Chirality Detection Using Nematic Liquid Crystal Droplets on Anisotropic Surfaces
Artikel i vetenskaplig tidskrift, 2016
Nematic liquid crystals (NLCs) form helical macroscopic structures through chiral induction when doped with chiral species. We describe a very simple, though highly sensitive method for determination of handedness and pitch of the induced twist in the case of very weak twisting powers of such chiral dopants. A tiny drop typically less than 10 nL-of the chiral doped NLC is placed on a plate promoting a uniform planar surface anchoring of the liquid crystal director. At the curved NLC air interface the anchoring is homeotropic and in the sessile droplets we get a locally twisted hybrid director structure with a disclination line extending across the droplet. The configuration of the disclination line (S-like or backwards S-like) reveals the sign of twisting power and extremely large pitch values in the range of 10 mm can easily be measured. We demonstrate the method using the standard NLC 4-cyano-4'-pentylbiphenyl (5CB), weakly doped with the chiral material 2-hydroxy-2-phenylacetic acid (mandelic acid).
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helical twisting power
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Författare
Per Rudquist
Chalmers, Mikroteknologi och nanovetenskap, Fotonik
C. F. Dietrich
Universität Stuttgart
A. G. Mark
Max-Planck-Gesellschaft
F. Giesselmann
Universität Stuttgart
Langmuir
07437463 (ISSN) 15205827 (eISSN)
Vol. 32 24 6140-6147Ämneskategorier
Materialkemi
DOI
10.1021/acs.langmuir.6b00382
PubMed
27244587