The Research Of Photo/Thermo-Responsive Fluorescent Liquid Crystal Elastomers For Information Storage

In recent years,stimuli-responsive smart materials whose physical or chemical properties change under external stimuli have attracted more and more attention,because they have broad application prospects in the fields of information display,anti-counterfeiting,sensors,and bionic devices.α-Cyanodiarylethene-based fluorescent molecules with high luminescence efficiency and sensitive stimuli-responsiveness exhibit unique advantages in information storage and encryption applications.However,information storage systems based on tunable fluorescence are relatively simple in function,and it is of great significance to develop information storage systems with multiple storage modes and encryption strategies.Liquid crystal elastomers(LCEs)exhibit excellent mechanical properties,sensitive stimuli responsiveness,and flexible deformability,and its reversible,complex,and programmable deformation provide the possibility for information display and protection.In this study,from the perspective of developing multifunctional information storage and encryption materials,fluorescent LCEs with various response behaviors were designed and constructed by combining photo-responsive α-cyanodiarylethene-based fluorescent molecules with liquid crystal matrix.Subsequently,we investigated the phototunable fluorescence and programmable deformations of fluorescent LCEs,and explored their potential applications in information storage,displays,and multi-modal information encryption.The main researches are as follows:1.A novel fluorescent LCE for multi-dimensional and multi-stage information storage is developed by synergistic utilization of phototunable fluorescence and photoprogrammable shapes.First,a novelα-cyanodiarylethene-based fluorescent molecule DPPTA was designed and synthesized,and the monoacrylate fluorescent hydrogen-bonded(H-bonded)complex DPPTA-AHBA was prepared by hydrogen bond assembly.The photo-responsive mechanism and phototunable behavior of DPPTA and DPPTA-AHBA were studied.Subsequently,the fluorescent LCE films were fabricated by incorporating the fluorescent H-bonded complex DPPTA-AHBA and the azobenzene derivative A6 A into the LC matrix through photopolymerization.Under the alternating irradiation of 365 nm UV light and450 nm blue light,the fluorescent information can be written and erased on the fluorescent LCE films for many times due to the reversible Z/E isomerization of DPPTA-AHBA.The shape of the fluorescent LCE film is programmed by selective irradiation of UV light,which can trigger various deformations and realize 3D information storage upon heating.Finally,using the synergistic change of fluorescence intensity and shape under 365 nm UV light,the encrypted information is written on the fluorescent LCE film,which is gradually decrypted under UV light and heating,thus realizing multi-stage and multi-dimensional information storage and encryption.2.A reconfigurable fluorescent LCE with dynamic covalent bonds was designed and developed for integrated visual and haptic information storage and display.Firstly,α-cyanodiarylethene-based fluorescent acceptor BPTA was synthesized,and further assembled with proton donor AHBA to prepare diacrylate fluorescent H-bonded complex BPTA-AHBA.Subsequently,the fluorescent LCE films with dynamic covalent bonds were prepared in two steps of amine-acrylate aza-Michael addition reaction and photopolymerization.Due to the photoisomerization of BPTA-AHBA and the catalyst-free transesterification reaction activated at high temperature,the fluorescent LCE film exhibits phototunable fluorescence,thermally reconfigurable shape,and shape memory ability.Based on the above properties,the fluorescent LCE film can store a variety of information such as visible information,single-encrypted information and double-encrypted information.Furthermore,by combining fluorescence information based on photoswitchable fluorescence and Braille information based on thermally reconfigurable shapes,information readable by all users,including the visually impaired,was recorded on the fluorescent LCE films.3.A novel self-healable fluorescent LCE was designed and developed for information storage and display inspired by movable type printing.First,a polymerizable α-cyanodiarylethene-based fluorescent molecule CPTHA was designed and synthesized,and the photoresponsive properties of CPTHA in solution were studied.The photoswitch CPTHA can undergo reversible Z/E isomerization under the irradiation of 450 nm blue light and 365 nm UV light,and exhibit excellent photoresponsive performance and good fatigue resistance.Subsequently,novel fluorescent LCEs were prepared by heating through a two-stage amine-acrylate aza-Michael addition reaction.The monodomain fluorescent LCE films can be easily obtained by mechanical programming during the cross-linking stage,and their thermally responsive deformation and phototunable fluorescence properties were investigated.By introducing boronic ester-based dynamic covalent bonds,the fluorescent LCE system exhibits excellent reconfigurable shape and self-healing ability.Combining photo-responsive fluorescence with self-healing properties,an information storage method inspired by movable type printing is demonstrated,which realizes the free combination of information,storage and display of large-area information,and prolongs the service life of information storage materials.In summary,a series of fluorescent LCEs with different functions have been developed and their applications in the field of information storage and encryption have been studied.This study provides a new idea for the development of novel polymer storage materials,and broadens the application prospects of LCEs in information storage,encryption and anti-counterfeiting.