Preparation And Properties Of Molecularly Imprinted Polymeric Microspheres In Aqueous System

Molecular imprinting technique (MIT) is becoming increasingly recognized as a powerful technique of preparing synthetic polymers that contain tailor-made recognition sides for certain molecules. It has an extensive application in purification, separation, immunoassay, enrichment, biomimics and other relevant fields for its predetermination, specificity and practicability of molecule recognition.This thesis gives a brief overview of the development of the principle of MIT, the preparation and application of molecularly imprinted polymers (MIP), and offers an insight into the problems met with and how the area is likely to evolve in the near future. Some amino acids and drugs imprinted spheres (MIPM ) were prepared via seeds swelling and suspension polymerization, suspension polymerization and emulsion polymerization. The physical and chemical properties of the polymers were analyzed by scanning electron microscope, thermogravimetric analyzer, electron spectrum and solid phase extraction (microextraction) technology. The imprinting and recognizing principle of MIPM in water was studied through bi-templates imprinting method as well.It was showed that MIPM between 50-300?m with macro-pores could be prepared via both seeds swelling and suspension polymerization method and suspension polymerization method, the former method could prepared the MIPM with narrower size distribution while the later one was easier to carry out and more time-saving. The morphology of the MIPM was influenced by many factors including swelling solvent, stirring speed, dosage of seeds, dispersant, dilute and progenic solvent. MIPM between 0.16-0.56?m was prepared via emulsion polymerization method, the morphology of the MIPM was mainly influenced by emulsifier, mode of monomers-addition and pH value of the polymerizing system.The result also showed that MIPM prepared in this thesis adsorbed their templates in the way of Langmiur, and their adsorption properties were influenced by the morphology of the beads and the composition of the polymers. The imprinted beads all exhibited a specific recognition to their templates, a nice regeneration property, a good separating ability to compound and remarkable enriching ability to tiny substance, and these abilities of imprinted beads were influenced by the functional monomers, the cross-linking degree of polymeric matrix and the pH value of the recognizing system etc. Functional monomers (FM) were showed to combine the templates mainly through electrostatic and hydrophobic interactions in the water system, basic FM was more suitable to acidic templates and exhibited higher recognizing ability in the system with the pH of 3.6-5.7, while acidic FM was more suitable to basic templates and exhibited higher recognizing ability in the system with the pH of 8.0-10.5. MIPM with the specific recognizing ability to biomacromolecules were prepared though epitope approach using small molecules as templates, and this approach offers a novel and feasible method of the imprinting of macromolecules on the condition that the molecule structure of the macromolecule or the epitope part is specific.