Fig. 2From: Hollow polydimethylsiloxane (PDMS) foam with a 3D interconnected network for highly sensitive capacitive pressure sensorsa Porosity of the copper foam and the fabricated pressure sensors. SEM images are shown of b the copper foam and the pressure sensor based on c bare PDMS, d PDMS-50, e PDMS-30, and f the hollow structure of PDMS-30Back to article page