1 research outputs found
Composite Films with Ordered Carbon Nanotubes and Cellulose Nanocrystals
Composite films with
oxidized carbon nanotubes (o-CNTs) incorporated
in the chiral nematic liquid crystals (CNLCs) formed by cellulose
nanocrystals (CNCs) were fabricated for the first time. Induced by
solvent evaporation, the isotropic aqueous dispersion containing o-CNTs
and CNCs gradually forms lyotropic CNLCs, and the framework of the
CNLCs can be retained in the final solid films, confirmed by polarized
optical microscopy observations and scanning electron microscopy observations.
During this evaporation-induced self-assembly process, the predispersed
o-CNTs were spontaneously integrated in the liquid crystal matrix.
It is found that the incorporation of a trace amount of o-CNTs (∼1.5
wt %) can induce obvious structural changes of the films. The reflection
spectrum shifts to higher wavelengths with increasing content of o-CNTs,
resulting in a continuous increase of the helical pitch of the CNLC
phase. Confined in the liquid crystal matrix, the randomly oriented
o-CNTs in the aqueous dispersion are forced to adopt a higher degree
of order. This ordered arrangement of o-CNTs combined with the intrinsic
anisotropy of the CNLCs impart the composite film anisotropic conductivity
as proved by the electrical resistance measurements. This new type of CNTs/CNCs composites
could find applications in various fields such as sensors and photoelectronics