Authors: R. Dey
Affilation: The university of waterloo, Canada
Pages: 824 - 827
Keywords: Langmuir-Blodgett film, atomic force microscopy, self-assembled monolayers, Octadecylphosphonic acid, silicon wafer, X-ray photoelectron spectroscopy, contact angle, surface energy, hydrogen bombardment, cross-linking
We report on surface modification with hyperthermal hydrogen induced cross-linking (HHIC) technology on uniform and well-ordered octadecylphosphonic acid (OPA) Langmuir-Blodgett (LB) films on several surfaces, and on surface characterizations of its properties. The hyperthermal hydrogen projectile with a kinetic energy of ~19 eV can induce cross-linking of the adsorbed OPA, which modifies the alkyl chain bonding and the OPA LB film into an array of clusters. By varying the fluence of the hydrogen projectile bombardment, the degree of cross-linking of OPA nanoclusters can be controlled. The OPA LB film on oxidized Al was the most promising system because I found that a cohesive and strongly adsorbed molecular layer can be achieved under the cross-linking. In comparison, likely due to their weaker OPA-headgroup-substrate interaction, OPA LB films on mica and silicon oxide surfaces were not as stable as OPA on oxidized Al. The cross-linking induced by the intermolecular C-C bonds was found to be strong enough to change OPA monolayer morphology drastically.