Controllable crystallization of urea crystal face (0 0 1) by molecular simulation

Crystal regulation including crystal habit and size regulation is of considerable significance in chemical and pharmaceutical industry. Here urea is used as a typical crystal model, because crystal formation of urea is simple and its traditional crystallization is uncontrollable. Therefore, we adopted molecular dynamics simulation to study the crystal-solution interface during the urea crystal growth. And the regulation mechanism of additive on urea crystal growth was further revealed by analyzing the adsorption energy, density profile, diffusion coefficient, number of contact and H-bond interaction of four additives (trehalose, sorbitol, glucose, and l-lysine) on the crystal face (0 0 1). The results indicated that to some extent, those additives can do inhibit the growth of urea crystal face (0 0 1) at 1 atm and 290 K. The more negative adsorption energy of the additive on crystal face (0 0 1) can lead to the better inhibitive efficiency. And the trehalose is one of the best inhibitors for the growth of crystal face (0 0 1). The type and number of the polar group carried by additives determine their regulation capability.