Abstract
Recent works on crystallization processes of polymorphic modifications of long-chain stearic acid have been reviewed. Among three typical polymorphs, A, B and C, the latter two were investigated in more detail. First, the thermodynamic parameters in the crystallization processes, i.e, surface energies and solubilities of the polymorphic modifications, were reported. The surface energies of the low-indexed faces of C were found to have lower values than those of B. As for the solubility, it was experimentally found that B and C have the same value at 32℃; above this temperature the solubility of C is lower than that of B, while B has the lowest solubility below 32℃. A always showed the higher solubility than the other two polymorphs at any temperatures. This means that B is the low-temperature stable polymorph and C is the high-temperature stable one, and that A is always metastable. On the nucleation and growth of three polymorphs, B prevailed at lower temperatures and supersaturations, while A and C at higher supersaturations and temperatures.
