Fabrication of a Methacrylic Photo-adhesive Material Incorporating Hydroxypyridyl Groups

For preparation of our all-purpose photo-adhesive material, a methacrylic monomer bearing a hydroxypyridyl group was synthesized. Hydroxypyridyl groups take keto-enol tautomerization reactions according to their micro-environments, and adaptation of the molecular structures for strong interaction (or adhesion) would be expected. A photo-adhesive material was fabricated with the methacrylic monomer, 2-hydroxyethyl methacrylate, and a radical photo-initiator. Photo-adhesion experiments were performed by 2 J/cm2 of UV irradiation (50 mW/cm2) at a wavelength of 365 nm, resulting in higher values of shear stress in cases adding the monomer. It was found that a hydroxypyridyl group of the monomer existed mainly in the keto isomer in a solution of UV-Vis spectral measurements. On the other hand, results on XPS measurements suggested that a part of hydroxypyridyl groups could exist as the enol isomer in the adhesive residue.