Monday, August 19, 2013

Self-assembled nanospheres

Preparation of Core-Shell Composite Materials-Colliodal Assembly
Colloidal assembly is a process by which particles ranging in size from nanometers to micrometers are organized into structures by mixing two or more particle types. Assembly is controlled by either specific or non-specific interactions between particles. Examples include chemical bonding, biological interactions, electrostatic interactions, capillary action and physical adsorption. The assembly process is performed such that smaller particles assemble around larger ones. We are able to assemble polymer nanoparticles (50-200 nm diameter) onto silica particles (3-5 m m diameter) using specific chemical interactions (i.e. amine-aldehyde) or biospecific interactions (avidin-biotin).

Annealing the assembled composites at temperatures above the glass transition (T g ) of the polymer nanospheres allows polymer to flow and uniformly coat the microsphere surfaces. Polystyrene and poly(methyl methacrylate) nanospheres were used to produce such materials. These materials may be applied to the development of novel sensing materials for use in the artificial nose or in the development of novel stationary phases for chromatography applications.