Watching block copolymer self-assembly with liquid phase transmission electron microscopy

Amphiphilic block copolymers in soln. can assembly into a wide range of colloidal materials, which have been widely investigated as drug delivery vehicles and catalytic nanoreactors. Due to their kinetically trapped nature, self-​assembly is often performed using the solvent switch protocol. While numerous exptl. and theor. investigations into the mechanism of self-​assembly have been conducted in an effort to gain more control over this process, there has never been a real-​time, real space investigation of the assembly process on the nanoscale. Here we present the first observation of block copolymer assembly via the solvent switch process using liq. phase transmission electron microscopy. We show the formation of polymer vesicles, cylindrical micelles and multicompartmental structures and discuss the different mechanisms of self-​assembly with supporting data from ex-​situ cryoTEM measurements and SCF (SCF) lattice computations