Plasma polymerized TEOS films for nanochannels formation and sensor development

This work presents thin films obtained by plasma polymerization of tetraethoxysilane in two different reactors. FT-IR analysis showed that the films contain mainly SiOSi and OEt species. Contact angles formed by drops of water demonstrated the hydrophobic character of the film. However, water reacted with the films leading to EtOH and SiOH formation and to a complete loss of carbon. Ultraviolet exposure favored cross-linking between OEt radicals. Quartz crystal measurements (QCMs) showed that the films adsorb readily dodecane, hexane and water vapor. The adsorption capacity was greater for more polar and/or smaller molecules. The water permeation was probably due to the presence of microchannels with up to 200 إ diameter as identified by atomic force microscopy. Preliminary results showed that Cu2+ can permeate and be adsorbed by the channels if potential is applied through the film. The films obtained in this work could also be used on natural polymers, and in particular on grains, to avoid microorganism attack during storage but without any further problem with germination. The results presented in this paper indicate that the films produced are suitable for ultraviolet surface protection and nanofilter or sensors development.