Morphology and Property Analyses of Thermo-responsive and Conductive Composite Fibers with Sheath-Core Structure

• Main Authors: Fang-Tzu Chang, 張芳慈
• Other Authors: 邱文英
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/27863942213569786210

碩士 === 國立臺灣大學 === 化學工程學研究所 === 102 === In this research, thermo-responsive and conductive composite fibers with sheath-Core structure were fabricated by co-axial electrospinning. The thermo-responsive and thermo-crosslinkable copolymer poly(NIPAAm-co-NMA) (PNN) and conductive PEDOT:PSS were mixed as the sheath material and the flexible copolymer poly(butylacrylate-co-styrene)(PBS) was prepared as the core. Thermo-responsive copolymer PNN which composed of N-isopropylacrylamide (NIPAAm) and N-methyloacrylamide were synthesized by solution polymerization. Flexible copolymer PBS which composed of butylacrylate and styrene were synthesized by emulsion polymerization.In this co-axial electrospinning process, the core solution was prepared by dissolving PBS in chloroform.Two kind of sheath solution was prepared for electrospinning process：(1) PNN/PEDOT:PSS in water、(2) PNN/PEDOT:PSS in water＋DMSO. The morphology of the composite fibers were observed by SEM and TEM. To fabricate optimum sheath-core fibers, the critical viscosity of the core solution should exceed 1Pa．s. The outer diameters of fibers were about 250-350nm and the inner diameters were about 150-200nm. In the first method, The fiber mat should be doped by DMSO after thermal curing to enhence conductive property, but it was found out that the core material PBS was partially dissolved. In the thermo-responsive conductive property measurement, surface resistivity of fiber mat would change with temperature.When the temperature increased from 25℃ to 50℃, the surface resistivity of this fiber mat decreased gradually owing to thermo-responsivity. In the flexibility test, after bending this fiber mat several times, it would fracture easily owing to leakage of PBS. To solve this problem, we used the second method. By changing the solution, fiber mat wouldn’t be necessary to be doped in DMSO after thermal curing. The flexibility of sheath-core composite fiber mat was improved because of the higher content of PBS. In the thermo-responsive conductive property measurement,because the working temperature was near the Tg of PBS, the surface resistivity was disturbed by motion of PBS chains.