Highly Stretchable Resistive Pressure Sensors Using Conductive Elastomeric Composites on Micropyramid Array

Abstract: Stretching a pressure sensor without compromising its pressure sensitivity is still a very challenging task, as can be seen from highly sensitive pressure sensors which are only bendable but not stretchable. Here, we demonstrate a stretchable resistive pressure sensor based on a highly stretchable poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/polyurethane electrode surface-coated on a spring-like compressible micro-pyramid structured polydimethylsiloxane (PDMS) substrate. The resistive pressure sensor outperforms its capacitive-mode counterpart by exhibiting about 9 times better sensitivity (4.9 kPa-1) and 4 times wider linear response at low pressure regime (0.4~5.9 kPa). The reformulated PEDOT:PSS/ polyurethane composite polymer is highly conductive yet stretchable, enabling the sensor to be stretched up to 40 ％ strain. Most importantly, this highly stretchable sensor shows a pressure sensitivity which improves with stretching, recording a 10.3 kPa-1 sensitivity at 40 ％ elongation.