Langmuir adsorption isotherms for different organic solutions of cholesterol
Isotermas de adsorción de Langmuir para diferentes soluciones orgánicas de colesterol
C. Barnaba1,2*, M.A. García-Alvarado1, I.G. Medina-Meza3 and J.M. Tejero-Andrade1
1 UNIDA, Instituto Tecnológico de Veracruz, Miguel Ángel de Quevedo 2779, Veracruz, Ver., 91897, México. *Corresponding author. E-mail: carlo.barnaba2@gmail.com
2 Departamento de Procesos Tecnológicos e Industriales, Instituto Tecnológico y de Estudios Superiores de Occidente (ITESO), Periférico Sur Manuel Gómez Morín 8585, 45604 Tlaquepaque, Jal., México.
]]> 3 Center for Nonthermal Processing of Food, Washington State University, Pullman, WA 99164-6120, USA.
Recibido 7 de Noviembre de 2012
Aceptado 22 de Marzo de 2013
Abstract
In this work, the surfactant properties of cholesterol in organic solvents are studied. Hexane, iso-octane, iso-dodecane and toluene were used as the hydrophobic phase, and bidistilled water was used as the water phase. The captive bubbles were supported on a quartz surface and the axisymmetric drop shape analysis (ADSA) routine was performed to obtain contact angles (θ) and surface tension values (γ). Cholesterol was effective in reducing the interfacial tension of the oil/water system in all organic solvents. The appearance of turbidity associated with cholesterol crystallization is observed to be below concentration limits in all samples, because the liquid-liquid interface reduces the energy barrier required for nucleation. Experimental values of γ were adjusted with theoretical values obtained by applying Szyszkowski-Langmuir isotherm, showing good correlation between data. Finally, Szyszkowski-Langmuir constant (KL) and Gibbs energy of absorption were calculated for the binary systems.
Keywords: cholesterol, ADSA, surface tension, captive bubble, Szyszkowski-Langmuir equation.
Resumen
]]> En este trabajo se estudian las propiedades del colesterol como surfactante en soluciones orgánicas. Se utilizaron hexano, iso-octano, iso-dodecano y tolueno como fase hidrofóbica y agua bi-destilada como fase acuosa. Las burbujas cautivas se apoyan sobre una superficie de cuarzo y la rutina ADSA (Axisymmetric Drop Shape Analysis) se realizó para obtenea los angulos de contacto (θ) y los valores de tensión superficial (γ). El colesterol fue eficaz en la reducción de la tensión interfacial del sistema de aceite/agua en todos los disolventes orgánicos. En todas las muestras se observó una turbidez asociada a la cristalización del colesterol, por abajo de los límites de concentración, debido a la interfaz líquido-líquido que reduce la barrera de energía necesaria para la nucleación. Los valores experimentales de γ se ajustaron con los teóricos obtenidos aplicando la isoterma de Szyszkowski-Langmuir, mostrando una buena correlación. Por último, para los diferentes sistemas binarios se calcularon la constante de Szyszkowski-Langmuir (KL) y la energía de adsorción de Gibbs.Palabras clave: colesterol, ADSA, tensión superficial, burbujas cautivas, ecuación de Szyszkowski-Langmuir.
DESCARGAR ARTÍCULO EN FORMATO PDF
References
Adamson, A.W., Gast, A.P. (1997). Physical Chemistry of Surface, 6th Ed., John Wiley & Sons, Inc. [ Links ]
Chen, P., Kwok, D.Y., Prokop, R.M., del Rio, O.I., Susnar, S.S., Neumann, A.W. (1998). Axisymmetric Drop Shape Analysis (ADSA) and its application. Studies in Interface Science 6, 61-138. [ Links ]
]]>Chen, P., Lahooti, S., Policova, Z., Cabrerizo-Vilchez, M.A., Neumann, A.W. (1996). Concentration dipendence of the film pressure of human serum albumine at the water/decane interface. Colloids Surface B 6, 279-289. [ Links ]
Crenmer, P.S., Boxer, S.G. (1999). Formation and spreading of lipid bilayers on planar glass support. Journal of Physical Chemistry B 103, 2554-2559. [ Links ]
Demel, R.A., Joos, P. (1968). Interaction between lecithins and cholesterol at the air-water and oil-water interfaces. Chemistry and Physics of Lipids 2, 35-46. [ Links ]
Fahti-Azarbayjani, A., Jouyban, A., Chan, S.Y. (2009). Impact of surface tension in pharmaceutical studies. Journal of Pharmaceutical Sciences 12, 218-228. [ Links ]
Heimburg T. (2007). Thermal Biophysics of Membrane. Wiley-VCH, Weinheim. [ Links ]
