Fabrication of hierarchically porous structured PDMS composites and their application as a flexible capacitive pressure sensor

Pressure sensors for wearable electronics are mounted on irregular surfaces and exposed to various external stimuli. Therefore, the sensor should have a flexible structure and wide pressure measurement range along with high sensitivity. In this study, we fabricated hierarchically porous structured polydimethylsiloxane (PDMS) composites with a simple and cost-effective method using sugar particles and a water-in-oil emulsion. Hierarchically porous PDMS composites were employed as the dielectric layers of flexible capacitive pressure sensors. The capacitive pressure sensor presents a sensitivity 22.5 times higher (0.18 kPa(-1)) than the sensors using bulk PDMS with a wide measurement range (0-400 kPa). The finite element analysis was implemented to analyze the non-linearity of sensors by observing the compressive behavior of the PDMS composites. For the practical applications, finger attached-sensor, respiration monitoring system, and sensor array were tested, and the proposed sensors showed sufficient potential for application in wearable electronics.

Automated summary

In this study, hierarchically porous PDMS composites were fabricated for flexible capacitive pressure sensors, with high sensitivity and wide measurement range. Finite element analysis was used to analyze the non-linearity of the sensors, and practical applications such as finger attached-sensor, respiration monitoring system, and sensor array tests showed the potential of the proposed sensors in wearable electronics.