Controlling polymorphism by crystallization on self-assembled multilayers

In this paper, we present a new approach based on crystallization onto self-assembled multilayers (SAMs) for the control of polymorphism. To demonstrate our approach, we studied the crystallization of L-glutamic acid on a self-assembled multilayer of a phenyalanine derivative. It is shown that crystallization of L-glutamic acid on SAMs resulted in stabilization of the metastable alpha-form of L-glutamic acid. Additionally, crystallization onto SAMs led to crystal growth with preferential orientation along the < 111 > crystal direction. The possibility of using SAM surfaces to stabilize thermodynamically metastable structures as demonstrated in this work offers a powerful tool in the development of processes in polymorphic systems.