Hossein Fashandi - Department of Textile Engineering, Amirkabir University of Technology, Tehran, Iran.
Mohammad Karimi - Department of Textile Engineering, Amirkabir University of Technology, Tehran, Iran.

Fabrication of very fine fibers whose diameters fall in the range of micro to nanometers via the so-called electrospinning process is of scientific and continuing interest. The principleof electrospinning has been extensively discussed in literature [1]. Considering the potential applications of nanofibers in avariety of scientific and commercial areas such as drug delivery and tissue engineering, nanocomposite, filtration, cosmetics, protective clothing and developing superhydrophobicsurfaces, it can be clearly concluded that morphology of electrospun fibers has the prevalent role ontheir final application. For example, porous nanofibers have found applications in specific fields requiring high surface area such as catalytic systems and membranes in sensingmaterials [2]. Evidence for variation of morphology of polystyrene electrospun fibers with relative humidity was firstreported by Pai et al. [3] who demonstrated that increasing the relative humidity of electrospinning chamber leads to morphology change from wrinkled surface and solid crosssectionto solid surface and porous cross-section. Furthermore, some researchers [4] have reported formation of porous fibers by electrospinning a ternary system of nonsolvent/solvent/polymer. This contribution is aimed to present a study on the influence of electrospun fiber diameteron its interior morphology at different levels of relative humidity of electrospinning atmosphere