Lee Ling-Chieh, Huang Kang-Ting, Lin Yen-Ting, Jeng U-Ser, Wang Chia-Hsin, Tung Shih-Huang, Huang Chun-Jen, Liu Cheng-Liang
Department of Materials Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
Department of Chemical and Materials Engineering, National Central University, Taoyuan, 32001, Taiwan.
Small. 2024 Jun;20(24):e2311811. doi: 10.1002/smll.202311811. Epub 2024 Feb 19.
Amid growing interest in using body heat for electricity in wearables, creating stretchable devices poses a major challenge. Herein, a hydrogel composed of two core constituents, namely the negatively-charged 2-acrylamido-2-methylpropanesulfonic acid and the zwitterionic (ZI) sulfobetaine acrylamide, is engineered into a double-network hydrogel. This results in a significant enhancement in mechanical properties, with tensile stress and strain of up to 470.3 kPa and 106.6%, respectively. Moreover, the ZI nature of the polymer enables the fabrication of a device with polar thermoelectric properties by modulating the pH. Thus, the ionic Seebeck coefficient (S) of the ZI hydrogel ranges from -32.6 to 31.7 mV K as the pH is varied from 1 to 14, giving substantial figure of merit (ZT) values of 3.8 and 3.6, respectively. Moreover, a prototype stretchable ionic thermoelectric supercapacitor incorporating the ZI hydrogel exhibits notable power densities of 1.8 and 0.9 mW m at pH 1 and 14, respectively. Thus, the present work paves the way for the utilization of pH-sensitive, stretchable ZI hydrogels for thermoelectric applications, with a specific focus on harvesting low-grade waste heat within the temperature range of 25-40 °C.
在可穿戴设备中利用人体热量发电的兴趣日益浓厚的背景下，制造可拉伸设备构成了一项重大挑战。在此，一种由两种核心成分组成的水凝胶，即带负电荷的2-丙烯酰胺基-2-甲基丙烷磺酸和两性离子（ZI）磺基甜菜碱丙烯酰胺，被设计成一种双网络水凝胶。这导致其机械性能显著增强，拉伸应力和应变分别高达470.3 kPa和106.6%。此外，聚合物的ZI性质使得通过调节pH值能够制造具有极性热电特性的设备。因此，随着pH值从1变化到14，ZI水凝胶的离子塞贝克系数（S）在-32.6至31.7 mV K范围内，分别给出了高达3.8和3.6的显著优值（ZT）值。此外，一种包含ZI水凝胶的原型可拉伸离子热电器件超级电容器在pH值为1和14时分别表现出1.8和0.9 mW m的显著功率密度。因此，本工作为将pH敏感、可拉伸的ZI水凝胶用于热电应用铺平了道路，特别关注在25 - 40°C温度范围内收集低品位废热。
