<scp>pH</scp> and Temperature Dependence of Low‐Core <i>T</i>_g Micellar Structures Formed by <scp>PDMAEMA</scp>‐<i>b</i>‐<scp>PLMA</scp> Diblock Copolymers in Aqueous Solution

ABSTRACT A diblock copolymer featuring a hydrophobic block with a low glass transition temperature and a pH‐responsive, cationic block is synthesized and investigated with respect to its self‐assembly behavior in aqueous solution. The synthesis of the poly(lauryl methacrylate)‐ block ‐poly(2‐( N , N ‐dimethylamino) ethyl methacrylate) diblock copolymer PDMAEMA 60 ‐ b ‐PLMA 40 is carried out using reversible addition fragmentation chain transfer (RAFT) polymerization. Its self‐assembly in dilute aqueous solution at pH 7 is investigated using various light scattering methods. Micelles with a positive zeta potential are identified. Synchrotron small‐angle X‐ray scattering reveals changes in the inner structure of the micelles as a function of temperature and at pH values above, below and close to the p K a value of PDMAEMA (ca. 7.5). At all pH values, cigar‐shaped core–shell micelles are found. While the micellar size and shape hardly change with temperature at pH 5, temperature responsivity is observed at pH 7 and 10, resulting in, among others, a change of the core size. These structural changes are facilitated by the softness of the PLMA core. Such systems may be suitable for the co‐delivery of hydrophobic drugs and nucleic acids.