Preparation and characterization techniques for nano-structured materials

Abstract

The first part of the project focused on the optimization of processes for the preparation of enzyme-containing silicagel nanoparticles and for their coating and stabilization with a polycationic layer. A procedure for coating surfaces with polymer layers was established. Atom transfer radical polymerization was used for the synthesis of a cationic macroinitiator adsorbed on the anionic surface of near-monodisperse silica nanoparticles, used as model for enzyme-containing silicagel nanoparticles. The latter were easily purified via gel filtration, while enzymatic activity was substantially retained during both macroinitiator adsorption and gel filtration. The subsequent growth of water soluble poly (glycerol monomethacrylate) (pGMMA) via ATRP onto coated enzyme-containing silicagel nanoparticles was achieved in a living fashion and with a substantial retention of the activity of encapsulated enzymes. The decoration of the surface with hydrophilic and protein-repellent polymers can provide "stealth" properties to the supported enzymes, which can be eventually functionalized to obtain more sophisticated biologically responsive nanoparticles.In the second part of the project characterization of nano-structured materials at sub-nanometer resolution was achieved by Atomic Force Spectroscopy (AFM) to probe simultaneously the structure and specific chemical and physical parameters of the system. At the same time, the force-deformation behavior of nano-structured materials subjected to concentrated loads (nanoindentation) yield detailed information and insight about their local mechanical and adhesion properties. In particular, we have focused on the characterization of nanoparticles, surface layers and self-assembled fibrillar materials, combining imaging with a local mechanical (Young‟s modulus) and physical (adhesion force and surface energy) analysis of the materials.

Date of Award	31 Dec 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Nicola Tirelli (Supervisor) & Francesco Cellesi (Supervisor)