The temporal aspects of anion self-exchange in electrochemically prepared polyaniline films have been experimentally investigated. The exchange of bulkier tosylate-ferricyanide ion with Cl- ion has been monitored by photometry and electrochemical techniques. The relative changes in porosity brought about by self-exchange have been experimentally determined to be 323 and 2125/k in tosylate-exchanged and ferricyanide-exchanged polyaniline films, respectively. Scanning electron microscopy has been used to delineate the surface morphology of polyaniline films. It is seen that the polyaniline films exhibit enhanced loading of glucose oxidase after a self-ion exchange, and, hence, they can be used for the fabrication of a third-generation glucose biosensor.