The Application Of Photo-induced Polymerization In Functional Polymer Synthesis And Material Surface Modification

The photo-induced polymerization,playing a crucial role in functional polymer preparation and surface modification,has many distinct advantages such as easy to operate,mild reaction conditions and controllable polymerization process.Meanwhile,the catechol derivatives with similar structure to that of adhesive proteins of mussels can adhere to almost any types of material surface and"sulfur?VI?-fluoride exchange"click reaction?Su FEx?can be conducted quickly and efficiently without the participation of metal catalysts.Therefore,based on a new catechol-based biomimetic photoiniferter,a new method for surface functionalization in mild conditions was proposed,which is universal to both of substrates and monomers.Furthermore,a fast and efficient method for post-polymerization modification without the need of any metal catalyst was also developed by combining the SuFEx click reaction with photo-induced polymerization.The research is extended as following in three aspects:?1?Based on UV-induced polymerization,a new method for the preparation of functional surface by grafting polymerization was proposed.First,a new catechol-based biomimetic photoiniferter agent4-??3,4-dihydroxyphenethyl?carbamoyl?benzyl diethylcarbamodithioate?Dopa-DETC?was designed and synthesized,which can anchor on a variety of substrate.Then,under the UV irradiation,not only 2-?dimethyl amine?ethyl methacrylate?DMAEMA?can be grafted on the Dopa-DETC decorated surface by"Grafting from"strategy,P?DMAEMA-b-BA?block polymer brush was also prepared by re-initiated photopolymerization of 3-propylene amide benzene boric acid?BA?.Finally,the DMAEMA monomer was grafted on a Dopa-DETC decorated PVC surface in the same way described above.The thickness and surface chemical composition of different polymers-modified surface were analyzed by ellipsometry measurement,fourier transform infrared reflectance?FITR?spectroscopy,static water contact angle and X-ray photoelectron spectroscopy?XPS?measurements.The results showed that this surface modification method can not only be carried out efficiently under mild conditions,but also has universality for both monomers and substrates.?2?By combining Dopa-DETC with visible light induced grafting polymerization,poly?N-vinylpyrrolidone??PVP?polymer brush with a"Bottle-brush"structure was prepared through"Grafting from"strategy.First,under UV irradiation,poly?2-??2-bromo-2-methylpropanoyl?oxy?ethyl methacrylate??PHEMABr?and PVP polymer brush with a linear structure can be formed on the Dopa-DETC decorated surface,respectively.Then,under visible light irradiation,using the Mn₂?CO?₁₀as catalyst,PVP polymer brush with a"Bottle-brush"structure was prepared by initiating NVP polymerization by the aid of acyl bromine groups on the side chain of PHEMABr polymers.Finally,PVP-b-PMAG block copolymer brush was also prepared by re-initiated photopolymerization of methyl-acryloyl glucosamine?MAG?.The protein repelling properties of PVP-modified surface with different topological structures was analyzed by quartz crystal microbalance and fluorescence confocal measurement.The results indicated that compared with PVP brush with a linear structure,brush with a"Bottle-brush"structure showed a more)tructure,brush with a"Bottle-brush"structure showed a more excellent ability in resisting proteins adsorption.At the same time,it can also specifically adsorb proteins.?3?By combining photo-induced polymerization with SuFEx click reaction,a fast and efficient method for post-polymerization modification without any metal catalyst was proposed.First,a new kind of photoiniferter agent 4-?fluorosulfonyl?benzyl diethylcarbamodithioate?FSB-DECT?containing both of dithiocarbamates and sulfonyl fluoride moieties was developed to act as the photoinitiator and click sulfur?VI?-fluorideexchange?SuFEx?agent.Second,the photopolymerization behavior of FSB-DECT was demonstrated via standard photoiniferter-mediated polymerization for various types of monomer including N-isopropylacrylamide?NIPAAm?,glycidyl methacrylate?GMA?,and vinyl acetate?VAc?.The data of gel permeation chromatography?GPC?and nuclear magnetic resonance spectroscopy?NMR?showed that the polymerization was relatively well controlled.Finally,using the sulfonyl fluoride endfunctionalized poly?N-isopropylacrylamide?as a model polymer,the potential appication of the SuFEx reaction for efficient post-polymerization functionalization was demonstrated.