CONCLUSION
In summary, this work demonstrated that directional freeze-casting of
liquid crystalline CNCs is an ideal method for preparation of a novel
anisotropic aerogel that features hierarchical structures and oriented
long-range ordering. During the freeze-casting process, the isotropic
CNC suspension can be aligned and trapped by the elongation flow of ice
crystals, whose orientations can be preserved by sublimation of the ice
template. In the case of anisotropic liquid CNC crystals, CNCs assemble
with the assistance of ice crystals, with their liquid crystalline
ordering then transferred into the subsequent aerogel. These new
bio-based aerogels exhibit oriented ordering, anisotropic optical
properties and high porosity, that may find applications in
high-performance insulators, tissue engineering, catalyst supports and
adsorption media.
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