Multifunctional Polymer Materials: From Synthesis to Disinfection

Abstract: Polymer materials have wide applications in many industries, such as the food, pharmacy, construction, textile, and cosmetics industries. For the past few years, polymer materials have drawn the attention of scientists and engineers as a good disinfectant due to their advanced manufacturing methods, large surface areas, good stability, and lowcost. More importantly, polymer materials can be functionalized with various chemical groups to increase their affinity towards microorganisms and broaden their applications. In this thesis, four types of multifunctional polymer materials were synthesized to investigate their disinfection ability on bacterial cells.By using molecular imprinting technology, a small molecule-chloramphenicol-imprinted polymer material of nanometer size was prepared via precipitation polymerization, and large bacteria-imprinted polymer materials of micrometer size were synthesized via surface imprinting-Pickering emulsion polymerization. Both materials had highly specific binding to the targeted template and could be used as adsorbents. In precipitation polymerization, 3-(acrylamido)phenylboronic acid was added to introduce boronic acid on the material surface. In neutral and basic aqueous solutions, boronic acid groups formed reversible boronate ester bonds with the cis-diol groups of the polysaccharides on bacterial surfaces. The release of chloramphenicol led to a high antibiotic concentration around the bacterial cells, which killed the cells. In Pickering emulsion polymerization, positively charged vinyl-functionalized polyethylenimine self-assembled with negatively charged bacterial cells and acted as a stabilizer for the emulsion. Therefore, bacteria-recognition sites based on the bacteria’s physical property formed on the surface of polymer beads after crosslinking polymerization. Ag+ was released from the preloaded hydrophobic Ag nanoparticles in the polymer beads to deactivate the bound bacterial cells.To realize multifunctional materials for antibacterial applications, nanometer sized polymer materials were prepared with glycidyl methacrylate by precipitation polymerization and microemulsion polymerization. The epoxide groups were opened by polyethylenimine, which was further used to stabilize Ag nanoparticles. The final material selfassembled with bacterial cells via electrostatic interactions. The amino groups and Ag nanoparticles endowed the composite material with disinfection ability. The molecular spectra of bacteria could also be acquired via surfaceenhanced Raman scattering from the surface Ag nanoparticles.In addition to spherical polymer materials, temperature tunable deactivation polymers were also synthesized with (methacryloyloxy)ethyl]trimethylammonium by atom transfer radical polymerization, which was initiated by an initiator containing a boronic acid group. By further modification of the terminal alkyl bromide, a fluorescent molecule,fluorescein 5(6)-isothiocyanate, was added to the polymer chain. The obtained polymers self-assembled with bacterial cells via reversible boronate ester bonds and electrostatic interactions. At 40 ℃, the polymers showed effective deactivation of bacterial cells via a synergistic effect. At 20 ℃, the polymers displayed lower or no toxicityto bacterial cells and could be used to label bacterial cells in flow cytometry and fluorescence imaging.