(498g) Influence of Dry Ball Milling and Wet Ball Milling Conditions On Reduction in Size of ZnO Particles and On Their Morphology

Nanoparticles of Zinc Oxide have attracted the attention of lot of researchers with their unique chemical properties, low fabrication cost and variety of applications as a photo catalyst, in food packaging and in optoelctronics and biosensing. Reduction of Zinc Oxide from micron sized particles to nanoparticles has mainly been done using the technique of Planetary ball milling and Sono-fragmentation, however, as the size of ZnO reduces, its tendency to agglomerate increases due to high Van der waals forces of attraction. This agglomeration can be reduced in two ways: by maximizing the electrostatic repulsion force or by providing a barrier of steric hindrance. Wet ball milling with polymer of high molecular weight in water or in a solvent of high dielectric constant enjoys an advantage over dry ball milling with respect to agglomeration. During wet ball milling, high dispersibility, de-agglomeration and maximum reduction in size was noticed using the technique of Optical Microscopy in the case of Polymer  PAA Poly Acrylic Acid (molecular weight ~ 100,000) in water and solvent Ethylene Glycol (dielectric constant : 38) as compared to surfactant SDS Sodium Dodecyl Sulphate (molecular Weight : 288.372) and solvent Toluene (dielectric constant : 2.38) respectively. The results were also examined by the technique of scanning electron microscopy (SEM) and a maximum change in morphology was noticed in the case of dry ball milling with a rugged, spherical and shortened structure and the least change in morphology was noticed in the case of wet ball milling with PAA in water and Ethylene Glycol as solvent.