Fabrication of a Sensitive Strain and Pressure Sensor from Gold Nanoparticle-Assembled 3D-Interconnected Graphene Microchannel-Embedded PDMS.

Manufacture of uniform, sensitive, and durable microtextured sensing materials is one of the greatest challenges for pressure sensors and electronic skins. Reported in this article is a gold nanoparticle-assembled, 3D-interconnected, graphene microchannel-embedded PDMS (3D GMC-PDMS) film for strain and pressure sensors. The film consists of porous nickel foam with its inner walls coated by multilayer graphene. Embedding in PDMS with etching removal of the Ni yields a 3D GMC-PDMS. Coating the inner walls with Au nanoparticles yields an Au nanoparticle-assembled 3D GMC-PDMS (AuNPs-GMC-PDMS) film, which is useful as an ultrasensitive pressure and strain sensor. This sensor exhibits a wide detection range (∼50 kPa) and ultrahigh sensitivity of 5.37, 1.56, and 0.5 kPa-1 in the ranges of <1, 1-10, and 10-50 kPa, respectively. Its lower detection limit is 4.4 Pa, its response time is 20 ms, and its strain factor is up to 15. Comparison of a AuNPs-GMC-PDMS film with a 3D GMC-PDMS film reveals a sensitivity improvement of 40 times in the 0-1 kPa pressure range and a gauge factor of more than 4 times in the 0-30% tensile strain range. The device has broad applications as a traditional or wearable medical sensor.