Porous GNP/PDMS composites with significantly reduced percolation threshold of conductive filler for stretchable strain sensors

Porous structure engineering strategy shows great promising in achieving the improvement of sensing performance in flexible strain sensors. Herein we use a self-sacrificing templating method to prepare porous engineered graphene nanoplate/polydimethylsiloxane (GNP/PDMS) composites with segregated conductive network for flexible strain sensors, where green pore forming agent in conjunction with GNP conductive filler is used to shape the composite microstructure aiming to achieve the enhanced sensitivity, range of linearity as well as failure stretchability. Results demonstrate that 4 wt% GNP/PDMS composites show the most promising sensing performance with respect to both gauge factor and range of linearity. Moreover, significantly decreased percolation threshold of conductive filler GNP with the reduced value up to 100% is indicated in porous structured GNP/ PDMS composites (2 wt%) when compared to that of solid structured GNP/PDMS composites (over 4 wt%). This is attributed to the formed and stable segregated conductive network contributed by the piled-up GNP with sequenced microstructure when subjected to the external applied strain stimulus.