Isotropic-nematic phase transitions of lyotropic, two-dimensional liquid crystalline polymer solutions. Yim, K S, Fuller, G., Datko, A, & Eisenbach, C D Macromolecules, 34(20):6972–6977, 2001.
Isotropic-nematic phase transitions of lyotropic, two-dimensional liquid crystalline polymer solutions [link]Paper  abstract   bibtex   
Few studies of the isotropic-nematic phase transition temperature, T IN, in two dimensions have been reported experimentally in contrast to that of liquid crystalline polymers in three dimensions. The purpose of this paper is to examine molecular orientational hydrodynamics through studies of monolayer films at the air-water interface and to understand the phenomenon of the phase transition in two dimensions. UV absorption spectroscopy was used to determine molecular orientation in hairy-rod polymeric monolayers of poly(p-phenylene) sulfonic acid (PPPSH). A well-defined extensional flow is imposed in the monolayer to study the dynamics of flow-induced anisotropy. A solvent of stearic acid (SA) at moderate concentrations is added to the polymer solution to fluidize the film, and the effect of solvent on the isotropic-nematic transition is observed. Above T IN, complete relaxation of molecules is observed after flow cessation, while a nematic, ordered phase is obtained below T IN. Measurements of the surface rheological properties were also performed to further interrogate the phase transition.
@article{yim_isotropic-nematic_2001,
	Abstract = {Few studies of the isotropic-nematic phase transition temperature, T IN, in two dimensions have been reported experimentally in contrast to that of liquid crystalline polymers in three dimensions. The purpose of this paper is to examine molecular orientational hydrodynamics through studies of monolayer films at the air-water interface and to understand the phenomenon of the phase transition in two dimensions. UV absorption spectroscopy was used to determine molecular orientation in hairy-rod polymeric monolayers of poly(p-phenylene) sulfonic acid (PPPSH). A well-defined extensional flow is imposed in the monolayer to study the dynamics of flow-induced anisotropy. A solvent of stearic acid (SA) at moderate concentrations is added to the polymer solution to fluidize the film, and the effect of solvent on the isotropic-nematic transition is observed. Above T IN, complete relaxation of molecules is observed after flow cessation, while a nematic, ordered phase is obtained below T IN. Measurements of the surface rheological properties were also performed to further interrogate the phase transition.},
	Author = {Yim, K S and Fuller, G.G. and Datko, A and Eisenbach, C D},
	Journal = {Macromolecules},
	Number = {20},
	Pages = {6972--6977},
	Title = {Isotropic-nematic phase transitions of lyotropic, two-dimensional liquid crystalline polymer solutions},
	Url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0035949902&partnerID=40&md5=058464b3d34a34d99a9133f1588aa654},
	Volume = {34},
	Year = {2001},
	Bdsk-Url-1 = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0035949902&partnerID=40&md5=058464b3d34a34d99a9133f1588aa654}}

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