Fig. 3

a Stress–strain curves of the pressure sensor based on various weight concentrations of bare PDMS (blue solid line), in this case 50 wt% (red dash line) and 30 wt% (black dot line) at 80% compressive strain. b Sequential loading–unloading cycles of PDMS-30 foam under compressive strain ranging from 20 to 80%. c Cyclic compression tests of the PDMS-30 foam sample at 60% compressive strain