Surfactants with colloids: Adsorption or absorption?

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:449

Article

Smith, Gregory N.¹  Grillo, Isabelle²  Rogers, Sarah E.³  Eastoe, Julian¹ 

[1] Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England

[2] Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France

[3] Rutherford Appleton Lab, ISIS STFC, Didcot OX11 0QX, Oxon, England

关键词: Colloids;    Small-angle neutron scattering;    Nonpolar solvents;   

DOI  :  10.1016/j.jcis.2014.12.048

来源: Elsevier

【 摘 要 】

Hypothesis: The interaction of Aerosol OT (AOT) surfactant with systems of model colloids in nonaqueous solvents (water-in-oil microemulsions, surfactant-stabilized silica organosols, and sterically-stabilized PMMA latexes) is expected to be system specific. Two limiting cases are expected: adsorption, with surfactant located at the particle surfaces, or absorption, with surfactant incorporated into the particle cores. Experiments: Two approaches have been used to determine how AOT is distributed in the colloidal systems. The stability of the colloids in different alkanes (heptane to hexadecane, including mixtures) has been studied to determine any effects on the colloid surfaces. Contrast-variation small-angle neutron scattering (SANS) measurements of the colloid cores and of AOT-colloid mixtures in colloid-matched solvent have also been performed. Normalization to account for the different scattering intensities and different particle radii have been used to enable a system-independent comparison. Findings: AOT in water-in-oil microemulsions and surfactant-stabilized silica organosols is determined to be adsorbed, whereas, surprisingly, AOT in sterically-stabilized PMMA latexes is found to be absorbed. Possible origins of these differences are discussed. (C) 2015 The Authors. Published by Elsevier Inc.

【 授权许可】

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