Kim Yewon, Song Jihyang, An Soojung, Shin Mikyung, Son Donghee
Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon 16419, Korea.
Polymers (Basel). 2022 Aug 20;14(16):3409. doi: 10.3390/polym14163409.
Liquid metals not only have the electrical property of conductivity, but they also have a unique characteristic of existing in a liquid state at room temperature, unlike ordinary stiff solid metals. However, in bioelectronics, the modulus matching well between a device and skin or tissue is considered very advantageous, because high-quality biological signals can be recorded. Therefore, it is possible to implement soft electronics with stable and robust electrical characteristics by using LM as a conductive liquid-state filler. In this study, we changed a type of liquid metal, Eutectic Gallium Indium (EGaIn), into a particle form via tip sonication and mixed it with a solution that dissolved Styrene-Ethylene-Butylene-Styrene (SEBS) in toluene to fabricate a composite. The EGaIn-SEBS composite has high conductivity, excellent electrical durability under mechanically harsh conditions, and a degree of modulus similar to that of bare SEBS, which is lower than that of solid-filler-based SEBS composite. Finally, we demonstrated electrocardiogram signal monitoring using an EGaIn-Alginate two-layer electrode (EATE) that was fabricated by simply coating the surface of the composite with alginate hydrogel, which demonstrates excellent performance in bioelectronics.
液态金属不仅具有导电的电学特性，而且与普通坚硬的固态金属不同，它们具有在室温下呈液态存在的独特特性。然而，在生物电子学中，器件与皮肤或组织之间良好的模量匹配被认为非常有利，因为这样可以记录高质量的生物信号。因此，通过使用液态金属（LM）作为导电液态填料，可以实现具有稳定且强大电学特性的柔性电子器件。在本研究中，我们通过尖端超声处理将一种液态金属，即共晶镓铟（EGaIn）转变为颗粒形式，并将其与一种在甲苯中溶解了苯乙烯-乙烯-丁烯-苯乙烯（SEBS）的溶液混合以制备复合材料。EGaIn-SEBS复合材料具有高导电性、在机械苛刻条件下优异的电耐久性，以及与纯SEBS相似的模量程度，该模量低于基于固体填料的SEBS复合材料。最后，我们展示了使用EGaIn-藻酸盐双层电极（EATE）进行心电图信号监测，该电极是通过简单地用藻酸盐水凝胶涂覆复合材料表面制成的，其在生物电子学中表现出优异的性能。
