Driven by the incompatibility between different blocks, block copolymers self-assemble into a wide range of morphologies, from simple lamellae, spheres and cylinders to more complex triply periodic bicontinuous structures. While the general phase behavior of block copolymers is very well understood, both theoretically and experimentally, allowing for tuning the morphology and structural dimensions, some morphologies remain elusive. The single diamond phase (space group <i>Fd-3m</i>) for instance, has never been achieved experimentally despite theoretical predictions. This phase, which is ubiquitous in nature, is of particular interest in the field of photonics, where it is known as the “champion” structure with the largest known photonic bandgap. Here we present the first truly polymeric self-assembled diamond and show that triblock terpolymers can self-assemble into single diamonds in films upon slow solvent evaporation (SVA). The morphology was identified and characterized using state-of-the-art tomography techniques (FIB-SEM slice-and-view and X-ray ptychography) with unprecedented resolution. Not only does this finding hold great promise for future photonic applications, we also believe that recent improvements in the tomography techniques employed here will enable the precise characterization of three-dimensional nanostructured matter, potentially enabling the identification of other new phases.

Controlled self-assembly of triblock terpolymer films into single diamond networks and their identification via nano-tomography

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.