Xu Yindong, Sun Keyong, Huang Lingyi, Dai Yu, Zhang Xiaojin, Xia Fan
Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074, China.
ACS Appl Mater Interfaces. 2024 Feb 28;16(8):10556-10564. doi: 10.1021/acsami.3c19373. Epub 2024 Feb 15.
Janus hydrogels with different properties on the two surfaces have considerable potential in the field of material engineering applications. Various Janus hydrogels have been developed, but there are still some problems, such as stress mismatch caused by the double-layer structure and Janus failure caused by material diffusion in the gradient structure. Here, we report a Janus adhesive-tough hydrogel with polydopamine-decorated FeO nanoparticles (FeO@PDA) at one side induced by magnetic field to avoid uncontrollable material diffusion in the cross-linking polymerization of acrylamide with alginate-calcium. The magneto-induced Janus (MIJ) hydrogel has an adhesive surface and a tough bulk without an obvious interface to avoid stress mismatch. Due to the intrinsic dissipative matrix and the abundant catechol groups on the adhesive surface, it shows strong adhesion onto various substrates. The MIJ hydrogel has high sensitivity (GF = 0.842) in detecting tiny human motion. Owing to the synergy of FeO@PDA-enhanced interfacial adhesion and heat transfer, it is possible to quickly generate effective temperature differences when adhering to human skin. The MIJ hydrogel achieves a Seebeck coefficient of 13.01 mV·K and an output power of 462.02 mW·m at a 20 K temperature difference. This work proposes a novel strategy to construct Janus hydrogels for flexible wearable devices in human motion sensing and low-grade heat harvesting.
在两个表面具有不同性质的Janus水凝胶在材料工程应用领域具有巨大潜力。各种Janus水凝胶已被开发出来，但仍存在一些问题，例如双层结构导致的应力失配以及梯度结构中材料扩散引起的Janus失效。在此，我们报道了一种Janus粘性坚韧水凝胶，其一侧由磁场诱导含有聚多巴胺修饰的FeO纳米颗粒（FeO@PDA），以避免在丙烯酰胺与海藻酸钙的交联聚合过程中出现不可控的材料扩散。磁诱导Janus（MIJ）水凝胶具有粘性表面和坚韧的主体，没有明显的界面，可避免应力失配。由于其固有的耗散基质和粘性表面上丰富的儿茶酚基团，它在各种基材上表现出很强的粘附力。MIJ水凝胶在检测微小人体运动时具有高灵敏度（GF = 0.842）。由于FeO@PDA增强的界面粘附和热传递的协同作用，当粘附在人体皮肤上时，有可能快速产生有效的温度差。MIJ水凝胶在20 K的温差下实现了13.01 mV·K的塞贝克系数和462.02 mW·m的输出功率。这项工作提出了一种构建Janus水凝胶的新策略，用于人体运动传感和低品位热收集的柔性可穿戴设备。
