled and slightly entangled poly( L -lactic acid) telechelic ionomer samples ( M n =5 and 16 kg/mol) based on sodium sulfonate groups. The telechelic samples exhibit extremely slow crystallization kinetics below the melting temperature T m and above the glass transition temperature T g , which enables us to examine the linear viscoelasticity of the ionomer melt samples therein. The application of either the shear flow (at 85 °C) or elongational flow (between 70 and 90 °C) strongly accelerates the crystallization, leading to strong strain hardening and formation of highly oriented α crystals. Depending on the relative average rates of the strain-induced dissociation and strain-induced crystallization, the stress evolution can be classified into two cases, and the critical work for strain-induced crystallization is higher in case where the strain-induced dissociation occurs earlier than the strain-induced crystallization.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2022
·Vol. 23
·期 6
·3032
·
IF 6.208
Jie Gu,Yu Guo,Yiran Li,Juan Wang,Wei Wang,Yi Cao,Bin Xue
Strain-stiffening properties derived from biological tissue have been widely observed in biological hydrogels and are essential in mimicking natural tissues. Although strain-stiffening has been studied in various protein-based hydrogels, effective approaches for tuning the strain-stiffening properties of protein hydrogels have rarely been explored. Here, we demonstrated a new method to tune the strain-stiffening amplitudes of protein hydrogels. By adjusting the surface charge of proteins inside the hydrogel using negatively/positively charged molecules, the strain-stiffening amplitudes could be quantitively regulated. The strain-stiffening of the protein hydrogels could even be enhanced 5-fold under high deformations, while the bulk property, recovery ability and biocompatibility remained almost unchanged. The tuning of strain-stiffening amplitudes using different molecules or in different protein hydrogels was further proved to be feasible. We anticipate that surface charge adjustment of proteins in hydrogels represents a general principle to tune the strain-stiffening property and can find wide applications in regulating the mechanical behaviors of protein-based hydrogels.Keywords:protein hydrogel;strain-stiffening;electrical repulsion;surface charge;mechanical property
研究领域:
生物材料学
·
生物物理学
·
组织工程学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Jianbing Cui,Jiwei Chen,Zhongbin Ni,Weifu Dong,Mingqing Chen,Dongjian Shi
Recently, flexible wearable and implantable electronic devices have attracted enormous interest in biomedical applications. However, current bioelectronic systems have not solved the problem of mechanical mismatch of tissue–electrode interfaces. Therefore, the biomimetic hydrogel with tissue-like mechanical properties is highly desirable for flexible electronic devices. Herein, we propose a strategy to fabricate a biomimetic hydrogel with strain-stiffening property via regional chain entanglements. The strain-stiffening property of the biomimetic hydrogel is realized by embedding highly swollen poly(acrylate sodium) microgels to act as the microregions of dense entanglement in the soft polyacrylamide matrix. In addition, poly(acrylate sodium) microgels can release Na+ ions, endowing hydrogel with electrical signals to serve as strain sensors for detecting different human movements. The resultant sensors own a low Young’s modulus (22.61–112.45 kPa), high nominal tensile strength (0.99 MPa), and high sensitivity with a gauge factor up to 6.77 at strain of 300%. Based on its simple manufacture process, well mechanical matching suitability, and high sensitivity, the as-prepared sensor might have great potential for a wide range of large-scale applications such as wearable and implantable electronic devices.
研究领域:
生物医学工程
·
材料科学
·
柔性电子
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Jianbing Cui,Ruisheng Xu,Weifu Dong,Tatsuo Kaneko,Mingqing Chen,Dongjian Shi
Flexible materials with ionic conductivity and stretchability are indispensable in emerging fields of flexible electronic devices as sensing and protecting layers. However, designing robust sensing materials with skin-like compliance remains challenging because of the contradiction between softness and strength. Herein, inspired by the modulus-contrast hierarchical structure of biological skin, we fabricated a biomimetic hydrogel with strain-stiffening capability by embedding the stiff array of poly(acrylic acid) (PAAc) in the soft polyacrylamide (PAAm) hydrogel. The stress distribution in both stiff and soft domains can be regulated by changing the arrangement of patterns, thus improving the mechanical properties of the patterned hydrogel. As expected, the resulting patterned hydrogel showed its nonlinear mechanical properties, which afforded a high strength of 1.20 MPa while maintaining a low initial Young’s modulus of 31.0 kPa. Moreover, the array of PAAc enables the patterned hydrogel to possess protonic conductivity in the absence of additional ionic salts, thus endowing the patterned hydrogel with the ability to serve as a strain sensor for monitoring human motion.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Zhichao Xu,Hui Yu,Huayang Sun,Yingzi Yang
The aim of this study was to modify strain hardening cementitious composite (SHCC) using MXene nanosheets to further enhance its strength and ductility. The results showed that the addition of 0.03 wt% MXene nanosheets increased the compressive strength and tensile strain of SHCC by 18.04 % and 88.18 %, respectively. The mechanism of MXene nanosheets in improving the mechanical properties of SHCC was revealed by single fiber pullout test, micromechanical analysis, microstructure analysis and finite element analysis. Firstly, MXene nanosheets fill the pores inside the matrix, reduce the porosity of the matrix, disperse the stress, and inhibit the crack propagation, thus improving the compressive properties of SHCC. Secondly, when MXene nanosheets adhered to the fiber surface, they modified the interfacial properties between the fiber and the matrix, preventing fiber pullout and consequently improving the tensile ductility of SHCC.
