Zhang Bing, Zhang Xu, Wan Kening, Zhu Jixin, Xu Jingsan, Zhang Chao, Liu Tianxi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Innovation Center for Textile Science and Technology, Donghua University, Shanghai 201620, China.
School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
Research (Wash D C). 2021 Apr 15;2021:9761625. doi: 10.34133/2021/9761625. eCollection 2021.
The construction of ionic conductive hydrogels with high transparency, excellent mechanical robustness, high toughness, and rapid self-recovery is highly desired yet challenging. Herein, a hydrogen-bonding network densification strategy is presented for preparing a highly stretchable and transparent poly(ionic liquid) hydrogel (PAM-r-MVIC) from the perspective of random copolymerization of 1-methyl-3-(4-vinylbenzyl) imidazolium chloride and acrylamide in water. Ascribing to the formation of a dense hydrogen-bonding network, the resultant PAM-r-MVIC exhibited an intrinsically high stretchability (>1000%) and compressibility (90%), fast self-recovery with high toughness (2950 kJ m), and excellent fatigue resistance with no deviation for 100 cycles. Dissipative particle dynamics simulations revealed that the orientation of hydrogen bonds along the stretching direction boosted mechanical strength and toughness, which were further proved by the restriction of molecular chain movements ascribing to the formation of a dense hydrogen-bonding network from mean square displacement calculations. Combining with high ionic conductivity over a wide temperature range and autonomous adhesion on various surfaces with tailored adhesive strength, the PAM-r-MVIC can readily work as a highly stretchable and healable ionic conductor for a capacitive/resistive bimodal sensor with self-adhesion, high sensitivity, excellent linearity, and great durability. This study might provide a new path of designing and fabricating ionic conductive hydrogels with high mechanical elasticity, high toughness, and excellent fatigue resilience for skin-inspired ionic sensors in detecting complex human motions.
构建具有高透明度、优异机械强度、高韧性和快速自我修复能力的离子导电水凝胶是人们迫切期望但又具有挑战性的。在此，从1-甲基-3-(4-乙烯基苄基)咪唑氯盐与丙烯酰胺在水中的无规共聚角度出发，提出了一种氢键网络致密化策略，用于制备高度可拉伸且透明的聚(离子液体)水凝胶(PAM-r-MVIC)。由于形成了致密的氢键网络，所得的PAM-r-MVIC表现出固有的高拉伸性(>1000%)和压缩性(90%)、具有高韧性(2950 kJ m)的快速自我修复能力以及优异的抗疲劳性，在100次循环中无偏差。耗散粒子动力学模拟表明，氢键沿拉伸方向的取向提高了机械强度和韧性，通过均方位移计算得出的分子链运动受限进一步证明了这一点，这归因于致密氢键网络的形成。结合在宽温度范围内的高离子电导率以及对各种表面具有定制粘附强度的自主粘附性，PAM-r-MVIC可以很容易地用作具有自粘附性、高灵敏度、优异线性度和高耐久性的电容式/电阻式双峰传感器的高度可拉伸且可自愈的离子导体。这项研究可能为设计和制造具有高机械弹性、高韧性和优异抗疲劳恢复能力的离子导电水凝胶提供一条新途径，用于受皮肤启发的离子传感器来检测复杂的人体运动。
