Controlled Synthesis of Methacrylic Acid-Methyl Acrylate Copolymers and Their Properties at Various Interfaces

Abstract

Conditions were found for controlled reversible addition-fragmentation chain-transfer radical polymerization to obtain narrow-dispersity gradient methacrylic acid-methyl acrylate copolymer (M_n = 1.59 × 10⁴). A copolymer of similar composition and molecular mass (M_n = 1.81 × 10⁴) with random distribution of units was obtained by radical copolymerization in the presence of dodecyl mercaptan. The behavior of the gradient and random copolymers, each containing ∼14 mol % methacrylic acid units, was studied in solutions, Langmuir monolayers, and Langmuir-Blodgett films. Several ranges of the existence of associates and micelles, preserved upon transfer in a Langmuir-Blodgett film, were revealed for the narrow-dispersity copolymer at the water-air interface depending on pH of the subphase. Associates in the form of ribbon structures and molecular ensembles of nanometric size (network structure with loop-like fragments) are observed in the AFM images of Langmuir-Blodgett films of the gradient and random copolymers, respectively.