Journal of Surface Science and Technology

S. K. Suri ¹, H. S. Randhawa ²

Affiliations
1 Department of Chemistry, Indian Institute of Technology, New Delhi 110 016, IN
2 Department of Chemistry, Punjab Agricultural University, Ludhiana 141004, IN

Abstract

The critical micelle concentration of binary surfactant systems containing sodium and four commeicial alcohol ethoxylates [CH₃ (CH₂)_n o (-CH₂ CH o-)_mH], of comparable HLB values has been determined by surface tension and spectral change methods. The results have been used to examine the micellar behaviour of the binary surfactant systems. It has been observed that alcohol ethoxylate with small hydrophopic chain (i.e. average n=9 and m=6) is compatible with sodium oleate to form mixed micelles. Surfactant systems containing relatively higher hydrophobic chain length (i.e. average n = 12.5 to 14 and m = 6.5 to 7.0) were found to exhibit non-ideal mixing behaviour resulting into a pseudo-phase separation in non-ionic rich and anionic rich micelles. The synergistic properties of the binary surfactant systems were found to be highly sensitive to the hydrophobic chain length of the non-ionic surfactant.

Keywords

Critical Micelle Concentration, Mixed Micelles, HLB, Non-Ionic Surfactants, Synergistic Effect.

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