Functional polymer grafted nanoparticles synthesis, characterization and applications

Incorporating nanoparticles and polymers into one composite material have opened new pathways for generating novel material structures and advancing the properties of conventional materials. The developments in the field of nanocomposites have been accelerated by the progress in fabrication of nanoparticles with designed shape and precise size control, surface modification techniques covering a variety of nano-scale materials including clay sheets, carbonaceous materials, metal oxide particles, etc., as well as new syntheses of polymers with targeted architecture and functionality. The control of interfacial interactions is the key to property enhancement of almost all nanocomposite materials. Grafting polymer chains directly onto the surface of nanoparticles is a relatively new approach for obtaining novel nanocomposite structures and it offers better control of grafting density and maximizes the interfacial interactions between nanoparticles and polymeric matrices.

The first project in this thesis describes the preparation of nanocomposites via surface initiated polymerization of block copolymer chains directly from the surface of montmorillonite clay. A ‘graft-from’ synthesis protocol was developed for the preparation of the nanocomposites. Comprehensive material characterization was performed to understand the structure and properties of the nanocomposites. Crystallization behavior of the bulk material and optical properties of nanocomposite films were examined. The relationship between material synthesis, structure and properties is also discussed in these chapters.

The second project involves grafting polyelectrolytes onto magnetic nanoparticles for the application of electromagnetic imaging in high temperature, high salinity gas and oil reservoir environments. The fabrication of magnetic nanoparticles is described with a focus on both size control and achieving colloidal stability. The synthesized nanoparticles were used as core materials for their outstanding magnetic properties. Subsequent surface functionalization and a ‘grafting-to’ method was developed to coat the nanoparticles with a surface layer of polyelectrolytes, which provides nanoparticles with excellent transport mobility for high temperature, high salinity aqueous flow conditions through porous rock and sediment.