(250d) Nanoscale Clustering and Nucleation In Aqueous Glycine Solutions

We have experimentally studied nucleation of glycine from aqueous solutions. Undersaturated and supersaturated solutions were monitored using small angle x-ray scattering and static and dynamic light scattering as well as nanoparticle tracking analysis. In both undersaturated and supersaturated solutions we observed two populations of liquid phase nucleation precursors: molecular clusters on the order of a nanometre and much larger clusters on the order of hundreds of nanometres, their presence confirmed by both small angle x-ray and dynamic light scattering. Number density of large clusters was dependent on solution concentration as well as flow conditions to which solutions were exposed, and it correlated with induction times and numbers of glycine crystals produced from these solutions. We propose that the observed clusters are participating in a multistep pathway leading to nucleation of glycine crystals from aqueous solutions.