Control Over Phase Separation and Nucleation Using a Optical-Tweezing Potential

Wynne, K. and Walton, F. (2018) Control Over Phase Separation and Nucleation Using a Optical-Tweezing Potential. In: SPIE Nanoscience + Engineering 2018, San Diego, CA, USA, 19-23 Aug 2018, 107230O. ISBN 9781510620179 (doi: 10.1117/12.2324119)

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Abstract

Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a black art. Although there are now numerous examples of control using laser-induced nucleation, a physical understanding is absent and preventing progress. We will show that concentration fluctuations in the neighborhood of a liquid-liquid critical point can be harnessed by an optical-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in liquid mixtures using a low-power laser diode confirm the effect. Phase separation and nucleation through an optical-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

Item Type:Conference Proceedings
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Walton, Mr Finlay and Wynne, Professor Klaas
Authors: Wynne, K., and Walton, F.
College/School:College of Science and Engineering > School of Chemistry
College of Science and Engineering > School of Engineering > Systems Power and Energy
ISBN:9781510620179
Copyright Holders:Copyright © 2018 SPIE
First Published:First published in Proceedings of SPIE 10723: 107230O
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
571341Liquid-liquid transitions in molecular liquids: from supramolecular structure to phase separationKlaas WynneEngineering and Physical Sciences Research Council (EPSRC)EP/J004790/1CHEM - CHEMISTRY
582891The structure and dynamics of water confined in nanoscale pools: the dynamic crossoverKlaas WynneEngineering and Physical Sciences Research Council (EPSRC)EP/J009733/1CHEM - CHEMISTRY
697461Mapping and controlling nucleationKlaas WynneEngineering and Physical Sciences Research Council (EPSRC)EP/N007417/1CHEM - CHEMISTRY