Synthesis of novel shell cross-linked micelles with hydrophilic cores

We review our recent progress in the synthesis of novel shell cross-linked knedel (SCK) micelles. The reversible self-assembly of hydrophilic-hydrophilic block copolymers in aqueous media is exploited in order to develop three new classes of SCK micelles. In each case the micelle cores can be tuned to become hydrophilic or hydrophobic depending on the solution pH, electrolyte concentration or temperature. In our initial studies (1), a tertiary amine methacrylate diblock copolymer was used to prepare SCK micelles of 20-40 nm diameter, with shell cross-linking being achieved using a bifunctional quaternizing agent. Secondly, an ampholytic diblock copolymer was used to prepare zwitterionic SCK micelles with two distinct particle morphologies: Type I micelles, which comprise cationic coronas and anionic cores and Type II micelles, which comprise anionic coronas and cationic cores (2). Finally, a novel tailor-made triblock copolymer was synthesized and utilized in SCK micelle syntheses at high solids (> 10 %) (3). This 'proof-of-concept' experiment suggests that commercial applications of these fascinating nanostructures may be a realistic possibility.