Association behavior of poly(methacrylic acid)-block-poly(methyl methacrylate) in aqueous medium:: Potentiometric and laser light scattering studies

The atom transfer radical polymerization technique was used to synthesize poly(methacrylic acid-block-methyl methacrylate) (P(MAA(102)-b-MMA(10))) copolymer in order to study the aggregation behavior in aqueous solution over the course of neutralization. A combination of static and dynamic light scattering (SLS, DLS) and potentiometric titration techniques were used to investigate the size and shape of the micelle at various degrees of neutralization. The hydrodynamic radius (R-h) determined from dynamic light scattering increases from similar to26 nm (for unneutralized) to similar to42 nm (for completely neutralized sample). Both potentiometric and laser light scattering studies indicate the formation of a core-shell micelle, The weighted average molecular weights of the polymer and micelle are 1.18 x 10(4) and 2.25 x 10(5) g/mol, respectively, which suggests that the aggregation number of the micelle is similar to20.