FORMATION AND CHARACTERIZATION OF SELF-ASSEMBLED FILMS OF THIOL-DERIVATIZED POLY(DIMETHYLSILOXANE) ON GOLD

Poly(dimethylsiloxane) (PDMS) copolymers containing propanethiol side chain ''stickers'' for forming self-assembled films on gold surfaces h ave been studied by Various experimental techniques including ellipsom etry, contact angle measurements, FT-IR, angle-dependent XPS, and ToF- SIMS. The results show that the thiol-containing side chains do not al l: chemisorb to the gold surfaces. In addition. the concentration of t hese sticker units was found to have a dominant effect on the polymer film thickness:. the surface wetting properties, and the orientation o f the PDMS backbone. Ab initio calculations reveal that the IR-active PDMS Si-O stretching bands can be used as indications of chain orienta tion, and a comparison of the calculated spectra with grazing incidenc e reflection IR data shows that the self-assembled PDMS backbone is pr edominantly aligned parallel to the surface, plausibly as a result of the chemisorption.