Excimer laser induced photochemical defluorination and substitution of functional group onto fluororesin surface for adhesion

Abstract

A powerful adhesion of fluororesin (Teflon) featuring its excellent corrosion resistance and stainless steel was performed by using an epoxy resin-based bonding agent. Adhesion strength was 500 times more than that of untreated teflon, which has virtually no affinity with chemicals and solids. The teflon surface was irradiated by an ArF excimer laser light with energy higher than the carbon-fluorine bond, in a tetrahydroborate (BNaH4) and methyl alcohol (CH3OH) mixed solution ambient. The defluorination of the surface was performed with the boron atoms which were photodissociated from BNaH4. The fluorine atoms of the surface was replaced with the CH3 and OH radicals, also photo dissociated from CH3OH. The methyl(-CH3) and hydroxyl(-OH) groups, which have a good affinity with epoxy bonding agent, were substituted only for the area exposed to the laser light. The modified teflon surface was adhered to a stainless steel with the epoxy bonding agent, and shearing tensile strength test was performed. The strength was 100 Kgf/cm2, whereas untreated teflon's strength is 0.2 Kgf/cm2 or less. Thus the adhesion was improved considerably.