Electrostatic assembly of polyelectrolytes on electrospun fibers

Electrostatic layering of polyelectrolytes and charged titanium dioxide nanoparticles was demonstrated on the surface of polyacrylonitrile nanofibers. The surface chemistry of the electrospun fibers was modified by immersing them in a heated aqueous solution of 1.0 N sodium hydroxide. The resulting surface groups of carboxylic acid were then used to build alternanting layers of polycations and polyanions to form nanometer-scale composite archetechtures. Since the polyacrylonitrile in the nanofibers were not entirely converted to acrylic acid, the fibers remained insoluble in water, unlike electrospun polyelectrolytes. This difference allows layer-by-layer assembly that pure polyelectrolyte nanofibers do not.