Impurity Effect of L-Valine on L-Alanine Crystal Growth

The effect of L-valine on the growth of the L-alanine (011) surface from solution crystallization is studied by combining single-crystal growth experiments and molecular simulation. For the first time, an unusual promotion effect of L-valine on L-alanine crystal growth, after the initial inhibition effect, is found when the impurity concentration is higher. Through molecular simulation, it is revealed that this unusual promotion effect is due to the close interaction between L-alanine and L-valine, which repels H2O around solute molecules and therefore eliminates the negative effect of H2O on surface diffusion of L-alanine.