MPTMS Treated Au/PDMS Membrane for Flexible and Stretchable Strain Sensors

Au/PDMS membranes are widely used to fabricate strain sensors which can detect input signals. An interfacial adhesion between metal films and polydimethylsiloxane (PDMS) substrates is one of the important factors determining the performance of strain sensors, in terms of robustness, reliability, and sensitivity. Here, we fabricate Au/PDMS membranes with (3-mercaptopropyl) trimethoxysilane (MPTMS) treatment. PDMS membranes were fabricated by spin-coating and the thickness was controlled by varying the spin rates. Au electrodes were deposited on the PDMS membrane by metal sputtering and the thickness was controlled by varying sputtering time. Owing to the MPTMS treatment, the interfacial adhesion between the Au electrode and the PDMS membrane was strengthened and the membrane was highly transparent. The Au electrode, fabricated with a sputtering time of 50 s, had the highest gauge factor at a maximum strain of ~0.7%, and the Au electrode fabricated with a sputtering time of 60 s had the maximum strain range among sputtering times of 50, 60, and 120 s. Our technique of using Au/PDMS with MPTMS treatment could be applied to the fabrication of strain sensors.