Liquid Crystalline Nanoparticles via semiflexible polymer ligands
Liquid crystallinity is a way to spontaneously create ordered nanoparticle arrays on a large scale for optical, electronic or magnetic applications
Anisotropic nanoparticles, like carbon nanotubes, gold nanorods and graphene, can form lyotropic LC phases in concentrated solutions in the presence of surfactants or charge based colloidal stabilizers.
Shape anisotropy (rod or disc-shaped) should result in anisotropic LC phases - nematic or smectic in the case of rods and columnar LC phases for discotic molecules. Spherical (i.e. isotropic) particles, such as micelles of surfactants, should form cubic phases.
We recently showed that attaching semiflexible polymer chains to 4nm spherical nanoparticles induces lyotropic liquid crystallinity in concentrated solutions, similar to biological molecules like DNA or phospholipids.
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Rigid, helical polymer, extensively studied
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Persistence length ~ 20 nm (chloroform)
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~ 40 nm (toluene or hexane)
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Lyotropic nematic phases in a range of organic solvents
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Chiral variants
The nanoparticles with PHIC ligands spontaneously
form linear arrays when deposited on a surface.
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"Lyotropic Nematic Phases of Isotropic Nanoparticles via Semiflexible Polymer Ligands."
Wong, Jessie, Violeta Toader, and Linda Reven.
Macromolecular Rapid Communications 44.8 (2023): 2200951.
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Nanoparticles with polypeptide ligands: Chiral plasmonics
Now we are extending this approach to synthetic polypeptides that display both lyotropic (concentration dependent) and thermotropic (temperature dependent) chiral liquid crystallinity and to gold nanoparticles.
Liquid crystals have been used as a template to produce helical gold nanoparticle assemblies but our idea is to make gold nanoparticles that spontaneously form helices.
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Such assemblies should display chiral plasmonics.
Lewandowski et al. Advanced Materials 32, (2020): 1905591.