Ionic conductivity of Poly(vinyl alcohol-co-ethylene glycol)/LiBF4

• Main Authors: Cheng-hsing Lin, 林政興
• Other Authors: Tsung-Jung Lin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/32143685278595413624

碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 98 === The ionic conductivity of poly(vinyl alcohol-co-ethylene glycol) (PVAEG) doped with lithium tetrafluoroborate (LiBF4) was studied. Experimental techniques such as X-ray diffraction (XRD) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy and optical microscopy were employed to characterize the film structure, while techniques such as dielectric spectroscopy and four point probe were used to study the ionic conductivity. The intensity of XRD peak decreased with increasing LiBF4 content. The optical microscopy study revealed that LIBF4 began to precipitate when the EG/Li molar ratio was greater than 6. There was an optimal LiBF4 concentration, EG/Li = 8, at which the ionic conductivity reached the maximum value of 2.34×10-7 S/cm. With LiBF4 concentrations higher than EG/Li=8, ion aggregation was favored and the conductivity began to decrease thereafter. The ionic conduction behaviors investigated using the dielectric spectroscopy technique also gave a result similar to that given by the 4-point probe method.