Reference : Isotropic–isotropic phase separation and spinodal decomposition in liquid crystal–sol...

	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Chemistry Physical, chemical, mathematical & earth Sciences : Physics Physical, chemical, mathematical & earth Sciences : Multidisciplinary, general & others Engineering, computing & technology : Chemical engineering Engineering, computing & technology : Materials science & engineering Engineering, computing & technology : Multidisciplinary, general & others
	Focus Areas :	Physics and Materials Science
	To cite this reference:	http://hdl.handle.net/10993/40182

Title :	Isotropic–isotropic phase separation and spinodal decomposition in liquid crystal–solvent mixtures
Language :	English
Author, co-author :	Reyes, Catherine [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
	Baller, Jörg [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
	Araki, Takeaki [Kyoto University > Department of Physics]
	Lagerwall, Jan [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Publication date :	14-Jun-2019
Journal title :	Soft Matter
Publisher :	Royal Society of Chemistry
Volume :	15
Pages :	6044-6054
Peer reviewed :	Yes (verified by ORBilu)
Audience :	International
ISSN :	1744-683X
e-ISSN :	1744-6848
City :	Cambridge
Country :	United Kingdom
Keywords :	[en] liquid crystal ; 5CB ; phase separation ; ethanol ; binary mixtures ; water ; phase diagram ; free energy ; concentration gradient ; polarized optical microscopy ; DSC ; numerical simulation
Abstract :	[en] Phase separation in mixtures forming liquid crystal (LC) phases is an important yet under- appreciated phenomenon that can drastically influence the behaviour of a multi-component LC. Here we demonstrate, using polarising microscopy with active cooling as well as differential scanning calorimetry, that the phase diagram for mixtures of the LC-forming compound 4’-n- pentylbiphenyl-4-carbonitrile (5CB) with ethanol is surprisingly complex. Binary mixtures reveal a broad miscibility gap that leads to phase separation between two distinct isotropic phases via spinodal decomposition or nucleation and growth. On further cooling the nematic phase enters on the 5CB-rich side, adding to the complexity. Significantly, water contamination dramatically raises the temperature range of the miscibility gap, bringing up the critical temperature for spinodal de- composition from ∼ 2◦C for the anhydrous case to > 50◦C if just 3 vol.% water is added to the ethanol. We support the experiments with a theoretical treatment that qualitatively reproduces the phase diagrams as well as the transition dynamics, with and without water. Our study highlights the impact of phase separation in LC-forming mixtures, spanning from equilibrium coexistence of multiple liquid phases to non-equilibrium effects due to persistent spatial concentration gradients.
Target :	Researchers ; Professionals ; Students ; General public ; Others
Permalink :	http://hdl.handle.net/10993/40182
DOI :	10.1039/C9SM00921C
Other URL :	https://pubs.rsc.org/en/content/articlelanding/2019/SM/C9SM00921C#!divAbstract
Framework Programme / European Project :	H2020 ; 648763 - INTERACT - Intelligent Non-woven Textiles and Elastomeric Responsive materials by Advancing liquid Crystal Technology

	File(s) associated to this reference
	Fulltext file(s): File Commentary Version Size Access Open access 5CB-final-postprint.pdf Embargo ends June 2020; email corresponding authors for a copy Publisher postprint 6.91 MB View/Open Additional material(s): File Commentary Size Access Open access Supplementary Data for Experiments.pdf Supplementary Data for Experiments in Main Paper 8.11 MB View/Open Open access SM1.mp4 Supplementary Movie #1 5.35 MB View/Open Open access SM2.mp4 Supplementary Movie #2 2.63 MB View/Open Open access SM3.mp4 Supplementary Movie #3 3.44 MB View/Open Open access SM4.mp4 Supplementary Movie #4 2.79 MB View/Open Open access SM5.mp4 Supplementary Movie #5 4.83 MB View/Open Open access SM6.mp4 Supplementary Movie #6 3 MB View/Open Open access SM7.mp4 Supplementary Movie #7 3.89 MB View/Open Open access SM8.mp4 Supplementary Movie #8 2.18 MB View/Open

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