Hydrodynamic instabilities in active cholesteric liquid crystals

Carl A. Whitfield, Tapan Chandra Adhyapak, Adriano Tiribocchi, Gareth P. Alexander, Davide Marenduzzo, Sriram Ramaswamy

    Research output: Contribution to journalArticlepeer-review


    We describe the basic properties and consequences of introducing active stresses, with principal direction along the local director, in cholesteric liquid crystals. The helical ground state is found to be linearly unstable to extensile stresses, without threshold in the limit of infinite system size, whereas contractile stresses are hydrodynamically screened by the cholesteric elasticity to give a finite threshold. This is confirmed numerically and the non-linear consequences of instability, in both extensile and contractile cases, are studied. We also consider the stresses associated to defects in the cholesteric pitch ($\lambda$ lines) and show how the geometry near to the defect generates threshold-less flows reminiscent of those for defects in active nematics. At large extensile activity $\lambda$ lines are spontaneously created and can form steady state patterns sustained by constant active flows.
    Original languageEnglish
    JournalEuropean Physical Journal E
    Issue number4
    Publication statusPublished - 1 Apr 2017


    • Soft Matter: Liquid crystals


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