干旱区生态环境知识资源中心

The use of intrinsically soft conductors, such as gallium-based liquid metal (eutectic gallium-indium alloy, EGaln), has enabled bioinspired and skin-like soft electronics. Thereby, creating patterned, smooth, and uniform EGaln thin films with high resolution and size scalability is one of the primary technical hurdles. Soft lithography using wetting/nonwetting surface modifications and 3D heterogeneous integration can address current EGaln patterning challenges. This paper demonstrates multiscale and uniform EGaln thin-film patterning by utilizing an additive stamping process for large-scale (mm-cm) soft electronics and a subtractive reverse stamping process for microscale (mu m-mm) soft electronics. While EGaln patterning based on stamping is regarded as the least reliable patterning technique, this paper highlights multiscale and uniform thin-film patterning by stamping at room temperature and under atmospheric pressure utilizing proper chemical/physical surface modification to obtain selective nonwetting or uniform wetting properties. By combining structures fabricated using these additive and subtractive stamping techniques with 3D heterogeneous integration, functional soft microsystems are demonstrated: i) a soft LC (inductor-capacitor) sensing platform with high areal capacitance, ii) a fingertip-mountable biological sensing platform, arid iii) soft heaters with localized and distributed heating capability. The demonstrated fabrication and integration approaches enable high-density and multifunctional soft microsystems for versatile sensing applications.