Hollow microspheres and aqueous phase behavior of pH-responsive poly(methyl methacrylate-co-methacrylic acid) copolymers with a blocky comonomer distribution

Copolymers of methyl methacrylate (MMA) and methacrylic acid (MAA) were prepared by partial hydrolysis of PMMA in bad solvent. These copolymers evidently have a blocky comonomer distribution –strands of predominantly MMA or MAA across the polymer– and show sharp transitions in aqueous solution upon pH change. Additionally, their hollow microcapsules show an exceptional and prolonged stability at acidic conditions (pH 2) and pH-triggered release at physiological conditions.