Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Elastomeric patterns probed by a nematic liquid crystalPublication . Trindade, A.C.; Almeida, A. P. C.; Canejo, João; Patricio, Pedro; Pieranski, Pawel; Godinho, Maria HelenaSoft Janus elastomers have two surfaces with diverse characteristics. In this work, by tuning the chemical composition and the surface roughness we were able to vary the wettability of thin films (thickness of 100-200 mu m) and spheres (diameters in the order of 200 mu m to 2 mm) and evidence the multifunction of the opposite sides. We also describe a simple and inexpensive method to reveal the wrinkled-labyrinthine patterns that appear in the Janus particles by means of a nematic liquid crystal (LC). LC contact angle measurements associated with the swelling and anchoring characteristics of the surfaces were used to image the Janus particles opening new platforms for sensor applications from flexible free-standing LCs containers.
- Sensing and tuning microfiber chirality with nematic chirogyral effectPublication . Copar, Simon; Sec, David; Aguirre, Luis E.; Almeida, Pedro L.; Dazza, Mallory; Ravnik, Miha; Godinho, Maria Helena; Pieranski, Pawel; Zumer, SlobodanMicrofibers 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.