R. Sharma et al., STUDY OF ELECTRICAL-PROPERTIES OF POLYMERIC MATERIALS USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY, Journal of applied polymer science, 68(4), 1998, pp. 553-560
Electrochemical impedance spectroscopy (EIS) has been used to determin
e the water absorption characteristics of polyethylene terephthalate (
PET), polyethylene naphthalate (PEN), polyaromatic amide (Aramid), and
amine-quinone polyurethane (AQ) free-standing polymer films. A method
for calculating percent moisture uptake is presented based on capacit
ance measurements via EIS, which requires initial or ''dry'' capacitan
ce values, C-0. Three different methods for obtaining C-0 values were
described and employed, but the most reliable values were obtained via
EIS measurement using Hg contacts. C-0 values obtained by this method
resulted in calculated water uptake values nearly identical to those
obtained by measured weight gain. Lower capacitance values were observ
ed for films immersed in distilled water compared to 0.1M NaCl, which
indicates that water uptake is greater in NaCl than in pure water. The
four polymers examined in this study can be listed in order of decrea
sing resistance to moisture absorption as AQ > PET > PEN > Aramid. (C)
1998 John Wiley & Sons, Inc.