Interpolymer Hydrogen-Bonding Complexation Induced Micellization from Polystyrene-b-poly(methyl methacrylate) and PS(OH) in Toluene

In this paper, we suggest a new approach to macromolecular assembly by hydrogen-bonding complexation leading to a micelle-like structure from block copolymers in nonselective solvents. The hydrogen bonding between polystyrene - b -poly(methyl methacrylate) (PS - b -PMMA) and poly{styrene- co -[ p -(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl)ethyl-α-methylstyrene]} (PS(OH)) in toluene led to a stable core−shell structure with the core and shell, respectively, made of the insoluble PMMA/PS(OH) complexes and the soluble PS blocks as long as the p -(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl)ethyl-α-methylstyrene (HFMS) content of PS(OH) is higher than 8 mol %. Laser light scattering studies found that the molar mass and the core density of the complex micelles increased, but the size decreased as the HFMS content increased. The complexation-induced micelles were very stable, as dilution had almost no effect on them. However, both the size and molar mass of the complex micelles increased as the initial polymer concentration increased, indicating that the complexation was a diffusion-controlled process and the micellization process may not reach thermodynamic equilibrium. In addition, fluorescence and viscometry measurements further supported the concept of formation of hydrogen bonding complex micelles and their dependence on HFMS content in PS(OH).