| 초록 |
Depending on the electrospinning conditions such as polymer concentration, spinning distance, additive-type and volatility of solvent, the mophology of nanofibers could be varied. The concentration or the corresponding viscosity of spinning solution is one of the most effective parameters to control the fiber morphology. With respect to polymer concentration, the structures of electrospun product can be varied from bead or beaded-fiber form to fiber structure as the concentration of spinning spolution increased gradually. The volatility of solvent could be expected to be an important parameter influencing the morphology of fibers collected on target. Porous fibers could be prepared using a highly volatile solvent under the appropriate spinning conditions, because phase separation processes take place during electrospinning. Wendorff et al. reported that porous fibers could be formed using dichloromethane (DC, boiling point 40℃) as a solvent for poly-L-lactide(PLLA), polycarbonate(PC) and polyvinylcarbazole. They also suggested that these porous nanofibers are of considerable interest for potential applications such as nanofiltration or the preparation of functional nanotubes by fiber templates. The utilization of cellulose triacetate (CTA) as membrane material has been attempted over the last three decades. CTA was known to be the material superior to cellulose diacetate due to its better hydrolytic stability and a great resistance to free chlorine and biodegradation. In the present study, we aimed to prepare the electrospun fibers with different porous structures. For this purpose, we have chosen CTA as polymer material soluble in DC because CTA has hydrolytic stability indispensable for filtration. The effect of solvent compositions including DC on the porous structures of electrospun CTA fibers was investigated.
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