ELECTROSTATIC SPRAYING - A NOVEL TECHNIQUE FOR PREPARATION OF POLYMER-COATINGS ON ELECTRODES

A liquid now emerging from a tip or a thin tube under the influence of a strong electric field will, due to charging of the dielectric liqui d, break up into small droplets. Thus, if a polymer material is dissol ved in the liquid, this electrodeposition technique can be utilized fo r producing polymer coatings on electrodes, The method was applied for in situ formation of ultrathin (similar to 3000 Angstrom) cellulose a cetate (CA) phase inversion membranes on glassy carbon electrodes. The purpose of the membrane was to protect the electrode surface from fou ling by macromolecular species, The spraying liquid consisted of CA, a cetone, and aqueous magnesium perchlorate as pore former, and the spra ying voltage was 14 kV, Profilometric measurements showed that the thi ckness of the spray-cast membranes was much more uniform than that of similar membranes formed by solvent casting By using cadmium and lead as test analytes and differential pulse anodic stripping voltammetry a s detection method, it was found that the membranes prepared by spray casting offered better protection against interference from poly(ethyl ene glycol) (PEG) 6000 than those prepared by solvent casting. Also, t he interference from PEG 2000 was significantly reduced. Experimental details of the electrostatic spraying technique are given.