Preparation And Application Research Of Photoresponsive Surface Molecularly Imprinted Materials Based On Organic/inorganic Substrate

Photoresponsive surface molecularly imprinted polymer?PSMIP?refers to a novel type of polymer material obtained through combining stimuli-responsive polymer with surface imprinting technique.Compared to traditional photoresponsive molecularly imprinted polymers,PSMIP has more excellent performance including more accessible binding sites,rapid transfer rate of target substance,higher separation efficiency,and effectively reducing the chances of azobenzene monomer to be "embedded",thereby increasing the rotation space of azobenzene chromophore.PSMIP has a wide range of applications in chemical sensors,intelligent separation and extraction,artificial antibodies and drug release and so on.However,for the PSMIP using organic materials such as silica as the substrate,the experimental condition for etching the substrate is harsh and shell morphology is irregular.Moreover,the trans?cis photoisomerization of azobenzene occurred upon a UV irradiation.To address the first challenge,an organic polymer carboxylated polystyrene microspheres were used as the SMIP substrate for convenient removal of the substrate.To address the second challenge,Upcoversion material NaYF₄: Yb: Er was used at the substrate,the interaction between azobenzene and NaYF₄: Yb: Er are expected to realize the trans ?cis photoisomerization upon visible irradiation.This dissertation contains five chapters,specific contents are described as follows:1.In Chapter One,the research progress,the type of substrate,the function of griseofulvin and 4-ethylphenol,and the conventional detection methods for griseofulvin and 4-ethylphenol have been reviewed.The purpose and significance of this work were raised.2.In Chapter Two,a rapid detection method for griseofulvin was established.The core-shell structured PSMIP?PS-MAA@MIP?was prepared by precipitation polymerization on PS-MAA surface using MAPADSA,griseofulvin,and triethanolamine trimethacryl ester?TEOHAMA?as functional monomer,template molecule,and cross-linker,respectively.The optimum conditions for the synthesis of carboxyl polystyrene microspheres,the types of crosslinking agents and the effect of MIP-film thickness on PS-MAA were investigated.PS-MAA@MIP was fabricated based on the optimized conditions,and its morphology,structure,and imprinting efficiency were characterized.The influence of griseofulvin concentrations on the isomerization rate of the SMIP materials was investigated.A new method for the detection of trace griseofulvin was developed.This method was applied for detection of griseofulvin in biological samples with the advantages of rapidness,simplicity,avoiding large instruments,and high limit of detection?0.2ppm?.3.In Chapter Three,a photoresponsive hollow MIP?PHMIP?was obtained after removal of the sacrificial PS-MAA substrate of PS-MAA@MIP using CHCl3 solution.The effect of different solvents on the shell morphology was studied and optimized.The morphology,structure,and imprinting efficiency of PHMIP were studied.Compared to PS-MAA@MIP,HMIP had better performance.HMIP was used for the detection of griseofulvin in biological samples such as milk and emollient water.4.In Chapter Four,a rapid detection method for 4-ethylphenol was established.Using azobenzene derivatives?MADPADSA?as the functional monomer,4-ethylphenol?4-EP?as the template,TEOHAMA as a crosslinker,NaYF₄@MIP were prepared on the surface of NaYF₄: Yb: Er by precipitation polymerization.The effect of NaYF₄ on the isomerization rate of the materials was investigated.NaYF₄@MIP displays rapid trans?cis isomerization upon visible light irradiation.A new method for detection of 4-EP was established,and applied for the determination of 4-EP in red wine.This method is quick,simple,and independent of large instruments.5.In the last chapter,the results and conclusions were summarized,and some recommendations for future work were given.