title: Sensing and tuning microfiber chirality with nematic chirogyral effect.
abstract: 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.
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
authors.forename: Simon
authors.initials: S
authors.lastname: Čopar
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
authors.forename: David
authors.initials: D
authors.lastname: Seč
authors.affiliation: CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Aguirre
authors.affiliation: CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.|Área Departamental de Física, Instituto Superior de Engenharia de Lisboa, ISEL, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, Portugal.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Almeida
authors.affiliation: Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, Bât. 510, 91405 Orsay, France.|École normale supérieure de Cachan, 61, avenue du Président Wilson, 94235 Cachan, France.
authors.forename: Mallory
authors.initials: M
authors.lastname: Dazza
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.|J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: Miha
authors.initials: M
authors.lastname: Ravnik
authors.affiliation: CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
authors.forename: Maria H
authors.initials: MH
authors.lastname: Godinho
authors.affiliation: Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, Bât. 510, 91405 Orsay, France.
authors.forename: Pawel
authors.initials: P
authors.lastname: Pieranski
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.|J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: Slobodan
authors.initials: S
authors.lastname: Žumer