Wettability of porous polydimethylsiloxane surface: morphology study

Two methods used for producing porous polydimethylsiloxane (PDMS) surfaces. In the first method, PDMS films without photosensitizer was exposed to CO2-pulsed laser at room temperature, as the excitation source. In the second method applying NaCl solid particles to the external surface layer before it is cured. In this study the morphology, wettability and surface chemical characteristics have been investigated. These surfaces have been studied by performing scanning electron microscopy (SEM) and attenuated total reflectance infrared (ATR-FTIR) spectroscopy. To evaluate the surface wettability, the water drop contact angle was measured. SEM photomicrographs and ATR-FTIR spectra and water drop contact angle measurement show that the morphology of these surfaces change to a uniform porous surface and wettability decreased. Results indicated that the porosity and morphology are important factor in wettability of PDMS surface and laser irradiation cause ordering in molecular chains onto the PDMS surface and this surface is a superhydrophobic compared to the virgin PDMS surface.