Electrical impedance spectroscopy for determining critical micelle concentration of ionic emulsifiers
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- 作者：Samira Ghasemi ; Mariam T. Darestani ; Zohreh Abdollahi ; Brian S. Hawkett ; Vincent G. Gomes
- 关键词：Surfactant ; Electrical impedance spectroscopy ; Critical micelle concentration ionic emulsifier ; Conductometry
- 刊名：Colloids and Surfaces A: Physicochemical and Engineering Aspects
- 出版年：20 January, 2014
- 年：2014
- 卷：441
- 期：Complete
- 页码：195-203
- 全文大小：1956 K
文摘
Electrical impedance spectroscopy (EIS) was conducted to investigate the micelle formation process for ionic emulsifiers, sodium dodecyl sulfate (SDS) and Aerosol MA80. Electrical impedance values were measured with variable emulsifier concentrations at frequencies ranging from 1 Hz to 100 kHz. The data were analyzed with the help of equivalent circuits to resolve the conductance, capacitance and phase angle parameters as a function of frequency and sample concentration. The EIS parameters were found to exhibit sharp changes due to structured transformations in emulsion and established that critical micelle concentration (CMC) could be determined accurately at specific frequency ranges. We compared the capability and accuracy of measuring the CMC using the EIS impedimetry approach with that of DC conductivity measured using a conductometer for the ionic emulsifiers. We found that conductometry is not able to identify the CMC of Aerosol MA80, while the EIS is able to determine the CMC accurately for both types of emulsifiers.