Evaluation of Surface Active Properties and Voltammetric Characterizations of Some New Anionic Copolymer Surfactants

Abstract

The onset of micelles formations critical micelle concentration, diffusion coefficients as well as particle sizes for some new synthesized anionic copolymer surfactants PSA_4a, PSA_4b, and PSA_4c, were determined and discussed. Three different electrochemical techniques such as cyclic voltammetry (CV), rotating disk voltammetry (RDV), and chronocoulometry (CC) were used in this investigation. The voltammetry of electroactive hydrophobic probe ferrocene solubilized surfactants was investigated in aqueous buffer carbonate solutions of pH 10. The CMC for each PSA_4a, PSA_4b, and PSA_4c, was found to be 3.20 × 10⁻⁴, 4.60 × 10⁻⁴ and 6.30 × 10⁻⁴ M, respectively, using both CV and RDV techniques. The amount of adsorption contribution of ferrocene solubilized surfactants at the glassy carbon electrode was determined from chronocoulometric measurements and it was found in the range from (1.4 to 2.7) × 10⁻¹⁵ M. The apparent diffusion coefficients were estimated from RDV measurements and the real micelles diffusion coefficients were obtained. Re-quilibrium considerations of ferrocene probe kinetics at the electrode surface were treated according to two different modes of slow- and fast-kinetics. The corrected diffusion coefficient values showed constancy at (5.3 ± 0.1) × 10⁻⁷, (4.8 ± 0.1) × 10⁻⁷, and (3.6 ± 0.4) × 10⁻⁷ cm²/sec for PSA_4a, PSA_4b, and PSA_4c, respectively in the concentration range from 20 to 200 mM. The morphological features of anionic copolymeric surfactants PSA_4a, PSA_4b, and PSA_4c, micelles showed globular self-assembled structure.

Keywords:

• Copolymeric surfactants
• morphology
• onset of micelles formations
• re-equilibrium kinetics
• surface properties
• voltammetry

Current address for S. A. Y.: Almajmaah University, Saudi Arabia; Current address for W. I. A. E.-D.: Umm Al-Qura University, Saudi Arabia.

Notes

*Ref. (18).