]]>Hoorfar, M., Neumann, A.W. (2004). Axisimmetric Drop Shape Analysis (ADSA) for the determination of surface tension and contact angle. The Journal of Adhesion 80, 727-743. [ Links ]
Kadota, K., Shirakawa, Y., Matsumoto, I., Shimosaka, A., Hidaka, J (2007). Formation and morphology of asymmetric NaCl particles precipitaded al liquid-liquid interface. Advanced Powder Technology 18, 775-785. [ Links ]
Kitayama, A., Yamanaka, S., Kadota, K., Shimosaka, A., Shirakawa, Y., Hidaka J (2009). Diffusion behavior in a liquid-liquid interfacial crystallization by molecular dynamics simulations. Journal of Chemical Physics 131, 174707. [ Links ]
Kolev, V.L., Danov, K.D., Kralchevsky, P.A., Broze, G., Mehreteab, A. (2002). Comparison of the van der Vaals and Frumkin adsorption isotherms for sodium dodecyl sulfate at various salt concentration. Langmuir 18, 9106-9109. [ Links ]
Liu, Y. (2009). Is the free energy change of adsorption correctly calculated? Journal of Chemical & Engineering Data 54, 1981-1985. [ Links ]
]]>Medina-Meza, I.G., Rodriguez-Estrada, M.T., Lercker, G., García H.S. (2011). Unusual oxidative pattern in thermo-oxidation of dry films of cholesterol. Revista Mexicana de Ingeniería Química 10, 47-57. [ Links ]
Neumann, A.W., David, R., Zuo, Y. (2010). Applied Surface Thermodynamics, 2nd Ed., CRC Press. [ Links ]
Ogino, K., Onishi, M. (1981). Interfacial action of natural surfactants in oil/water system. Journal of Colloid and Interface Science 83, 18-25. [ Links ]
Pautot, S., Frisken, B.J., Cheng, J., Xie, X.S., Weitz, D.A. (2003). Spontaneous formation of lipid structures at oil/water/lipid interfaces. Langmuir 19, 10281-10287. [ Links ]
Peltonen, L., Hirvonen, J., Yliruusi, J. (2001). The behaviour of sorbitan surfactants at the water-oil interface: straight-chained hydrocarbons from pentane to dodecane as an oil phase. Journal of Colloid and Interface Science 240, 272-276. [ Links ]
]]>Prokop, R.M.; Jyoti, A., Eslamian, M., Garg, A., Mihaila, M., del Río, O.I., Susnar, S.S.; Policova, Z.; Neumann, A.W. (1998). A study of captive bubbles with axisymmetric drop shape analysis. Colloid Surface A, 131, 231-247. [ Links ]
Ross, S., Morrison, I.D. (1983). On the alleged ideality of Szyszkowski-Langmuir adsorption. Journal of Colloid and Interface Science 91, 244-247. [ Links ]
Serrano-Saldaña, E., Domínguez-Ortiz, A., Pérez-Aguilar, H., Kornhauser-Strauss, I., Rojas-González, F. (2004). Wettability of solid/brine/n-dodecane systems: experimental study of the effects of ionic strength and surfactant concentration. Colloid Surface A 214, 343-349 [ Links ]
Stalder, A.F., Melchior, T., Muller, M., Sage, D., Blu, T., Unser, M. (2010) Low-bond axisimmetric drop shape analysis for surface tension and contact angle measurement of sessile drops. Colloid Surface A 364, 72-81. [ Links ]
Uskokovic, V. (2008). Surface charge effect involved in the control of stability of sols comprising uniform cholesterol particles. Materials and Manufacturing Processes 23, 620-623. [ Links ]
Wang, H.H. (2001). Analytical model of atherosclerosis. Atherosclerosis 159, 1-7. [ Links ]
Weinberg, R.B., Cook, V.R., DeLozier, J.A., Shelness, G.S. (2000). Dynamic interfacial properties of human apolipoproteins A-IV and B-17 at the air/water and oil/water interface. Journal of Lipid Research 41, 1419-1427. [ Links ]
Xie, A.J., Shen, Y.H., Xia, B., Chen, H.B., Ouyang, J.M. (2005). Thermodynamic study of bilirubin/cholesterol mixtures at the air/water interface. Thin Solid Films 472, 227-231. [ Links ]
Zdziennicka, A., Janczuk, B. (2010). Wettability of quartz in presence of nonionic surfactants and short chain alcohol mixtures Journal of Colloid and Interface Science 343, 594-601. [ Links ]
Zdziennicka, A., Szymczyk, K., Janczuk, B. (2009). Correlation between surface free energy of quartz and its wettability by aqueous solutions of nonionic, anionic and cationic surfactants. Journal of Colloid and Interface Science 340, 243-248. [ Links ]
Zisman, W.A. (1964) Relation of the equilibrium contact angle to liquid and solid constitution. In: Contact Angle, Wettability, and Adhesion, (F. Fowkes ed., Advances in Chemistry), Pp. 1-51. American Chemical Society: Washington, DC. [ Links ]
]]>