A novel tunable grating fabricated with viscoelastic polymer (PDMS) and conductive polymer (PEDOT)

A tunable grating using viscoelastic PDMS (polydimethylsiloxane) and conductive polymer PEDOT (poly 3,4-ethylenedioxythiophene): PSS (polystyrenesulfonate) was designed and the fabrication process was developed. A sandwich structure (PEDOT: PSS/PDMS/Gold electrode) was utilized. By applying voltage between the PEDOT: PSS top film and the bottom interdigital gold electrode, the initial plane surface of polymers deforms into a sinusoidal grating. The PDMS material properties were tuned by modifying the network structure to obtain good actuation of the polymer, including large relief depth and fast response speed. The grating profile on the surface was observed with the maximum relief depth of 200 nm. The response time of the modulator can reach 250 μs.