ADSORPTION OF PHOTOACTIVE AMPHIPHILIC POLYMERS ONTO HYDROPHOBIC POLYMER-FILMS - CK-POLY(2-VINYLNAPHTHALENE)-BLOCK-POLY(METHACRYLIC ACID)

Diblock polystyrene-block-poly(methacrylic acid) polymers have been sy nthesized using anionic polymerization techniques incorporating an ave rage of one naphthalene per polymer at either the beginning of the pol ystyrene block or at the junction between the polystyrene and poly(met hacrylic acid) blocks. These polymers have been shown in earlier work to form stable micelles in solvent mixtures from 80:20 dioxane/H2O to pure water. In the present paper we have examined the ability of these polymers to adsorb on polystyrene films and have used photophysical t echniques to deduce the exposure of the naphthalene group to the aqueo us phase. Scanning electron microscopy images demonstrate that the int act micelle adsorbs onto the polystyrene surface and can achieve a nea rly close-packed monolayer coverage. The micelles adhere tenaciously t o the polystyrene film and lower the contact angle of water from ca. 9 0-degrees for untreated polystyrene to 30-40-degrees after surface ads orption. The naphthalene groups at the polystyrene-poly(methacrylic ac id) junction are partially exposed to the aqueous phase while the naph thalene at the poly(styrene) end is totally protected.