研究领域:
材料科学
·
土木工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Huowen Chen,Fusheng Zhang,Zhuqin Zhang,Lijuan Zhang
Balancing softness with mechanical robustness remains a critical challenge in synthetic electronic sensors, restricting their practical utility. Herein, we propose a strain-stiffening eutectogel fabrication strategy featuring a biomimetic hierarchical bonding design inspired by mammalian skin. This system (DES-PAA@Al, deep eutectic solvent-polyacrylic gel) integrates weak intermolecular interactions for compliance ( E 1 = 2.9 × 10 −4 MPa/%) and robust Al 3+ -carboxyl coordination bonds within the PAA network to ensure structural integrity under extreme deformation. The optimized eutectogel achieves ultrafast gelation (<20 s) and a sevenfold modulus enhancement ( E 3 / E 1 = 7), synergistically combining ultra-stretchability ( λ = 1060 %), fatigue resistance (850 cycles), high sensitivity (gauge factor ( GF ) = 1.17), strain-stiffening behavior, and broad environmental adaptability (−60 °C to 80 °C). Mechanical testing, internal structural evaluation, and computational simulations elucidate the hierarchical bonding mechanism, revealing energy-dependent bonding interactions. These capabilities enable the eutectogel to gently conform to rough surfaces while maintaining durability, making it ideal for electronic skin (e-skin) applications. This work establishes a universal and facile in-situ approach for fabricating skin-like strain-stiffening eutectogels, advancing their potential in bioelectronic interfaces such as strain-resistive sensors and physiological signal monitoring (e.g., Electrocardiogram (ECG)).
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Wei Yu,Wenle Zheng,Shuaichuang Hua,Qinghai Zhang,Ziqi Zhang,Jianghua Zhao,Wenjing Yuan,Guoxian Li,Chuizhou Meng,Huichan Zhao,Shijie Guo
Dielectric elastomer actuators with high energy and power output, combined without pre-stretching treatment to simplify device fabrication, are highly desirable for soft robotics. Here, different from most studies that focus on modifying elastomers such as polyacrylates and silicones, the study designs a prestretch-free dielectric elastomer based on hydrogenated carboxylated nitrile butadiene rubber to reach a record-high energy density (564 J kg −1 ) and power density (5641 W kg −1 ), ≈15 times greater than natural muscle and three times greater than the state-of-the-art dielectric elastomers. This excellent performance arises from the synergistic polarization enhancement and strain stiffening overcoming the inherent trade-offs between electrical and mechanical properties, simultaneously endowing the elastomer with an extremely high dielectric constant ( ɛ r = 17, 100 Hz), ultralow mechanical loss (tan δ m = 0.04@1 Hz), and large electrical breakdown strength (105 V µm −1 ). The assembled 40-µm-thick actuator lifts a 200-g load with over 20% strain and maintains a stable power density of 4780 W kg −1 for 50 000 cycles. Furthermore, the actuators demonstrate diverse applications, including serving as biceps artificial muscles to achieve a 90° rotation angle at a speed of 360°/s and actuating a soft robot carrying a load 20 times its weight. These findings provide a different approach for developing high-performance dielectric elastomers to broaden their application in soft robotics.
研究领域:
软体机器人
·
材料科学
·
智能材料
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Zhiqiang Wang,Lujun Zhang,Jiajun Feng,Pengfei Tang,Shuaishuai Chen,Hanqing Yu,Yueyao Hu,Zhongkai Wang,Feng Jiang
In this work, a chitin-based macromolecular chain transfer agent (Chitin-CTA) was designed to graft polymers from chitin at the molecular level. Homogeneous reversible addition-fragmentation chain transfer (RAFT) polymerization was performed to prepare branched MA elastomers , chitin- graft -poly(methyl acrylate) (Chitin- g -PMA) copolymers , which were thermally stable and showed tunable glass transition temperatures . These ultra-stretchable branched MA elastomers exhibit unique strain-hardening behavior and significantly enhanced mechanical properties. Mechanical tests indicate that the chitin backbones in branched MA elastomers can act as cross-linking points to improve the tensile strength , toughness, and elasticity simultaneously. The macroscopic performance of branched MA elastomers c be further promoted by introducing hydrogen bonding as non-covalent interaction to form an additional reversible physical network. This robust and versatile grafting strategy can provide new opportunities to prepare chitin-based branched MA elastomers with extraordinary mechanical properties.
研究领域:
材料科学
·
高分子化学
·
机械工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Xiaorong Dou,Zheqi Chen,Fuhao Ren,Lijun He,Jianxiong Chen,Li-Juan Yin,Yingwu Luo,Zhi-Min Dang,Jie Mao
Dielectric elastomer actuators (DEAs) face an acknowledged challenge: On the one hand, the majority of elastomers only achieve small electroactive deformation (<20%) in the absence of prestretch; on the other hand, rare elastomers capable of showing large electroactive deformation require relatively complicated processing and chemistry. This work addresses this challenge by fabricating an elastomer with a network of large side groups, which achieves a very large electroactive deformation (218%) without pre-stretch. This elastomer can be rapidly and massively fabricated within a few min, by polymerizing a commercial monomer with a large alkyl side group. The large side groups in the polymer network repel each other and extend the load-bearing strands, which results in a pronounced strain-hardening behavior. This behavior helps the elastomer to get rid of electromechanical instability during actuation and hence to exhibit a large electro-active deformation, a high energy density (>> human muscle), and a large output force (≈500 times self-weight). the elastomer capable of manufacturing a soft electroactive gripper is demonstrated with large deformation, large force, and rapid response, which enables grasping fragile objects of various complex shapes in an agile away.
研究领域:
材料科学
·
软体机器人技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）