In-situ liquid phase imaging of block copolymer vesicle assembly

Amphiphilic block copolymers in aqueous solution can assemble into various ordered molecular architectures, which have a wide range of applications in, for example, drug delivery and catalytic nanoreactors.1 While sustained efforts, both experimentally and theoretically, have been made to better understand the mechanism of self- assembly in order to gain more control over this process,2, 3 there has never been a real-time, real space investigation of the assembly process on the nanoscale. Here we show the first observation of block copolymer vesicle assembly via the solvent switch protocol4 using liquid phase transmission electron microscopy (LP-TEM). We also discuss the different mechanisms of self-assembly with the ex-situ cryo-TEM observation and compare them with self-consistent field (SCF) lattice calculations. Our findings illustrate the ability of LP-TEM to implement quantitative visualization of local formation process of the block copolymer vesicles to reveal the formation mechanism on an individual particle level Please click Additional Files below to see the full abstract