Polymer Nanosheets from Supramolecular Assemblies of Conjugated Linoleic Acid-High Surface Area Adsorbents from Renewable Materials

We present a strategy for robustly cross-linking self-assembled lamellar mesophases made from plant-derived materials to generate polymer nanosheets decorated with a high density of functional groups. We formulate a supramoleclar complex by hydrogen-bonding conjugated linoleic acid moieties to a structure-directing tribasic aromatic core. The resulting constructs self-assemble into a thermotropic lamellar mesophase. Photo-cross-linking the mesophase with the aid of an acrylate cross-linker yields a polymeric material with high-fidelity retention of the lamellar mesophase structure. Transmission electron microscopy images demonstrate the preservation of the large area, highly ordered layered nanostructures in the polymer. Subsequent extraction of the tribasic core and neutralization of the carboxyl groups by NaOH result in exfoliation of polymer nanosheets with a uniform thickness of ∼3 nm. The nanosheets have a large specific area of ∼800 m²/g, are decorated by negatively charged carboxylate groups at a density of 4 nm^-2, and exhibit the ability to readily adsorb positively charged colloidal particles. The strategy as presented combines supramolecular self-assembly with the use of renewable or sustainably derived materials in a scalable manner. The resulting nanosheets have potential for use as adsorbents and, with further development, rheology modifiers.