科研之友
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摘要
Nucleation kinetics of small-molecule organics can be directed by heterogeneous surfaces imprinted with angular nanopatterns. In this work, we utilized biocompatible polymer thin films to enhance the nucleation rates of paracetamol (APAP). We, found that flat polymer films without nano imprinting enaljled crystallization of APAP two times faster than bulk crystallization. Nanoimprinting of polymer films led to further enhancement of the nucleation rates. Polymer films imprinted with a nanopattern containing 40 angles were the most effective.and enabled crystallization of APAP four times faster than bulk crystallization and two units faster- Than crystallization with flat polymer films. The films imprinted with the nanopatterns,containing 60, 65, 80, or 90 angles were more effective in enhancing crystallization of APAP than the flat films but less effective compared to the 40 nanopattern: We. also performed molecular-dynamics simulations and an analysis of the hydrogen bOnding between crystal faces and the polyther surface. The results suggest that the 40 pattern, the smallest angle nanopattern, targets the (001) and (on) faces (intrinsic angle of 34) due to the strong interaction of these crystal faces with the polymer. The computational results are supported by crystallographic studies 'and atomic force microscopy images of a nanocrystal growing, in the corners of the nanopatterns. Our findings indicate.-y\iays to rationally design the geometry of heterogeneous surfaces to enhance the nucleation of sniall.mOlecule organics. Moreover; considering that the only required input for thiS design is the:chemical structure of theycilyMer and the chemical and crystal structure of the crystallizing solute, we expect that our method IS.applicable to a wide range of Crystallization processes.
- 出版日期2017-6
