Templating the Nucleation of Calcium Oxalate Monohydrate via Micropatterned Self-Assembled Monolayers on Gold

Abstract

Controlling both the nucleation and the growth of crystalline materials requires the confinement of a space wherein nucleation is induced and necessitates transport of ions to the newly formed nucleus. Micropatterned self-assembled monolayers (µP SAMs) of alkanethiolates on gold have been used at length to mimic natural organic templates as they are a facile way to create spatially constrained microenvironments for nucleation and consequently control ion flow to active nucleation sites. Here, we present µP SAMs of ω-functionalized alkanethiolates on gold as effective templating agents for the nucleation of calcium oxalate monohydrate (COM). COM crystals nucleate on carboxyl-and hydroxyl-terminated µP SAMs at a critical ion concentration regardless of growth solution pH. Mixed µP SAMs of mercaptohexadecane (MHD) and mercaptohexadecanoic acid (MHA) nucleated lower densities of COM while decreasing average crystal size. Shortening SAM chain length from MHA to mercaptoundecanoic acid (MUA) nucleated fewer COM crystals with poorly defined faces, while µP hydroxyl-terminated SAMs both lowered the nucleation density and increased the size of the COM crystals.

Polymorph-Directing Seeding of Entacapone Crystallization in Aqueous/Acetone Solution Using a Self-Assembled Molecular Layer on Au (100)

“…30 However, these experiments have been mostly carried out on crystals grown on a template surface directly. 22,[25][26][27] To the authors' knowledge, there have been no studies, so far, which have shown the influence of surface templates on crystallization within the bulk solution and within a representative reaction vessel size.…”

“…Since then, there have been rather few papers regarding the crystallization of organic crystals by surfaces templating. However, inorganic crystals especially CaCO 3 ,− crystallized on templated surfaces have been found to result in different polymorphs having a variety of interesting crystal shapes.…”