Polymer membranes loaded with lipids for taste sensing: electrochemical impedance spectroscopy studies [An article from: Desalination]

This digital document is a journal article from Desalination, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Poly(vinyl chloride) membranes loaded with lipids in contact with a solution to be tasted (citric acid) were characterized by electrochemical impedance spectroscopy in a frequency range from 100 kHz to 0.1 Hz of AC signal. Positively charged electrode membranes (with benzylhexadecyldimethylammonium chloride or hexadecylamine) and negatively charged membranes (elaidic acid, cholesterol or 1-dodecanol) were investigated. Impedance measurements distinguished four different time constants: high-frequency resistance R"h"f"r, medium-range frequency resistance and capacitance in series R"MC"M, charge transfer resistance R"C"T with capacitive element C"C"T, and diffusion impedance Z"W measured as the Warburg coefficient @s Values of R"h"f"r were not sensitive to the outer electrolyte concentration for all membranes. Medium-frequency resistance, R"M, was found to be dependent on the outer electrolyte concentration for both types of membranes. Charge transfer resistance was negligible only for positively charged membranes. They exhibited lower diffusion impedance in comparison to negatively charged membranes.