Graftlike interpolymer complexes from poly(2-vinylpyridine) and end-sulfonic acid polystyrene and polyisoprene: Intermediates to noncovalently bonded block copolymer-like micelles

The complexation between narrow molecular weight distribution poly(2-vinylpyridine) (P2VP) and polystyrene (suPS) or polyisoprene (suPI) end-functionalized with one sulfonic acid group was examined in tetrahydrofuran dilute solutions by a combination of static and dynamic laser light scattering. Both apparent weight-average molecular weight (M-w,M-app) and hydrodynamic radius (R-h) of the complexes exhibited a maximum at a certain molar ratio of suPS chains to P2VP monomeric units. This indicated that the P2VP backbone may be saturated by the grafted end-functionalized chains because of repulsion between the grafted chains. By changing the molar mass of P2VP from 100,000 to 30,000 g/mol, the values of M-w,M-app and R-h decreased. When suPI was used instead of suPS, similar trends were observed. In the latter case, it was possible to prepare block copolymer-like micelles by transferring the P2VP/suPI blend solutions in decane, which is a selective solvent for PI. The non-covalent-bonded polymeric micelle characteristics were investigated as a function of sulfonic acid/2-vinylpyridine units ratio as well as temperature. (C) 2003 Wiley Periodicals, Inc.