title: Gel-induced selective crystallization of polymorphs.
abstract: Although nanoporous materials have been explored for controlling crystallization of polymorphs in recent years, polymorphism in confined environments is still poorly understood, particularly from a kinetic perspective, and the role of the local structure of the substrate has largely been neglected. Herein, we report the use of a novel material, polymer microgels with tunable microstructure, for controlling polymorph crystallization from solution and for investigating systematically the effects of nanoconfinement and interfacial interactions on polymorphic outcomes. We show that the polymer microgels can improve polymorph selectivity significantly. The polymorphic outcomes correlate strongly with the gel-induced nucleation kinetics and are very sensitive to both the polymer microstructure and the chemical composition. Further mechanistic investigations suggest that the nucleation-templating effect and the spatial confinement imposed by the polymer network may be central to achieving polymorph selectivity. We demonstrate polymer microgels as promising materials for controlling crystal polymorphism. Moreover, our results help advance the fundamental understanding of polymorph crystallization at complex interfaces, particularly in confined environments.
authors.affiliation: Novartis-MIT Center for Continuous Manufacturing and Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E19-502b, Cambridge, Massachusetts 02139, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Diao
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Whaley
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Helgeson
authors.forename: Mahlet A
authors.initials: MA
authors.lastname: Woldeyes
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Doyle
authors.forename: Allan S
authors.initials: AS
authors.lastname: Myerson
authors.forename: T Alan
authors.initials: TA
authors.lastname: Hatton
authors.forename: Bernhardt L
authors.initials: BL
authors.lastname: Trout
mesh_terms: D002220:Carbamazepine / Q000737:chemistry; D003460:Crystallization; D005782:Gels; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry
chemical_list: D005782:Gels; D011108:Polymers; D013876:Thiophenes; C098260:5-methyl-2-((2-nitrophenyl)amino)-3-thiophenecarbonitrile; D002220:Carbamazepine; D011092:Polyethylene Glycols