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cellulose free-standing films
iridescence
liquid-crystalline polymer solutions
nanocrystalline cellulose rods
structural colors
Cellulosic films
Free-standing thin films
Freestanding films
Mechanical characteristics
Nanocrystalline cellulose
Shear direction
Structural color
Surface feature
Cellulose
Cellulose derivatives
Crystalline materials
Liquid crystal polymers
Liquids
Modulation
Optical properties
Surfaces
Cellulose films
Liquid Crystals
Polymers
Thin Films
Abstract:
Shear transparent cellulose free-standing thin films can develop iridescence similar to that found in petals of the tulip "Queen of the Night." The iridescence of the film arises from the modulation of the surface into bands periodically spread perpendicular to the shear direction. Small amounts of nanocrystalline cellulose (NCC) rods in the precursor liquid-crystalline solutions do not disturb the optical properties of the solutions but enhance the mechanical characteristics of the films and affects their iridescence. Smaller bands periodicity, not affected by the NCC rods, slightly deviated from the shear direction is also observed. NCCs are crucial to tune and understand the film's surface features formation. Our findings could lead to new materials for application in soft reflective screens and devices. Shear transparent free-standing cellulosic films, prepared from liquid-crystalline solutions, can develop iridescence arising from the modulation of the surface of the films, similar to that found in the petals of the tulip variety "Queen of the Night." Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
