Interaction between Disodium 1,14-Tetradecanediyl Disulfate and Sodium Dodecyl Sulfate or Poly(oxyethylene) Nonyl Phenyl Ether on Alumina

Abstract

Abstract The interactions between disodium 1,14-tetradecanediyl disulfate (α,ωC14) and sodium dodecyl sulfate (SDS) or poly(oxyethylene) nonyl phenyl ether (NP 7.5) on α-alumina have been studied by measuring the zeta potential, the mean particle size, the amounts of surfactants adsorbed, and the fluorescence spectra of pyrene. When α,ωC14, SDS, or NP 7.5 as a second additive is added to alumina previously flocculated by the addition of SDS or α,ωC14, as a first additive, the flocculated alumina redisperses in the α,ωC14–SDS and α,ωC14–NP 7.5 systems. For the α,ωC14–SDS and α,ωC14–NP 7.5 systems, the redispersion of alumina proceeds in such a manner that the hydrophobic parts of SDS or NP 7.5 are in contact with the α,ωC14-coated alumina and the hydrophilic polar groups direct out to aqueous solution, resulting in the formation of mixed bilayers on the alumina, while for the α,ωC14–SDS system the adsorption of SDS on the α,ωC14-coated alumina is not enough to attain the redispersion of alumina. The measurement of the ratio I1⁄I3 of intensities of the first and third vibrionic bands of the pyrene monomer fluorescence spectra indicates that pyrene is solubilized in a much lower polar site for the α,ωC14–SDS mixed bilayer than for the mixed bilayer of α,ωC14–NP 7.5.