Preparation of Polyacrylonitrile-based Carbon Nanofibers by Electrospinning and Their Capacitance Characteristics

In this work, polyacrylonitrile (PAN) fiber was prepared by electrospinning methods from dimethyl formamide solutions with various conditions, such as 8~20 kV applied voltage, 5~15 wt% PAN concentration, and 15 cm tip-to-collector distance (TCD). The nanofibers were stabilized by oxidation at $250^{\circ}C$ for 1 h, and then subsequently carbonized at $800{\sim}1000^{\circ}C$ for 1 h. The structured characteristics of the nanofibers before and after carbonization were studied by Fourier transform infrared spectroscopy. The resulting diameter distribution and morphologies of the nanofiber were evaluated by scanning electron microscope analysis. The electrochemical behaviors of the nanofiber were observed by cyclic voltammetry tests. From the results, the diameter of electrospinning nanofibers was predominantly influenced by the concentration of polymer solution and the applied voltage. The average diameter of the fibers was decreased with increasing the polymer concentration up to 10wt%. It was also found that the nanofibers with uniform diameter distribution and fine diameter could be achieved at 15kV input voltage and 15 cm TCD.

전기방사에 의한 폴리아크릴로니트릴계 탄소나노섬유 제조와 커패시턴스 특성

본 연구는 polyacrylonitrile (PAN)를 dimethyl formamide (DMF)에 용해시켜 전압조건을 8~20 kV, PAN 농도조건을 5~15 wt%, 그리고 tip-to-collector distance (TCD)를 15 cm로 다양한 조건에서 전기방사를 실시하였다. 나노섬유는 $250^{\circ}C$에서 1 h 동안 안정화시켰으며, $800{\sim}1000^{\circ}C$에서 1 h 동안 탄화시켰다. 안정화와 탄화 전후의 나노섬유의 구조 특성은 FT-IR 장비를 이용하여 연구하였으며 나노섬유의 직경분포와 모폴로지 특성을 알기 위해서 SEM 분석장비를 이용하였다. 나노섬유웹의 전기화학적 특성은 순환전류 전압곡선 특성 실험을 통해 고찰하였다. 실험 결과로부터 전기방사한 나노섬유의 직경의 크기는 일반적으로 방사용액의 농도와 인가전압에 영향을 받는다는 것을 확인할 수 있었으며 섬유의 평균 직경은 고분자의 농도 10 wt% 이상 증가함에 따라 감소하며 15 kV의 전압과 15 cm의 TCD 조건에서 섬유의 직경분포가 균일하고 평균직경이 작은 것으로 나타났다.