Gelation via Ion Exchange in Discotic Suspensions

Ya-Wen Chang, Andres F. Mejia, Zhengdong Cheng, Xiaojun Di, and Gregory B. McKenna

Phys. Rev. Lett. 108, 247802 – Published 15 June 2012

Abstract

The phase behavior of charged disk suspensions displays a strong dependence on ionic strengths, as the interplay between excluded volume and electrostatic interactions determines the formation of glasses, gels, and liquid crystal states. The various ions in natural soil or brine, however, could present additional effects, especially considering that most platelet structures bear a momentous ion-exchange capacity. Here we observed how ion exchange modulates and controls the interaction between individual disks and leads to unconventional phase transitions from isotropic gel to nematic gel and finally to nematic liquid crystals.

Received 10 March 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.247802

Authors & Affiliations

Ya-Wen Chang¹, Andres F. Mejia¹, Zhengdong Cheng^1,2,3,*, Xiaojun Di⁴, and Gregory B. McKenna⁴

¹Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, USA
²Material Science and Engineering Program, Texas A&M University, College Station, Texas 77843, USA
³Professional Program in Biotechnology, Texas A&M University, College Station, Texas 77843, USA
⁴Department of Chemical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, Texas 79409, USA