| As a sort of wide material sources, excellent repetition and tunable structure,polysaccharide compounds suit for many different demands. Polysaccharide molecule chaincontains a lot of functional groups, such as hydroxyl, amino, carboxyl, so in this paper twokinds of spiropyran monomers were introduced to natural polysaccharide compound system,to design and synthesis of natural macromolecular materials with photo-responsivecharacteristics, given its unique optical properties. This topic results provided theoreticalsupport for the development of new photosensitive material, anti-counterfeiting materials,sensing materials, and light controlled release materials. The main content and the results ofthis paper are as following:According to the structure of polysaccharide compounds, two kinds of light-responsivemonomers (SPCOOH and SPMA) were designed and prepared. For spiropyran monomers,their photochromic properties were affected by substituent groups and solvent. SPMAextinction kinetic dynamics in different solvents were also analyzed. The results have shownthat the closing reaction of SPMA was a first order reaction, and the reaction rate indichloromethane, methylbenzene and acetone reduced in turn.Amphiphilic polymer with hydrophobic spiropyran and starch was synthesized.According to its hydrophobic group crosslinking association in aqueous solution,light-responsive nanogels were prepared. The Mwand Dhof the nanogels significantlychanged after irradiation under different wavelengths of light. The synthesized SpP nanogelsexisted in the following three states: Mer-Sp-form (515nm), Mer-form (535nm), andSp-form. SPP extinction kinetic dynamics and aggregation process in DMSO/H2O solventswere also analyzed. The closing reaction rate of SPP decreased with water ratio rise. The druguptake and release properties were investigated by using pyrene as a model drug. The resultsindicate that the loading efficiency increased when the feeding ratio of SpP to pyreneincreased. The release amount and rate decrease in the following order: Mer-Sp-form Mer-form Sp-form. So the release rate can be adjusted by light controlled.A light-responsive triblock copolymer of ethyl cellulose-g-poly (2-hydroxyethlmethacrylate)-g-poly (spiropyran ether methacrylate)(EC-g-PHEMA-g-PSPMA) wasprepared by atom transfer radial polymerization. Different block grafting density and lengthof grafted polymer was preparaed by changing reactive ratio. Dynamics analysis proved thatthe experiment system was suitable for ATRP and polymerization reaction was active/controlled. At the same time, the EC-g-PHEMA-g-PSPMA micellar solution ofaggregation were analyzed, and the results show that the micellar aggregation morphologywas mainly affected by hydrophilic/hydrophobic ratio. The larger the proportion ofhydrophobic core, the more adsorbed between micelles. The larger proportion of hydrophilicchain, the more separated between micelles. For PSPMA segments, the polymer closed-loopresponse time would long if have high degree of polymerization with PSPMA. The spacesteric hindrance may form with more MC structure which lead to greater slowly during theclosed-loop process. The micelle diameter can be controlled by UV and visible light. Micellescan be modulated by changing the ratio of hydrophilic PHEMA to hydrophobic PSPMA.Probe pyrene as a hydrophobic model drug was loaded onto micelles. Therefore, drug releasecould be controlled by changing light.Chitosan quaternary ammonium salt attached to surface of wood fiber. The fiber showedelectropositive and light-renponsive due to SPCOOH combined with fiber. The resultsshowed that adsorption kinetics of modified fiber showed fitted quasi first order equation.And with increasing temperature, adsorption rate constant increased on fiber. An experimentof making light-responsive paper with light responsive fiber was carried out. Light-responsivefiber showed red fluorescence under ultraviolet light irradiation, and the fiber changed tocolorless under visible light irradiation. The responsive paper has no difference with theordinary paper. It has the security features.Fiber macromolecular initiator was firstly synthesized by direct acylation of fiber with2-bromopropionyl bromide. And a light-responsive fiber grafed poly (spiropyran ethermethacrylate)(Fiber-g-PSPMA) was prepared by atom transfer radial polymerization. Thehydrophilicity of functionalized paper was reduced due to spiropyran graftedpolymerizationon the fiber surface. Functionalized paper showed red fluorescence under ultraviolet lightirradiation, and the paper changed to colorless under visible light irradiation. This because Spunderwent isomerization, it changed into merocyanine (Mer) under UV. And the Mermolecule was exposed to visible light, it reverted into colourless Sp. Functionalized paper hasdouble fluorescent and color changing effects under ultraviolet light, which can be applied toanti-counterfeiting packaging materials. |
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