A STUDY ON ADSORPTION STRUCTURES OF METHACRYLOYLOXYALKYL DIHYDROGEN PHOSPHATES ON SILVER SUBSTRATES BY INFRARED REFLECTION-ABSORPTION SPECTROSCOPY

10-Methacryloyloxydecyl dihydrogenphosphate (M1OP) for use in dentistr y has recently been noted as an adhesive monomer contained in a metal primer. Although the treatment of a metal surface with primer before t he application of resin is recognized to improve the adhesion between metal and resin, the role of M1OP in the adhesion process has not been clarified. In this study, infrared reflection absorption (IRA) spectr oscopy was employed to study the adsorption structures of M1OP as well as 2-methacryloyloxyethyl dihydrogen phosphate (M2P) on evaporated si lver substrates. The IRA spectra of the self-assembled films of those phosphates verified the adsorption of M1OP or M2P on silver substrates from the methyl methacrylate solutions (5 x 10(-5) mol/L). The satura tion coverages of M10F and M2P were completed after about 50 and 25 mi n, respectively. Two characteristic bands around 980 and 1080 cm(-1) d ue to the PO32- stretching vibrations were observed. These results ind icate that the phosphate groups of both monomers are adsorbed to silve r surfaces in the dissociated form -PO32-, and form hydrophobic monola yers. The monolayer of M10P was found to be more durable against therm ocycling in water than that of M2P by IRA measurements. The roles of M 10P in the metal primer are presumably to form such a monolayer with a ppreciable durability and to promote polymerization with resin monomer s. (C) 1997 John Wiley & Sons, Inc.