Spherulitic growth strategy: Improving the stability of metastable form and particle performances of m-aminobenzoic acid

In this study, we investigated the morphology modification of m-aminobenzoic acid (m-ABA) needle-like crystals using a spherulitic growth strategy to enhance their particle performance. Initially, the high sensitivity of solubility to temperature was effectively employed for screening solvents in cooling crystallization. Subsequently, additives with < 0.01% were successfully used to enhance the morphology of spherulites obtained in water. The underlying mechanism was elucidated through primary nucleation experiments. The spherulites prepared in isopropanol were optimized using single-factor analysis experiments, resulting in significant improvements in particle performance and crystal form stability compared to needle crystals. Additionally, a novel spherical shell spherulite grown in acetonitrile was presented and the morphological evolution mechanism was revealed through in-situ and ex-situ observations. Lastly, roughness and voidage were introduced as novel indicators to evaluate the morphology of the spherulites' outer surface and interior, respectively, and the relationship between the indicators was established.