Chiral nanomaterials possess unique electronic, magnetic,
and optical
properties that are relevant to a wide range of applications including
photocatalysis, chiral photonics, and biosensing. A simple, bottom-up
method to create chiral, inorganic structures is introduced that involves
the co-assembly of TiO2nanorods with cellulose nanocrystals
(CNCs) in water. To guide experimental efforts, a phase diagram was
constructed to describe how phase behavior depends on the CNCs/TiO2/H2O composition. A lyotropic cholesteric mesophase
was observed to extend over a wide composition range as high as 50
wt % TiO2nanorods, far exceeding other examples of inorganic
nanorods/CNCs co-assembly. Such a high loading enables the fabrication
of inorganic, free-standing chiral films through removal of water
and calcination. Distinct from the traditional templating method using
CNCs, this new approach separates sol–gel synthesis from particle
self-assembly using low-cost nanorods.