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Effects of chemical and geometric microstructures on the crystallization of surface droplets during solvent exchange

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journal contribution
posted on 14.10.2021, 10:08 authored by Howon Choi, Zixiang Wei, Jae Bem You, Huaiyu YangHuaiyu Yang, Xuehua Zhang
In this work, we investigate the crystallization of droplets formed on micropatterned surfaces. By solvent exchange in a microchamber, a ternary solution consisting of a model compound β-alanine, water, and isopropanol was displaced by a flow of isopropanol. In the process, oiling-out droplets formed and crystallized. Our results showed that the shape and size of the crystals on surfaces with chemical micropatterns could be simply mediated by the flow conditions of solvent exchange. More uniform crystals formed on hydrophilic microdomains compared to hydrophobic microdomains or homogeneous surfaces. Varying flow rates or channel heights led to the formation of thin films with microholes, connected networks of crystals, or small diamond-shaped crystals. Physical microstructures (represented by microlenses) on the surface allowed the easy detachment of crystals from the surface. Beyond oiling-out crystallization, we demonstrated that the crystal formation of another solute dissolved in the droplets could be triggered by solvent exchange. The length of crystal fibers after the solvent-exchange process was shorter at a faster flow rate. This study may provide further understanding to effectively obtain the crystallization of surface droplets through the solvent-exchange approach.

Funding

Natural Science and Engineering Research Council of Canada (NSERC)

Future Energy Systems (Canada First Research Excellence Fund)

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Langmuir

Volume

37

Issue

17

Pages

5290 - 5298

Publisher

American Chemical Society

Version

AM (Accepted Manuscript)

Rights holder

© American Chemical Society

Publisher statement

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.langmuir.1c00354

Publication date

2021-04-23

Copyright date

2021

ISSN

0743-7463

eISSN

1520-5827

Language

en

Location

United States

Depositor

Dr Huaiyu Yang. Deposit date: 13 October 2021