posted on 2018-12-19, 00:00authored byJin-Oh Kim, Se Young Kwon, Youngsoo Kim, Han Byul Choi, Jun Chang Yang, Jinwon Oh, Hyeon Seok Lee, Joo Yong Sim, Seunghwa Ryu, Steve Park
Electronic
skin are devices that mimic the functionalities of human
skin, which require high sensitivity, large dynamic range, high spatial
uniformity, low-cost and large-area processability, and the capacity
to differentiate various external inputs. We herein introduce a versatile
droplet-based microfluidic-assisted emulsion self-assembly process
to generate three-dimensional microstructure-based high-performance
capacitive and piezoresistive pressure sensors for electronic skin
applications. Our technique can generate uniformly sized micropores
that are self-assembled in an orderly close-packed manner over a large
area, which results in high spatial uniformity. The size of the micropores
can easily be tuned from 100 to 500 μm, through which sensitivity
and dynamic range were controlled as high as 0.86 kPa–1 and up to 100 kPa. Our device can be printed on curvilinear surfaces
and be molded into various shapes. We furthermore demonstrate that
by simultaneously utilizing capacitive and piezoresistive pressure
sensors, we can distinguish between pressure and temperature, or between
pressure and proximity. These demonstrations make our process and
sensors highly useful for a wide variety of electronic skin applications.