Direct Observation of Liquid Crystal Droplet Configurational Transitions using Optical Tweezers

Jake Shechter, Noe Atzin, Ali Mozaffari, Rui Zhang, Ye Zhou, Benjamin Strain, Linda M. Oster, Juan J. de Pablo, Jennifer L. Ross

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Liquid crystals (LCs) are easily influenced by external interactions, particularly at interfaces. When rod-like LC molecules are confined to spherical droplets, they experience a competition between interfacial tension and elastic deformations. The configuration of LCs inside a droplet can be controlled using surfactants that influence the interfacial orientation of the LC molecules in the oil-phase of an oil in water emulsion. Here, we used the surfactant sodium dodecyl sulfate (SDS) to manipulate the orientation of 5CB molecules in a polydisperse emulsion and examined the configuration of the droplets as a function of SDS concentration. We triggered pronounced morphological transitions by altering the SDS concentration while observing an individual LC droplet held in place using an optical tweezer. We compared the experimental configuration changes to predictions from simulations. We observed a hysteresis in the SDS concentration that induced the morphological transition from radial to bipolar and back as well as a fluctuations in the configuration during the transition.

Original languageEnglish (US)
Pages (from-to)7074-7082
Number of pages9
JournalLangmuir : the ACS journal of surfaces and colloids
Volume36
Issue number25
DOIs
StatePublished - Jun 30 2020

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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