Crystallization Induced Self‐Assembly: A Strategy to Achieve Ultra‐Small Domain Sizes

Achieving self‐assembled nanostructures with ultra‐small feature sizes (e. g., below 5 nm) is an important prerequisite for the development of block copolymer lithography. In this work, the preparation and self‐assembly of a series of giant molecules composed of vinyl polyhedral oligomeric silsesquioxane (VPOSS) tethered with monodispersed oligo(L‐lactide) chains are presented. Small‐angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) results demonstrate that ultra‐small domain sizes (down to 3 nm) of phase separated lamellar morphology are achieved in bulk, driven by the strong tendency and fast kinetics for crystallization of VPOSS moieties. Moreover, upon gamma ray radiation, VPOSS cages in the lamellar structure can be crosslinked via polymerization of the vinyl groups. After pyrolysis at high temperature, ultra‐thin two‐dimensional nano‐silica sheets can be obtained. Lamellar morphologies with ultra‐small domain sizes (down to 3 nm) are achieved by the self‐assembly of giant molecules. The driven force for the phase separation is attributed to the strong tendency and fast kinetics for crystallization of vinyl polyhedral oligomeric silsesquioxane (VPOSS) segment. Upon the gamma ray radiation followed pyrolysis, ultra‐thin two dimensional nano‐silica sheets are obtained due to polymerization of vinyl group in VPOSS.