화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.71, No.8, 1303-1314, 1999
Interaction between iodine and ethyl cellulose
Interaction between iodine and ethyl cellulose was investigated by immersing ethyl cellulose membranes in aqueous iodine-iodide solution (iodine doping) and incorporating iodine in the solution from which the membrane was cast. Oxygen and nitrogen permeabilities in iodine-doped ethyl cellulose decrease with an increase in the concentration of iodine in the dopant solution up to 0.003 mol L-1 and increase sharply at higher iodine concentrations, and ultraviolet-visible and far-infrared spectra indicate formation of a charge transfer complex. Differential scanning calorimetry of both types of membrane shows changes in the characteristic phase transitions of ethyl cellulose after iodine treatment, including the crystal-liquid crystal transition that has been reported to occur in ethyl cellulose. Further evidence for liquid crystal phases has been found from circular dichroism. X-ray photoelectron spectroscopy of iodine-doped ethyl cellulose films indicates that the iodine is present in two different chemical states, probably l(3)(-) and l(2).