Preparation of bamboo-hat-shaped deposition of a poly(ethylene terephthalate) fiber web by melt-electrospinning

Melt-electrospinning is an efficient and environmentally friendly technique for producing nano/micro fibers. In the present work, the electric field distribution was analyzed by the use of ANSYS software; four poly(ethylene terephthalate) (PET) melt-electrospun fiber films were prepared within different times; bamboo-hat-shaped deposition on the plating collector was discovered and an enlarged longitudinal sectional view was exhibited for the appearance changes of four films after a series of exact external dimension measurements of fiber films. Due to bulging distribution of the electric field and accumulated charges in the film, fibers with a diameter range from 3 to 7um were produced in different spinning times and the deposition of PET fibers was bulging out. The surface morphology and structure of PET fibers produced in four consecutive 15-minute periods were investigated by scanning electron microscopy; it was found that fibers become thinner with the expansion of the deposition circle. In addition, porous and self-bonded structures in fiber films appeared late in the spinning process. The differential scanning calorimetry measurement reveals that PET fibers become crystallized and the degree of crystallinity increases with the increase of whipping radius; the melting temperature improves slightly and, by contrast, the cooling crystal temperature of various fiber films decrease late in the spinning process. The technique of melt-electrospinning to fabricate bamboo-hat-shaped fiber films is quite conducive for further researches to achieve three-dimensional structural material in a particular shape.