1 research outputs found
Interfacial Structure Analysis for the Morphology Prediction of Adipic Acid Crystals from Aqueous Solution
Adipic
acid crystals grown from aqueous solutions have a hexagonal
plate morphology with a dominant (100) face, where the hydrogen-bonding
carboxylic acid groups are exposed. In the present work, the crystal
morphology was investigated by interfacial structure analysis to obtain
the relative growth rates for the spiral growth model. The concentration
of effective growth units at the interface was found to be the key
external habit-controlling factor by molecular dynamics simulations
at the crystal–solution interface. The differences between
the experimentally observed faces of (002), (100), and (011) and unobserved
faces of (111Ì…), (102Ì…), and (202Ì…) were explained
by two concepts from the interfacial structure analysis that determine
the concentration of the effective growth units. The observed faces
were characterized by larger values of both the surface scaling factor
and molecular orientation factor, implying low anisotropic local concentrations
at the interface and high free energy barriers for reorientation on
these faces, respectively. Furthermore, the number of turns and the
length of one complete spiral rotation and the number of unsaturated
bonds were incorporated into the original approach. This consideration
of the spiral geometry resulted in a close resemblance to the experimental
morphology