Surface functionalization in combination with confinement for crystallization from undersaturated solutions

Abstract

Crystallization from undersaturated solutions was demonstrated using functionalized nanoporous silica (Zorbax® chromatographic media). The silica matrix acts as a source of bound groups within the nanopores which act to reduce the solubility within the small pore volume resulting in the formation of nanocrystals within the pores. Experiments were conducted within sealed capillaries which were monitored via X-ray powder diffraction. Experiments were conducted for a number of solutes and concentrations and clearly demonstrated a critical concentration in the undersaturated region below which crystals would not form. Concentrations above this critical concentration would form crystals. Batch experiments confirmed that the crystallization yield could be calculated from the difference between the initial concentration before the addition of Zorbax® and the critical (effective saturation) concentration.