Double-Gyroid Network Morphology formed by Asymmetric Magic-Ratio Block Oligomers

Amphiphilic block oligomers self-assemble into thermotropic liquid crystals with a variety of morphologies, such as lamellae, hexagonally-packed cylinders, and ordered spherical micelle packings. Among these phases, three-dimensional network structures are seldom found due to narrow composition and temperature phase windows over which they form. In this work, we designed a family of amphiphilic triblock oligomers comprising two asymmetric hydrophobic tails based on geometric analysis and assess their self-assembly in molecular dynamics simulations. With a comprehensive exploration, stable double gyroid morphologies are observed in the self-assembly of oligomers with a "magic" 1:2 tail length ratio. By changing the lengths of the tails while keeping the same headgroup, systematic explorations of the morphologies formed at different volume fractions indicate that this magic ratio for double gyroid stability is a robust molecular design across many volume fractions. This work demonstrates a new approach for designing amphiphilic block oligomers and stabilizing cubic network structures, which could lead to insights into the shape-filling mechanism of network phase formation and amphiphilic self-assembly.