QUANTITATIVE-ANALYSIS OF THE SI-H GROUPS FORMED ON POLY(DIMETHYLSILOXANE) SURFACES - AN ATR FTIR APPROACH

Attenuated total reflectance Fourier transform infra-red (ATR FTi.r.) spectroscopy was utilized to quantify the concentration of Si-H groups formed on poly (dimethylsiloxane) (PDMS) elastomer surfaces as a result of Ar or N2 plasma modifications. Kramers-Kronig transformation of the ATR spectra of standard solutions containing Si-H species allows construction of calibration plots which are independent of the angle of incidence, crystal coverage and sample refractive index. The Si-H concentrations of the plasma-treated PDMS are calculated from the calibration plots, and indicate that gas/plasma treatments of PDMS substrates result in Si-H functionality gradients with higher concentrations near the elastomer surface.