Modification of Mechanical Strength of Octadecylphosphonic Acid on Mica by Hydrogen Bombardment

Abstract

Well-controlled, well-ordered and uniform Octadecylphosphonic acid (OPA) LB films on cleaved mica surfaces was formed, and their mechanical properties were characterized. A novel technology has been pioneered which utilizes a kinematic collision driven hydrogen abstraction using hyperthermal hydrogen molecules to induce cross-linking of hydrocarbon chains. The hyperthermal hydrogen-driven approach with proton energy as low as 5eV can induce cross-linking of the adsorbed OPA and can modify the hydrocarbon long chain chemical bonding formula and the actual ordered Langmuir-Blodgett lattice into an array of clusters of the virgin film. By increasing the kinematics-driven reaction time at fixed bombardment energy and at a modified fluence which initiates the degree of cross-linking can control the nanocluster growth of OPA thin film. Consequently, with a controllable bombardment condition with a function of fluence can modify the cluster shape and modify the mechanical strength as well.