Conductivity and X-ray photoelectron studies on lithium acetate doped chitosan films

Chitosan, ethylene carbonate (EC) and lithium acetate (LiOAc) were mixed in the desired proportions and dissolved in 100 ml of 1% acetic acid solutions. The solutions were then poured into various petri dishes and left to form films at room temperature. Complexation was confirmed by X-ray photoelectron spectroscopy (XPS). The lithium signal can be deconvoluted into three gaussian component peaks. One of the peaks at ∼55 eV is attributed to Li–N interaction. The nitrogen signal can be deconvoluted into two gaussian component peaks. The peak at ∼403.1 eV is attributed to N–Li interaction. The electrical conductivity of all samples was calculated using the bulk resistance value obtained from the complex impedance plot in the frequency range between 1 kHz and 1 MHz. The highest electrical conductivity obtained for the film containing LiOAc is 7.6×10−6 S cm−1 at room temperature. The plot of conductivity, σ versus dopant content indicates that σ increases with increasing dopant content up to a dopant amount of 0.8 g LiOAc. The plot of ln σT versus 103/T for each lithium acetate sample between 298 and 363 K shows beys Arrhenius behavior indicating that the conductivity occurs by way of some thermally assisted mechanism. The chitosan based samples may have potential use in replacing the liquid components of electrochromic devices.