Isotropic-nematic phase transition of polydisperse clay rods

Phillip Woolston, Jeroen S Van Duijneveldt

Research output: Contribution to journalArticle (Academic Journal)peer-review

9 Citations (Scopus)
331 Downloads (Pure)

Abstract

Rod-like colloidal particles are known to display an isotropic-nematic phase transition on increase of concentration, as predicted already by Onsager. Both natural clay particles and synthetic rods tend to be polydisperse, however, and the question arises how to allow for this in comparing experimental observations with theory. Experimental data for a wide range of samples (both from the literature and the new results) have been collated, with aspect ratios ranging from 14 to 35. As a characteristic, the concentration is taken where half of the sample volume is nematic. Experimental data agree well with predictions for monodisperse finite aspect ratio rods. However, compared to these predictions, the width of the transition (taken as the ratio of isotropic and nematic limiting concentrations) is noticeably broadened. Still, in most cases, the transition can be characterised by a linear increase of the nematic phase volume with sample concentration. The transition width is in broad agreement with theoretical predictions for infinitely thin rods.

Original languageEnglish
Article number184901
Number of pages5
JournalJournal of Chemical Physics
Volume142
DOIs
Publication statusPublished - 11 May 2015

Bibliographical note

Date of Accptance: 28/04/2015

Keywords

  • Onsager
  • Nematic
  • Clay rods
  • Polydispersity;
  • Aspect Ratio

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