The Preparation And Characterization Of Cellulose Nanocrystals-based Helix Assembler Optical Materials

In nature,many living creature can produce rainbow color.Among the structural color,polarized structural color is a special structural color,With the research development of biological polarized structural coloring mechanism,researchers have successfully developed series of novel bio-inspired optical materials with fine structure in recent years.Nowadays,researchers have found that CNCs have nano-sized cellulose structure and can ordered self-assembly controllably,various new optical materials can be developed based on the its helix self-assembled properties.In this study,we targeted the study of CNCs,and have mimicked the shell structure of gold scarab beetle in the nature and designed a new sandwiched optical structure.Uniaxial nylon 6 thin film with special thickness was chosen to be the middle layer which have the effect of phase retardation,and the final nanocomposite film can have the peculiarity of hyper-reflection.A bio-inspired hyper-reflection flexible composite film was prepared by using evaporation-induced self-assembly technology.To make the final nanocomposite thin film be flexible,hydrotropic polymer poly(ethylene glycol)diacrylate was chosen to be dopant,UV photo polymerization technology was used to form polymer network.The reflectance of nanocomposite film can be 79%,which demonstrated the excellent hyper-reflection property of film.Moreover,based on the tunability of order helix structure of cellulose nanocrystals and the hydroscopicity of Polyethylene glycol acrylate,the humidity-responsive behavior of nanocomposite materials has been studied.Results showed that the film can happen fast response under the humidity condition,deformation and discoloration are also happened at the same time.There are no break and stratification phenomenon occurred after 20 times cycle test which demonstrated that the film has good reversible resilience.In addition,the shear Angle can result in the difference deformation of thin film under a humidity condition,when the?=0 or ?/2,thin film was bent;while the film showed spiral twist shape when the ?=?/4,and a series of potential applications have been presented by triggering the nanocomposite film with steam.We believed that this work lay the foundation for the research of hyper-reflection nanocomposite,the material can be used in some important areas,such as energy saving,environment protecting,filter,environmental sensor,special anti-counterfeiting and so on.