Self-Assembly Directed Organization of Nanodiamond During Ionic Liquid Crystalline Polymer Formation

The UV-initiated free radical polymerization of a lyotropic mesophase prepared by co-assembly of an aqueous mixture of an ionic liquid (IL) monomer, 3-decyl-1-vinylimidazolium chloride, in a dimethyl sulfoxide dispersion of an IL-monomer nanodiamond conjugate yields a well-ordered 2D hexagonally structured network-polymer composite. The IL monomer is covalently bound to carboxylated detonation diamond via ester-linked 3-decyl-1-vinylimidazolium bromide. Successful preparation of the amphiphile-functionalized nanodiamond is determined by ATR/FT-IR, thermogravimetric analysis, and small-angle X-ray scattering (SAXS). Mesophase and composite structure are evaluated by SAXS, revealing a columnar architecture composed of amphiphilic ionic liquid cylinders containing solvent-rich cores. Self-assembly directed site localization of the nanodiamond positions the particles in the alkyl chain continuum upon polymerization. The composite reversibly swells in ethanol allowing structural variation and modulation of the nanoparticle internal packing arrangement. This work demonstrates that through careful molecular design, self-organization and site-directed assembly of nanodiamond into chemically distinct regions of a nanostructured organogel can be achieved.