Analysis of growth habits of polar organic crystal N-4-nitrophenyl-(L)-prolinol (NPP) based on the incorporation of growth units

The growth habits of the polar organic crystal N-4-nitrophenyl-(L)-prolinol (NPP) in organic solvents have been studied from the standpoint of the incorporation of growth units. Qualitative explanations of the observed growth forms are based on (1) the interaction between the solvent molecules and the growth units, and (2) the influence of the solvent molecules on growth interfaces, particularly on two polar faces of the polar organic crystal. Since the incorporation rates of the growth units are different on positive and negative polar faces, a variety of growth habits appear. The surface structures of the grown crystal have been investigated through ex-situ observations of atomic force microscopy (AFM).