Micellization behavior of tertiary amine-methacrylate-based block copolymers characterized by small-angle X-ray scattering and dynamic light scattering

We have studied the micellization behavior of tertiary amine methacrylate-based diblock copolymers, comprising the hydrophobic poly[2-(diethylamino)ethyl methacrylate] (PDEA) and hydrophilic/polyelectrolyte poly[2-(dimethylamino)ethyl methacrylate] (PDMA) blocks. Revealed by small-angle X-ray scattering (SAXS) and dynamics light scattering, micelle size of the PDMAm–b–PDEAn diblock copolymer in aqueous solution depends sensitively on the comonomer ratio n/m, molecular weight Mw, solution temperature, and solution pH values. Aggregation number is found to follow an empirical relation of N ∝ (n/m)1.6, disregarding the molecular mass. With n/m = 0.5, Mw ≈ 12,000, and pH = 7.6, the diblock copolymer forms spherical core–shell micelles at 23 °C, with a PDEA-core radius of 52 Å, a PDMA-shell thickness of 27 Å, and an aggregation number of 127.