Polyaniline coating on glass and PMMA microspheres

Hollow glass and polymethylmethacrylate (PMMA) microspheres having a diameter of 50-100 and 20-80 μm, respectively, were coated with an overlayer of polyaniline p-toluenesulphonate (PANI-PTSA) and polyaniline camphorsulphonate (PANI-CSA) using the chemical oxidative polymerization of aniline on the surfaces of these microspheres. In both cases it was found that PANI coatings are obtained from deposition of PANI precipitate from the reaction medium on the surface of microspheres. The surface coverage due to PANI coating on glass microspheres is around 0.252 g/m2. However, in PMMA microspheres it is 1.818 g/m2 for PANI-PTSA and 1.989 g/m2 for PANI-CSA. Thus, the average surface coverage in coated PMMA microspheres is more than that in coated glass microspheres. This may be due to the polymeric nature of the surface of PMMA microspheres. In case of glass microspheres, the average content is same for both the PANI-CSA and PANI-PTSA coatings. However in case of PMMA microsphere, the average coating content is slightly more for PANI-CSA than PANI-PTSA coatings. The coated and uncoated microspheres were characterized using optical microscopy.