Polymorphism stabilization by crystal adsorption on a self-assembled monolayer

The control over crystal polymorphism is a well-established subject in crystallization and materials chemistry. In recent years, self-assembled monolayers (SAMs) with different functionalized groups have been used as a new chemical approach to control crystal nucleation and polymorphism. In this paper, we focus on a study of the different mechanisms involved in polymorphism control by crystallization onto SAMs. We study the crystallization of l-glutamic acid on SAMs with various functionalized end groups: R-OH, R-CH₃ and R-COOH. Furthermore, in this work we select crystallization conditions in which we can identify different mechanisms of polymorphism stabilization and show that functionalized SAMs can be used to stabilize crystal polymorphism by means of crystal adsorption from the crystallization solution onto SAMs, and not merely by nucleation and crystal growth onto the SAMs.