  Block copolymers are recognised as a valuable platform for creating
nanostructured materials with unique properties. Morphologies formed by block
copolymer self-assembly can be transferred into a wide range of inorganic
materials, enabling applications including energy storage and metamaterials.
However, imaging of the underlying, often complex, nanostructures in large
volumes has remained a challenge, limiting progress in materials development.
Taking advantage of recent advances in X-ray nanotomography, we non-invasively
imaged exceptionally large volumes of nanostructured soft materials at high
resolution, revealing a single diamond morphology in a triblock terpolymer
composite network. This morphology, which is ubiquitous in nature, has so far
remained elusive in block copolymers, despite its potential to create materials
with large photonic bandgaps. The discovery was made possible by the precise
analysis of distortions in a large volume of the self-assembled diamond
network, which are difficult to unambiguously assess using traditional
characterisation tools. We anticipate that high-resolution X-ray
nanotomography, which allows imaging of much larger sample volumes than
electron-based tomography, will become a powerful tool for the quantitative
analysis of complex nanostructures and that structures such as the triblock
terpolymer-directed single diamond will enable the generation of advanced
multicomponent composites with hitherto unknown property profiles.
