Formation of Hollow Nanoparticles by Inclusion and Decomposition of Azo Compounds and Their Properties

Abstract

Polymer particles are widely used in various fields, such as paintings. When the particles were adsorbed on the substrate by electrostatic force, it was important to develop techniques for removing the particles from the substrate. We used 2,2’-azobis(2-methylbutyronitrile) (V-59) as a foaming agent to make the particles desorbed from the substrate. First, polystyrene particles with positive charges were prepared by soap-free emulsion polymerization. Second, V-59 was added to the polymer colloid solution to encapsulate V-59 by the polystyrene particles. The particles were adsorbed on the mica substrate with negative charges. Finally, the mica substrates were heated in water to emit the nitrogen gas generated by the decomposition of V-59 inside the polymer particles adsorbed on the mica surface. To evaluate the desorption efficiency of this method, the mica coated with adsorbed particles was observed using SEM to calculate the surface coverage from the SEM images. The desorption ratio increased with the amount of V-59 inside the polystyrene particles. Therefore, the nitrogen gas emitted from V-59 inside the particles played an important role in removing the particles from the mica surface. This removal method is environmentally friendly because it does not involve the use of organic solvents.

Graphical Abstract

Chemical reaction of V-59 and desorption of particles from the substrate by nanobubbles generated from inside the particles by heating.