Micellization of poly(2-vinylpyrridine)-b-poly(cyclohexyl methacrylate) (P2VP-b-PCHMA) block copolymers and their interpolymer complex formation in non-aqueous medium.

The interpolymer complex formation between poly(vinylpyridine)-based polymers with poly(acrylic acid) (PAA), in aqueous or organic medium, is driven by the hydrogen-bonding complexation. Well-defined nanostructures, with specific practical applications, may be obtained by taking advantage of such non-covalent interactions. Poly(2-vinylpyridine)-b-poly(cyclohexyl methacrylate) (P2VP-b-PCHMA) and poly(2-vinylpyridine)-b-poly(t-butyl methacrylate)-b-poly(cyclohexyl methacrylate) (P2VP-b-PtBuMA-b-PCHMA) copolymers were synthesized by sequential anionic polymerization. Their micellar characteristics were examined as a function of their molecular characteristics in methylcyclohexane and toluene respectively, as cycloaliphatic and aromatic solvents for the selective solubilization of the PCHMA sequence. The size of interpolymer complexes was determined by DLS, in 1,4 dioxane, and their structural composition was characterized by 1H NMR. The scaling relationship between the molecular composition and the micellar characteristics, such as particle size and aggregation number, could be established for the PCHMA-based copolymers in methylcyclohexane. It was further demonstrated that controlled micellization in 1,4 dioxane, as a non-selective organic solvent, could be achieved by hydrogen bond type interpolymer complex formation between P2VP-b-PCHMA and PAA-b-PCHMA under stoichiometric P2VP/PAA conditions. Finally, the size of the PCHMA-b-PAA/P2VP block copolymer/homopolymer complexes as well as of the PCHMA-b-PAA/PCHMA-b-P2VP block copolymer/block copolymer complexes was correlated with the molecular characteristics of the copolymers.