ABSTRACT
There is an enormous requirement for cleaner air around the world which has activated immense interests in the development of high efficiency filters or face masks. Nonwoven nanofibrous media have low basis weight, high permeability, and small pore size that make them appropriate for a wide range of filtration applications. In addition, nanofibers web offers unique properties like high specific surface area (ranging from 1 to 35 m2/g depending on the diameter of fibers), good interconnectivity of pores and the potential to incorporate active chemistry or functionality on nanoscale. To date, the most successful method of producing nanofibers is through the process of electrospinning. The electrospinning process uses high voltage to create an electric field between a droplet of polymer solution at the tip of a needle and a collector plate [1-3]. When the electrostatic force overcomes the surface tension of the drop, a charged, continuous jet of polymer solution is ejected. As the solution moves away from the needle and toward the collector, the solvent evaporates and jet rapidly thins and dries. On the surface of the collector, a nonwoven web of randomly oriented solid nanofibers is deposited. It has been found that the morphology of the web, such as fiber diameter and its uniformity of the electrospun nanofibers, are dependent on many processing parameters. These parameters can be divided into three main groups:
• Solution properties, • Processing conditions, • Ambient conditions. Each of the parameters has been found to affect
the morphology of the electrospun fibers [4].
