Multifaceted Roles of Additives in Regulating Crystal Growth: A Case of Acephate

Regulating crystal growth to obtain crystals with different sizes is of great importance for both natural and industrial processes. In this study, the complex influence of additives on crystal growth was systematically investigated using acephate as a model compound. The kinetics of crystal growth in the presence of various small molecule additives, including cetyltrimethylammonium bromide (CTAB), acetamide, thioacetamide, and benzoic acid, were analyzed. The effects of these additives on solubility, morphology, polymorphism, and crystal growth were examined. Additives can significantly affect the growth rate, acting as both accelerants and inhibitors. CTAB and benzoic acid had the ability to inhibit it; thioacetamide had the ability to promote it, while acetamide had no effect. Moreover, molecular simulations were adopted to propose mechanisms for the different regulating effects of the different additives. Also, the mechanism of growth regulation was proposed based on simulations and experiments. Additives affected crystal growth by impacting many kinds of interactions in the solution body and crystal surfaces.