CAREER: Probing Crystal Nucleation in Soft Confinement with Molecular Simulation

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Controlling crystal nucleation in liquids is important in applications related to pharmaceutical processing and designing materials. Crystal growth can be controlled to desired size, shape, and structure by fine tuning of the local environment in which nucleation takes place at the molecular level. The goal of this project is to understand crystal nucleation in liquids confined by soft hydrogel matrices. The confinement geometry and chemistry within the matrices may alter nucleation pathways and resulting crystallization. Advanced molecular simulation techniques will be used to discover the mechanisms by which soft hydrogel matrices influence crystal nucleation. The educational part of this project includes the development of a new short course and outreach activities to K-12 students in the Houston area.The overarching hypothesis will be tested by deploying rare-event molecular simulation techniques to address three specific aims: (1) to elucidate the mechanisms by which soft hydrogel matrices influence ice nucleation thermodynamics; (2) to identify the effects of soft confinement on the crystallization kinetics of water in hydrogels; (3) to probe the pathways for calcium carbonate precipitation in polymer brushes with tunable architectures. Free energy methods will be used to compute nucleation barriers and identify metastable intermediates, while path sampling algorithms will be employed to characterize crystallization kinetics and mechanisms. This combination of techniques will reveal the effects of matrix properties (density, surface chemistry, and morphology) on nucleation and thereby transform understanding of the physical processes controlling crystallization in soft matrices. A course focusing on reproducibility in science will be developed, The Art of Reproducible Science, and will be taught to graduate and undergraduate students at the University of Houston and broadly disseminated through online video tutorials. Outreach activities will be developed to provide K-12 students with opportunities to learn about research and STEM career paths through participation in the annual Lemelson-MIT JV InvenTeams program, GRADE summer program for women and underrepresented minorities, Texas Soft Matter Meeting, and Southwest Catalysis Society Meeting.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.