AFM Observation of the Blocking of Step Motion on the (100) Face of an L-Asparatic Acid Crystal Caused by Tailor-Made Additives

Abstract

The blocking behavior of step motion on the (100) face of an L-asparatic acid (L-Asp) crystal caused by the doping of an amino acid in an aqueous solution was investigated using an atomic force microscope. The doping of amino acids with smaller (L-alanine) and larger (L-lysine, L-phenylalanine) side chains than those of the crystallizing species (L-Asp) caused a pinning of steps that have heights equivalent to the unit cell dimension along the a axis. On the other hand, amino acids with similar-sized side chains (L-asparagine and L-glutamic acid) had little effect.