| Liquid crystal elastomer(LCE)is a kind of responsive intelligent material which can be deformed under the stimulation of light source.It can be introduced into the micro-infusion valve device of environmental inspection by using this characteristic.It can control the fluid transportation in extreme environment,Instead of the previous power consumption of mechanical parts,so as to achieve the purpose of saving energy.In this paper,prepared photothermal response and azobenzene photoresponsive two kinds of light-responsive LCE films,and were compared by photoelectric deformation properties and nonlinear optical characteristics,Among them,azobenzene photoresponsive LCE was more suitable for micro-infusion valve.On the basis of the above,the structure and properties of the azobenzene photoresponsive LCE films were analyzed by UV-Vis absorption spectroscopy,transmission electron microscopy,polarizing microscope,differential scanning caloriimetry,polarized light source and mechanical testing machine.At last design and prepared the micro-infusion valve device.The main research contents are as follows:(1)The phototherimal response of the black LCE film and the Nano-Ag/LCE composite film doped with Ag nanoparticles(Nano-Ag)were prepared by two-step cross-linking method.The shrinkage rates of the two films were 20%and 27%,respectively,and the response rates were 15 s and 10 s,respectively.Photothermal response Nano-Ag/LCE composite films can improve the photothermal conversion rate due to the incorporation of Ag nanoparticles,and the response speed and deformation amplitude are obviously improved compared with the black photothermal responsive LCE films,and have excellent nonlinear optical characteristics.(2)In the synthesis of crosslinking agent 1,4-bis[4-(9-acryloyloxy)n-nonyloxy]benzoyloxy-2-methylbenzene(C9A)and 4,4'-bis[11-(acryloyloxy)nonanyloxy]azobenzene(DA11AB)was prepared by one-step cross-linking method.Compared with the photothermal response Nano-Ag/LCE composite film,although there is no obvious nonlinear optical characteristics,but its optical response speed was extremely fast at 5s to about 45%deformation amplitude,the maximum bending angle of about 90°.So that the azobenzene photoresponsive LCE film is more suitable for reference into the micro-infusion valve.(3)The azobenzene group is a photoresponsive group,and its content has some influence on the photo-bending properties of the films.The effects of different azobenzene contents on the properties of LCE films were investigated.The results show that the LCE film with azobenzene content of 20%is the best,the order is the highest,5s can reach the maximum bending angle of about 90°,the maximum bending stress is about 0.59 Mpa under the 10500 lx light intensity.(4)Due to azobenzene light response LCE film in the actual operation was easy to break and after close the light source the bending recovery performance is slow.In order to improve the durability and photorefractive recovery of LCE films,the CNT-Film/LCE composite films were prepared by CNT-film as the base layer and azobenzene photoresponsive LCE films.The effects of azobenzene content on the properties of CNT-Film/LCE composite films were investigated by photometric properties and photorefractive stress testing The experimental results showed that CNT-film/LCE composite films with 20%azobenzene content were 4s to reach the maximum bending deformation of about 90°,and within 5s can automatically return to the initial state,the maximum bending stress is about 0.22 Mpa under the 10500 lx light intensity.The performance of CNT-Film/LCE composite film with 20%azobenzene content is the best,and it is most suitable for use in micro-infusion valve.(5)A simple concept device of micro-infusion valve was designed and fabricated using CNT-Film/LCE composite film with 20%azobenzene content,and simulated the operation mode of microvalve simple concept device.To further improve its light bending stress in water,It can be applied to the environmental detection of micro fluid transport for polluted water. |
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