In-plane modulus of singular 2:1 clay lamellae applying a simple wrinkling technique.

Knowledge of the mechanical properties of singular clay lamellae is of crucial importance for the optimization of clay-polymer nanocomposites. On the basis of controlled stress release, singular 2:1 clay lamellae show regular wrinkles on a deformable substrate. A subsequent two-dimensional Fourier transformation gives an in-plane modulus of the clay lamella of approximately 150 GPa. Only readily-available topographical atomic force microscopy is required for analysis rendering that fast and facile procedure generally applicable for nanoplatelet characterization.

Nanoplatelets of sodium hectorite showing aspect ratios of ≈20,000 and superior purity.

Applying a combination of melt synthesis followed by long-term annealing a fluorohectorite is obtained which is unique with respect to homogeneity, purity, and particle size. Counterintuitively, the hectorite undergoes a disorder-to-order transition upon swelling to the level of the bilayer hydrate. Alkylammonium-exchanged samples show at any chain length only a single basal spacing corroborating a nicely homogeneous layer charge density. Its intracrystalline reactivity improves greatly upon annealing, making it capable to spontaneously and completely disintegrate into single clay lamellae of 1 nm thickness. Realizing exceptional aspect ratios of around 20,000 upon delamination, this synthetic clay will offer unprecedented potential as functional filler in highly transparent nanocomposites with superior gas barrier and mechanical properties.