X-ray photoelectron spectroscopic study of surface modification of silk under UV-irradiation

X-ray photoelectron spectroscopy was used to investigate the surface modification of SiLK* resin (*Trademark of the Dow Chemical Company) to improve its adhesion to metal. Irradiation with UV light (lambda = 172 nm) was found to be an effective method of restructuring the bonds of the surface atoms of SiLK*. That is, it easily breaks carbon bonds and produces active atomic oxygen from even trace amounts of oxygen in the atmosphere. The unbonded carbon then combines with the atomic oxygen, and some of the carbon may desorb in the form of CO and CO2. When Ta is deposited on as-prepared SiLK*, it readily reacts with the carbon on the surface of the SiLK*. However, modification of the surface of the SiLK* by UV irradiation before deposition of the Ta inhibits the reaction between carbon and Ta, resulting in the formation of a more metal-like Ta layer.