Chiang Mai Journal of Science

SF6 plasma has been used to improve the hydrophobic properties of Thai Silk. In this study, possible reactions were investigated via a glycine-alanine (GA) model; the main component that dominates intermolecular interactions reflecting the physical properties of silk. Quantum mechanical (QM) calculations using density functional theory (DFT) and molecular dynamic (MD) simulations were utilized to investigate possible mechanisms for the interaction between GA, fluorine radicals (F^•) and fluorine anions (F^-).  The hydrogen abstraction reactions of  radicals are the lowest activation energy pathways and should be the most preferable pathway in the plasma treatment process. From the MD simulation, the interaction energies of water with the silk surface and irradiated surface were -4.65 and -2.63 kcal/(mole of water), respectively