We reported the development of a transparent stretchable crack-enhanced microfluidic capacitive sensor array for use in E-skin applications. The microfluidic sensor was fabricated through a simple lamination process involving two silver nanowire (AgNW)-embedded rubbery microfluidic channels arranged in a crisscross fashion. The sensing performance was optimized by testing a variety of sensing liquids injected into the channels. External mechanical stimuli applied to the sensor induced the liquid to penetrate the deformed microcracks on the rubber channel surface. The increased interfacial contact area between the liquid and the nanowire electrodes increased the capacitance of the sensor. The device sensitivity was strongly related to both the initial fluid interface between the liquid and crack wall and the change in the contact length of the liquid and crack wall, which were simulated using the finite element method. The microfluidic sensor was shown to detect a wide range of pressures, 0.1-140 kPa. Ordinary human motions, including substantial as well as slight muscle movements, could be successively detected, and 2D color mappings of simultaneous external load sensing were collected. Our simple method of fabricating the microfluidic channels and the application of these channels to stretchable e-skin sensors offers an excellent sensing platform that is highly compatible with emerging medical and electronic applications.
Bibliographical noteFunding Information:
J.H.C. and D.H.K. were supported financially by a grant from the Center for Advanced Soft Electronics (CASE) under the Global Frontier Research Program (2013M3A6A5073177 and 2014M3A6A5060932), Korea. J.L. is appreciative of the support provided by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean Ministry of Science, ICT and Future Planning (2014M3C1B1033982).
© 2017 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)