Hierarchical Interfacial Assembly of ABC Triblock Copolymer

2008-03-19T00:00:00Z (GMT) by Jiwen Hu Guojun Liu Gabriel Nijkang
Hierarchical assembly, allowing molecular order and structural control at multilength scales, is the basis of life itself and may be used in the fabrication of future electronic, optical, and other devices. Despite its importance, hierarchical assembly has been seldom practiced for block copolymers in solvents. This paper reports a method for the two-tier assembly of block copolymers. At tier 1, an ABC triblock copolymer is self-assembled into spherical or cylindrical micelle-like aggregates in decahydronaphthalene (DN) with the B block making up the insoluble core and the A and C blocks making up the soluble corona. At tier 2, the aggregates are further assembled by adsorption via the Pickering effect on surfaces of droplets of methanol that is immiscible with DN, has been added into the DN aggregate solution, and solubilizes the C block but not the A and B blocks. While the final 3-D shape of the hierarchically assembled block copolymer is invariably spherical, the 2-D morphologies are different being ordered ribbons at 52 ± 2 °C and balls in sockets at 22 ± 2 °C.