Chiral organosilica particles of size ~200 nm were synthesized from an enantio-pure multi-armed chiral D-maltose organosilane precursor in the absence of co-condensation with an achiral monomer. Two distinct experiments were performed to demonstrate the particles’ ability to induce conformational deracemization of a host liquid crystal. The first involves an electric field-induced tilt of the liquid crystal director in the deracemized smectic-A phase. The other involves domain wall curvature separating left- and right-handed liquid crystal helical pitch domains imposed by the cells’ substrates. The results demonstrate unequivocally that enantio-pure organosilica nanoparticles can be synthesized and can induce chirality in a host.
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Chiral polymeric nanocapsules and their use for conformational deracemization of liquid crystals
We present the first preparation and properties of chiral nanocapsules. The chiral shell, a polyurea derivative, was obtained by interfacial emulsion polymerization of L-lysine with polymethylene polyphenyl isocyanate. The chirality of these nanocapsules was manifested by its ability to induce conformational deracemization of liquid crystal. This induced chirality was measured using the “Raynes experiment”, in which the cell’s boundary conditions impose a ±90o rotation of the liquid crystal director from one surface to the other. Both left and right-handed director twist domains appear on cooling from the isotropic to the nematic phase. Owing to the weak induced chirality of the liquid crystal, one sense of director rotation is energetically more favorable and its domain size expands, resulting in curvature of the domain walls. The curvature was measured as a function of capsule concentration, and serves as a metric of the induction of chirality in the surrounding liquid crystal.
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- Award ID(s):
- 1505389
- NSF-PAR ID:
- 10067923
- Date Published:
- Journal Name:
- Journal of physical chemistry. C
- Volume:
- 122
- ISSN:
- 1932-7447
- Page Range / eLocation ID:
- 17936-17941
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/http://dx.doi.org/10.1021/acs.jpcc.8b06005
