Fabrication of Highly Sensitive Porous Polydimethylsiloxane Pressure Sensor Through Control of Rheological Properties

Area of Science:

• Materials Science
• Polymer Science
• Sensor Technology

Background:

• Elastomers are crucial for flexible electronics, but enhancing their sensitivity to pressure variations remains a challenge.
• Improving the sensitivity of pressure sensors is vital for applications ranging from human-machine interfaces to health monitoring.

Purpose of the Study:

• To develop a highly sensitive pressure sensor using porous polydimethylsiloxane (PDMS).
• To investigate the effect of pore structure on the sensitivity of PDMS-based pressure sensors.

Main Methods:

• Pores were created in PDMS by emulsifying immiscible PDMS and water with a surfactant.
• Controlling water content allowed tuning of pore size, density, uniformity, and distribution (2D/3D).
• The sensitivity of porous PDMS was evaluated under varying low and high external pressure conditions.

Main Results:

• Porous PDMS demonstrated significantly enhanced sensitivity to low external pressures compared to non-porous PDMS.
• Sensitivity was approximately 10 times greater in porous PDMS under low-pressure conditions.
• The sensor successfully detected dynamic loading/unloading of a small object and human heartbeats.

Conclusions:

• A simple and cost-effective method using PDMS-water emulsion fabricates highly sensitive porous PDMS.
• This porous PDMS is effective for developing pressure sensors capable of detecting applied pressures and contact forces.
• The developed sensor shows promise for applications requiring sensitive tactile feedback and physiological monitoring.