Sensing and tuning microfiber chirality with nematic chirogyral effect

TitleSensing and tuning microfiber chirality with nematic chirogyral effect
Publication TypeJournal Article
Year of Publication2016
AuthorsČopar S a, Seč D a, Aguirre LE b, c Almeida PL b, e Dazza M d, f Ravnik M a, Godinho MH b, Pieranski P d, f Žumer S a
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
KeywordsChiral surface, Chirality, Condensed matter physics, Disclination rings, Elastic response, Mechanical control, Mechanical response, Microscopic levels, Optical micrographs, Physics, Translation symmetry

Microfibers with their elongated shape and translation symmetry can act as important components in various soft materials, notably for their mechanics on the microscopic level. Here we demonstrate the mechanical response of a micro-object to imposed chirality, in this case, the tilt of disclination rings in an achiral nematic medium caused by the chiral surface anchoring on an immersed microfiber. This coupling between chirality and mechanical response, used to demonstrate sensing of chirality of electrospun cellulose microfibers, is revealed in the optical micrographs due to anisotropy in the elastic response of the host medium. We provide an analytical explanation of the chirogyral effect supported with numerical simulations and perform an experiment to test the effect of the cell confinement and fiber size. We controllably twist the microfibers and demonstrate the response of the nematic medium. More generally the demonstrated study provides means for experimental discrimination of surface properties and allows mechanical control over the shape of disclination rings. © 2016 American Physical Society.