Study On The Synthesis, Modification And Properties Of Monodisperse Molecularly Imprinted Polymer Microspheres

Molecularly imprinted polymers (MIPs) are a new kind of macromolecular materials with molecular recognition capability. Because MIPs have the advantages of predetermination, specificity and practicability, they have been extensively used in chromatographic separation, antibody mimic, solid-phase extraction, biosensors, catalysing reaction and other relevant fields.Non-spheroid MIPs or spheroid MIPs with a broad bead size distribution are not ideal for applications due to their irregular shape or obvious difference in filling interspaces. However, monodisperse molecularly imprinted polymer microspheres (MIPMs) have attracted extensive attention because of their better performance and convenient use. The traditional methods used to prepare monodisperse MIPMs are rather complex. Highly cross-linked network structure limits the diffusion of substrate in MIPMs, which results in a low adsorption rate. In addition, few studies have been done on the thermodynamics of molecular imprinting, and further research is needed to understand the function of different binding sites of MIPMs in adsorption and recognition. The aim of this thesis is to explore new methods to prepare monodisperse MIPMs with high adsorption rate, to analyse the adsorption characteristic of MIPMs, and to study the function of different binding sites of MIPMs in adsorption and recognition from the point of view of thermodynamics.Monodisperse micrometer-sized polystyrene(PS) microspheres were prepared by improving the formulas and conditions of emulsifier-free polymerization. Using the PS microspheres as seeds, 2,4-dichloro-6,7-dimethoxyquinazoline(DCQAL) as template molecules, and adopting appropriate swelling and polymerization techniques, monodisperse MIPMs with porous structure were prepared successfully by a single-step swelling and polymerization method. The factors affecting particle size, pore size and morphology of MIPMs were studied. The results indicate that particle size of MIPMs increases with the increase of swelling ratios. The particle size becomes uneven when the swelling ratio is larger than 60. An increase in the usage of solvent or crosslinker leads to a decrease in the average pore size of MIPMs and an increase in the specific area of MIPMs. However, a single big hole appears when the crosslinker usage is less than 18mmol. The solvent with less polarity facilitates the preparation of MIPMs with regular spheroid and porous structure.