Polymeric cantilever integrated with PDMS/graphene composite strain sensor

This paper describes the mechanical and electricalcharacteristics of apolydimethylsiloxane(PDMS) cantilever integrated with a high-sensitivity strainsensor. The strainsensor isfabricated usingPDMS andgraphene flakes that are uniformly distributed in thePDMS. In order to prepare PDMS/graphenecomposite with uniformresistance, a tetrahydrofuran solution is used to decrease the viscosity of aPDMS basepolymer solution. A horn-type sonicator is then used to mix the basepolymer withgraphene flakes. Low viscosity of the basepolymer solution improves the reliability and reproducibility of the PDMS/graphenecomposite for strainsensor applications. After dicing thecomposite into the desiredsensor shape, a tensile test is performed. The experimental results show that thecomposite with a concentration of 30 wt.% exhibits a linear response up to a strain rate of 9%. Thegraphene concentration of the preparedmaterials affects the gauge factor, which at 20%graphene concentration reaches about 50, and with increasinggraphene concentration to 30% decreases to 9. Furthermore, photolithography,PDMS casting, and a stencil process are used tofabricate aPDMS cantilever with an integrated strainsensor. The change inresistance of the integrated PDMS/graphenesensor is characterized with respect to the displacement of the cantilever of within 500 μm. The experimental results confirmed that the prepared PDMS/graphene basedsensor has the potential for high-sensitivebiosensor applications.

Source: Review of Scientific Instruments - October 12, 2016 Category: Physics Authors: Young-Soo Choi, Min-Joo Gwak and Dong-Weon Lee Source Type: research