Abstract
We describe in this paper different and complementary experimental methods for assessing the adsorption of surfactants on metal particles in oil-based suspensions. Two different kinds of particles are dispersed in mineral oil: iron microparticles and CoNi nanoparticles. The adsorption of oleic acid in the Fe/oil interface in diluted suspensions can be determined by obtaining the adsorption isotherm. In addition, we present a method based on the time evolution of the optical absorbance of suspensions, from which the existence of adsorption can be inferred. For concentrated suspensions, the used of optical methods is not recommended, since they are affected by a significant inaccuracy. We present here a useful alternative based on electromagnetic induction phenomena. The results obtained allow a more comprehensive knowledge of the aggregation process in concentrated suspensions. With the same purpose, a third group of experiments, based on rheological techniques, is carried out in Fe/oil and CoNi/oil concentrated suspensions. In these series of experiments, the effect of three surfactants (oleic acid, aluminum stearate and lecithin) is tested by measuring either the viscosity, or the magnetic field-induced yield stress of the suspensions. The combination of these series of experiments gives us valuable information about the most appropriate surfactant/carrier combination capable of imparting a high stability and a strong magnetorheological response in magnetic colloids.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barnes, H.A., Hutton, J.R., Walters, K.: An Introduction to Rheology. Elsevier, Amsterdam (1998)
Batchelor, G.K.: Effect of Brownian-motion on bulk stress in a suspension of spherical-particles. J. Fluid Mech. 83, 97–117 (1977)
Bossis, G., Volkova, O., Lacis, S., Meunier, A.: Magnetorheology: fluids, structures and rheology. In: Odenbach, S. (ed.) Ferrofluids, pp. 202–230. Springer, Berlin (2002)
Drach, M., Andrzejewska, A., Ciesla, J., Narkiewicz-Michalek, J.: Theoretical description of aggregation of cationic emini surfactants in the bulk solution and on the silica surface. Adsorption 14, 629–638 (2008)
Gómez-Ramírez, A., López-López, M.T., Durán, J.D.G., González-Caballero, F.: Influence of particle shape on the magnetic and magnetorheological properties of nanoparticle suspensions. Soft. Matter. 5, 3888–3895 (2009)
Krieger, I.M., Dougherty, T.J.: A mechanism for non-Newtonian flow in suspensions of rigid spheres. Trans. Soc. Rheol. 3, 137–152 (1959)
Larson, R.G.: The Structure and Rheology of Complex Fluids. Oxford University Press, New York (1999)
López-López, M.T., de Vicente, J., Bossis, G., González-Caballero, F., Durán, J.D.G.: Preparation of stable magnetorheological fluids based on extremely bimodal iron-magnetite suspensions. J. Mater. Res. 20, 874–881 (2005a)
López-López, M.T., de Vicente, J., González-Caballero, F., Durán, J.D.G.: Stability of magnetizable colloidal suspensions by addition of oleic acid and silica nanoparticles. Colloids Surf. A 264, 75–81 (2005b)
López-López, M.T., Zugaldía, A., González-Caballero, F., Durán, J.D.G.: Sedimentation and redispersion phenomena in iron-based magnetorheological fluids. J. Rheol. 50, 543–560 (2006)
Mittal, K.L. (ed.): Surface and Colloid Science in Computer Technology. Plenum, New York (1987)
Rosen, M.J.: Surfactans in Emerging Technologies. Dekker, New York (1987)
Rosen, M.J.: Surfactants and Interfacial Phenomena. Wiley, Hoboken, New Jersey (2004)
Rosensweig, R.E.: Ferrohydrodynamic. Cambridge University Press, Cambridge (1985) p. 48
Sabah, E., Turan, M., Celik, M.S.: Adsorption mechanism of cationic surfactants onto acid- and heat-activated sepiolites. Water Res. 36, 3957–3964 (2002)
Somasundaran, P.: Energetics of Adsorption at Interfaces. In: Mohan Rao, M. et al. (eds.) Thermodynamics and Kinetics of Metallurgical Processes. The Indian Institute of Metals, Calcutta (1985)
Somasundaran, P., Shrolri, S., Huung, L.: Thermodynamics of adsorption of surfactants at solid–liquid interface. Pure Appl. Chem. 70, 621–626 (1998)
Author information
Authors and Affiliations
Corresponding author
Additional information
Prof. Waksmundzki always impressed me for his vitality and enthusiasm to confront new scientific challenges and for his compromise with the education of young scientists. Let this paper be a small piece of gratitude and honor to his Memory.
Rights and permissions
About this article
Cite this article
López-López, M.T., Gómez-Ramírez, A., Iglesias, G.R. et al. Assessment of surfactant adsorption in oil-based magnetic colloids. Adsorption 16, 215–221 (2010). https://doi.org/10.1007/s10450-010-9229-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10450-010-9229-y