Effect of Fiber Orientation on Ionic Conductivity of Electrospun Polyimide Nanofibers Mats

전기방사 폴리이미드 나노섬유매트의 섬유배향이 이온전도도에 미치는 영향

  • Huh, Yang-Il (Faculty of Applied Chemical Engineering, Chonnam National University) ;
  • Kim, Young-Hee (WCU Research Team, Department of Polymer-Nano Science and Technology, Chonbuk National University) ;
  • Ahn, Jou-Hyeon (Department of Chemical and Biological Engineering and Engineering Research Institute, Gyeongsang National University) ;
  • Lee, Hong-Ki (Fuel Cell Regional Innovation Center, Woosuk University) ;
  • Nah, Chang-Woon (WCU Research Team, Department of Polymer-Nano Science and Technology, Chonbuk National University)
  • 허양일 (전남대학교 응용화학공학부) ;
  • 김영희 (전북대학교 공과대학 고분자.나노공학과 WCU 연구팀) ;
  • 안주현 (경상대학교 생명화학공학과) ;
  • 이홍기 (우석대학교 수소연료전지지역혁신센터) ;
  • 나창운 (전북대학교 공과대학 고분자.나노공학과 WCU 연구팀)
  • Received : 2010.01.18
  • Accepted : 2010.01.26
  • Published : 2010.03.30

Abstract

In this study, polyimide(PI) nanofibers mats were prepared by electrospinning and three different fiber morphologies of random, uniaxial, and biaxial orientation were prepared by controlling the speed of drum-shaped collector and other parameters. The SEM studies reveal that the aforesaid morphologies were obtained on the nano-fibrous mats prepared. The ionic conductivity was measured using an in-plane type conductivity tester for the PI mats soaked in the mixture of 1M lithium trifluoro-methane-sulfonate and tetra-ethylene glycol dimethyl ether. The ionic conductivity was surprisingly higher for the biaxial PI mats. For the uniaxially-oriented mats, the ionic conductivity was found to be higher in the parallel direction compared to the perpendicular direction of the fiber orientation. A curious cyclic fluctuation was found in the ionic conductivity with time. The observed behavior was explained by considering the distance between fibers and transport speed of ions used in this study.

본 연구에서는 전기방사 장치의 드럼형태 컬렉터의 회전속도를 조절함으로써 제조된 섬유가 랜덤 또는 배향성 (1축, 2축)을 갖는 폴리이미드(PI) 나노섬유 매트를 제조하였다. 제조된 PI 매트의 구조를 전자현미경(SEM)을 통해 관찰한 결과 전술한 배향성을 확인할 수 있었다. 1 M 리튬트리풀루오로-메탄-설포네이트와 테트라-에틸렌 글리콜디메틸 에테르의 혼합용액에 PI 매트를 침지시킨 후 이온전도기로 이온전도도를 측정하였다. 2축배향 매트가 가장 높은 이온전도도를 나타내었다. 1축 배향의 경우 이온의 이동방향과 수직방향이 평행방향보다 이온전도도가 낮게 나타났고, 아울러 일정한 주기성을 나타내었다. 주기성은 섬유간 거리와 이온 속도를 이용하여 설명할 수 있었다.

Keywords

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