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Fast Surface Diffusion and Crystallization of Amorphous Griseofulvin.
Chengbin Huang1, Shigang Ruan2, Ting Cai3
1School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin 53705, United States.
The Journal of Physical Chemistry. B
|September 9, 2017
Summary
Griseofulvin (GSF) exhibits exceptionally fast surface diffusion, significantly exceeding bulk diffusion. This rapid molecular mobility in GSF glasses explains their fast crystallization rates, a key factor in material science.
Area of Science:
- Materials Science
- Physical Chemistry
- Amorphous Solids
Background:
- Molecular glasses are crucial in various applications.
- Understanding crystallization kinetics is vital for material stability.
- Griseofulvin (GSF) is known for rapid crystallization among molecular glasses.
Purpose of the Study:
- To investigate the surface diffusion mechanism in griseofulvin (GSF) molecular glasses.
- To correlate surface diffusion with the fast crystallization property of GSF.
- To elucidate the role of molecular structure and hydrogen bonding on surface diffusion.
Main Methods:
- Surface grating decay method was employed to measure surface diffusion.
- Comparison of surface diffusion data with other molecular glasses.
- Analysis of GSF's molecular structure and hydrogen bonding capabilities.
Main Results:
- Surface diffusion in amorphous GSF is extremely fast (10^8 times faster than bulk diffusion at Tg).
- GSF shows the second fastest surface diffusion among 13 molecular glasses studied.
- Surface diffusion correlates with crystal growth rate, indicating diffusion control.
Conclusions:
- Fast surface diffusion in GSF glasses drives their rapid crystallization.
- Polar groups do not inhibit surface diffusion if not involved in hydrogen bonding.
- Intermolecular hydrogen bonds significantly hinder surface diffusion, impacting crystallization.
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