A Gradient Stiffness‐Programmed Circuit Board by Spatially Controlled Phase‐Transition of Supercooled Hydrogel for Stretchable Electronics Integration

• DOI: 10.1002/adma.202313344
• Publication Date: 2024-02-21T13:09:10Z
• Authors: Minwoo Kim; Sangwoo Hong; Jung Jae Park; Yeongju Jung; Seok Hwan Choi; Chulmin Cho; Inho Ha; Phillip Won; Carmel Majidi; Seung Hwan Ko
• Keywords: Supercooling; Flexible Electronics; Stretchable electronics

Due to emerging demands in soft electronics, there is an increasing need for material architectures that support robust interfacing between substrates, stretchable electrical interconnects, and embedded rigid microelectronics chips. Though researchers have adopted rigid-island structures solve the issue, this approach merely shifts stress concentrations from chip-conductor interfaces rigid-island-soft region substrate. Here, a gradient stiffness-programmed circuit board (GS-PCB) possesses high stretchability stability with surface mounted chips introduced. The comprises hydrogel substrate laser-patterned liquid metal conductor. simultaneously obtains large stiffness disparity rigid-islands regions. These seemingly contradictory conditions are accomplished by adopting structure at interfaces, enabled combining polymers different interaction energies supercooled sodium acetate solution. By integrating gel exceptional properties, GS-PCB exhibits higher electromechanical than other research. To highlight practicality of approach, finger-sensor device successfully distinguishes objects direct physical contact fabricated, demonstrating its under various mechanical disturbances.