A flexible strain sensor of porous conductive silicone rubber composites prepared from high internal phase emulsion

In this work, a stretchable and compressible strain sensor was fabricated from conductive porous carbon nanotubes/polydimethylsiloxane (CNT/PDMS-P) high internal phase emulsion (HIPE), which was obtained by simple mechanical mixing of CNTs, PDMS, and water. Micropores were uniformly distributed in the PDMS matrix, with diameters mainly in the range of 3-9 mu m and averaging 5.3 mu m. Due to the confined dispersion of CNTs in the porous PDMS framework, the CNT/PDMS-P achieved a lower percolation threshold of 0.29 wt%. Compared to the non-porous composite (CNT/PDMS), its percolation threshold was reduced by 25%. Besides, the CNT/PDMS-P showed excellent sensitivity and cyclic stability. The sensitivity of CNT/PDMS-P was 50% higher than that of CNT/PDMS in the tensile strain range of 0%-10%. The stability tests for 1000 loading/unloading cycles showed that the maximum offset rate of CNT/PDMS-P was 58% lower than that of CNT/PDMS. The sensitivity of CNT/PDMS-P compression sensor was S = 0.00259 kPa(-1), which could detect the stress up to 600 kPa and maintain the standard waveform even after 1000 compression cycles. Finally, the potential application scenarios of the sensor, such as perception of human body limb movement, facial movement, gesture transformation, and human-computer interaction scenarios, were explored.

Automated summary

In this study, a stretchable and compressible strain sensor was developed using conductive porous carbon nanotubes/polydimethylsiloxane (CNT/PDMS-P) high internal phase emulsion (HIPE). The CNT/PDMS-P sensor exhibited lower percolation threshold, improved sensitivity, and cyclic stability compared to the non-porous composite (CNT/PDMS). The sensor also showed potential applications in various scenarios, such as human body movement perception, facial movement, gesture transformation, and human-computer interaction.