Preparation And Application Of Flexible Polymer Photonic Reflective Films

Polymer photonic reflective films based on cholesteric helical superstructures have great application potential in the fields of optical functional films and anti-counterfeiting in recent years due to their characteristics of selective reflection and circular dichroism.However,there is still a lack of systematic research on how to prepare polymer cholesteric photonic films with high reflectivity and good adhesion to substrates through simple processes.In this paper,the preparation process optimization based on ultraviolet(UV)photopolymerization is studied.On this basis,polymer photonic films and their composites with broadband reflection,total reflection and circularly polarized fluorescence characteristics are prepared.The basic results are as follows:(1)Polymer photonic films have been successfully prepared on polyester(PET)flexible substrates by UV polymerization and doctor-blade coating under room temperature and air conditions by selecting suitable solvents.The obtained flexible photonic film has uniform surface,good orientation and strong adhesion with the substrate.Furthermore,by changing the content of chiral dopants in nem atic liquid crystals,polymer photonic films reflecting blue,green and red colors were prepared.(2)Polymer thin films with 400 nm to 630 nm reflecting band were successfully prepared on PET substrate by using lamination coating process,and polymer photonic films with broadband characteristics were obtained.Using the phase retardation effect of nematic liquid crystal,a three-layer photonic film composed of cholesteric liquid crystal,nematic liquid crystal and cholesteric liquid crystal was prepared on PET substrate.The measured reflectivity was close to 80%,and the preparation of polymer photonic film with total reflection characteristics was realized.(3)The prepared polymer photonic film and cholesteric liquid crystal material with circularly polarized fluorescence property are combined together,and the asymmetry factor of the circularly polarized luminescence is increased based on the circular dichroism and selective reflection property of the polymer photonic film.In this thesis,the preparation technology of cholesteric polymer photonic films with good comprehensive properties has been systematically studied,and prepared polymer photonic films and composite materials with special optical properties,such as broadband reflection,total reflection and circularly polarized fluorescence properties,were realized.This paves a way for the utilization of this kind of materials in special optical films and anti-counterfeiting fields.