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Optical properties of colloidal suspensions and thin films based on natural polymers and lanthanides

Abstract

The main focus of this project concerns the study of composites based on natural polymers (Bacterial celulose and silk fibroin) and lanthanides. Bacterial Cellulose, produced at the surface of culture médium of the Gluconacetobacter xylinus, will be used for the production of nanocellulose which in aqueous suspensions may self-assemble to the quiral nematic phases. The liquid crystalline suspensions will be characterized aiming the control of the cholesteric pitch and therefore of the observed pseudo-color. This films will be deposited on glass substrates by using "doctor-blade" techniques leading to pigmentless colored films. Nanostructured films based on silk fibroin will be also prepared and the optical properties studied as a function of the self-assembly properties. Colloidal suspensions of both natural polymers will be prepared containing lanthanide ions. Light emission properties in the visible and infrared will be characterized together with the pseduo-colors due to the self-assembly. 2 undergraduate, 2 graduate and one PhD are expected to participate in this Project. (AU)