Easy Tuning of Surface and Optical Properties of PDMS Decorated by Ag Nanoparticles.

Herein, we report a systematic study on the wetting and optical properties of a PDMS surface coated by silver nanoparticles. A uniform Ag nanoparticles distribution onto PDMS membrane was obtained through dc room-temperature sputtering. The effect of sputtering current and PDMS mixing ratio between oligomer and curing agent was investigated by means of UV-vis spectroscopy and contact angle measurements. The results clearly show that the wettability and optical properties of the silver-coated elastomeric substrate were strongly affected by the sputtering current and by the PDMS composition with a marked decrease of the water contact angle and the spectral shift of well-defined plasmonic dips in the transmittance spectra related to the nanoparticles morphology. The finite element method was employed to model the optical experimental results. The observed tunable properties can find huge applications in several technological fields in which PDMS was usually employed as the structural and/or plasmonic active element.