SURFACE MOLECULAR TAILORING VIA PULSED PLASMA-GENERATED ACRYLOYL CHLORIDE POLYMERS - SYNTHESIS AND REACTIVITY

A variable-duty cycle-pulsed radio frequency discharge is shown to pro vide film chemistry control during plasma polymerization of acryloyl c hloride. A nonlinear dependence is observed between the percent retent ion of acid chloride groups in the deposited films and the average pow er input during plasma polymerization. Significant C(O)C1 group retent ion is observed only under conditions of exceptionally low power input , as made available in the pulsed experiments. Additionally, relativel y large scale systematic changes in surface morphology and film format ion rates are observed with sequential variations in the plasma duty c ycle employed during film formation. Specifically, film surface roughn ess decreases and the film thickness per joule of input energy increas es as the plasma duty cycles employed are decreased. The plasma-genera ted films were employed in subsequent chemical reactions to attach tar get molecules to the substrate surfaces via facile reactions with the surface acid chloride groups. This concept is illustrated in the prese nt paper with reactions of 1,1,1-trifluoroethanol and allylamine with the plasma-modified surfaces. The results obtained are supportive of t he use of the ultralow-energy pulsed plasma technique to introduce rea ctive surface groups, followed by subsequent covalent coupling of targ et molecules, as a viable new route to molecular tailoring of surfaces .