CHARACTERIZATION of FILMS OBTAINED FROM PECVD of QxMy OLIGOSILOXANES

Recently, we have reported the application of PECVD (Plasma Enhanced Vapor Chemical Deposition) of hexamethyldisiloxane to protect quarry stones [1]. It has been demonstrated that plasma polymerization can be used to modify surface properties of substrates without affecting the bulk properties. This process is fast, uniform and cheap. Using this procedure, the use of VOC’s are avoided. In this work PEVCD of QM₄, Tetrakis(trimethylsilyloxy)silane has been used to generate thin films to improve the surface properties of different substrates(leather is an example). QM₄ (Q= SiO_4/2, M= (CH₃)₃SiO_1/2) was obtained by the trimethylsilylation reaction of natural silicates [2].
The substrates samples were exposed to siloxane plasma (QM₄ and HMDS) using different conditions for plasma potential and exposition time. In general the plasma polymerization deposition of QM₄ generates coatings with interesting properties. The main aspect to be discussed in this presentation is the film characterization. Several techniques have been used to fulfill such purpose: AFM, SEM, FTIR, contact angle, water vapor permeability. Particularly, the discussion will be focused on XPS data.

 The authors wish to acknowledge CONACYT-México for financial support.