Size and diffusion phenomena of AOT/alcohol/water system in the presence of morin by dynamic light scattering Ajaya Bhattarai 1 , Hanna Wilczura-Wachnik * Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw 02-093, Poland ARTICLE INFO Article history: Received 21 August 2014 Received in revised form 13 November 2014 Accepted 14 November 2014 Available online 15 November 2014 PubChem: AOT (Pubchem CID: 23673837) Morin(Pubchem CID: 16219651) 1-Decanol (Pubchem CID: 8174) Ethanol (Pubchem CID: 702) Keywords: Morin Ethanol n-Decanol Surfactant Hydrodynamic radius DLS ABSTRACT Presented paper is a continuation of our studies on morin interaction with AOT (sodium bis(2-ethylhexyl) sulfosuccinate) reversed micelles solutions in two solvents: ethanol and n-decanol. Now we focused on morin influence on size and diffusion phenomena in the system morin/solvent/AOT/water. In this paper precise measurements of dynamic light scattering (DLS) of the effects of temperature, solvents (alcohols), water on the size and diffusion of AOT reversed micelles in the morin/AOT/alcohol/water system are reported. The concentrations of AOT were varied from 0.51 to 0.78mol/L. Morin concentration in during auto-correlation function registration was not the same in each solvent because of its different solubility depending on the solvent. Water concentration in the studied systems was defined by R parameter according to relation: R = (H 2 O)/(AOT) and was equal 0 and 30 in ethanol, and 0 in n-decanol. DLS measurements were done at 298.15 and 308.15K. DLS experiment involved on detection two relaxation modes (fast and slow) in the systems containing AOT reversed micelles, water, morin and solvents (ethanol and n-decanol). The DLS data clearly show the solvent influence as well as morin presence on AOT reversed micelles size and consequently their diffusion coefficients. Contrary to n-decanol strong competition between morin and ethanol molecules in AOT reversed micelles palisade layer has been found. It suggests that morin molecules replaced ethanol in AOT reversed micelles and locate in their palisade layer strongly increasing AOT reversed micelles size. Furthermore, it was found a sharp increase in correlation radii of slow modes of AOT reversed micelles containing morin molecules and their diffusion coefficients diminishing. ã 2014 Elsevier B.V. All rights reserved. 1. Introduction The structure and properties of micelles as aggregates formed by different surfactants molecules have been extensively investi- gated by various techniques as FT-IR (Zhou et al., 2002; Correa et al., 2005), NMR (Fanun, 2007), fluorescence spectroscopy (Abuin et al., 2003; Liu et al., 1998), conductivity (Li et al., 2001; Hait et al., 2002), calorimetry (Mukhopadhyay et al., 1997; Goto et al., 1993), dynamic light scattering (DLS) (Vasquez et al., 2011; Falcone et al., 2009; Agazzi et al., 2011), small angle neutron scattering (SANS) (Kotlarchyk and Huang, 1985), and small angle X-ray scattering (SAXS) (Rozman et al., 2006; Feitosa et al., 2009; Muller et al., 2009). Among many surfactants AOT ((sodium bis(2-ethylhexyl) sulfosuccinate)) is widely studied because of its specific properties as easy solubility both in polar and non-polar solvents with aggregation in different micellar structures. AOT is an anionic surfactant commonly used to form reversed micelles in non-polar solvents (Pileni, 1989; Luisi and Magid, 1986; Correa and Soito, 1978; Fendler,1987; Liu and Guo, 2005; Long et al., 2004; Kozzlov and Andelman, 1996; Wennerstrom,1996; Kotlarchyk et al., 1982; Lee and Wyn, 1993). AOT molecules self-aggregation ability is a consequence of their amphiphilic nature. In non-polar solvent, a polar heads of surfactant molecules form an interior of such micelle, whereas non-polar hydrocarbon chains create a so-called palisade layer surrounding a polar core and are towered to non- polar bulk solvent. From applicable point of view AOT reversed micelles among many interesting advantages are able to solubilize into interior a significant amount of water (Pileni, 1989; Maitra, 1984; Bohadir and Behboudnia, 2001). The amount of water in such system is characterized by R parameter defined as water to surfactant molarities ratio (R = (H 2 O)/(AOT)) (Correa and Soito, 1978) and in case on water concentration higher than surfactant a * Corresponding author. Tel.: +4822 241 3080. E-mail addresses: bkajaya@yahoo.com (A. Bhattarai), wilczura@chem.uw.edu.pl (H. Wilczura-Wachnik). 1 Permanent address: Department of Chemistry, M.M.A.M.C., Tribhuvan Univer- sity, Biratnagar, Nepal. http://dx.doi.org/10.1016/j.ijpharm.2014.11.037 0378-5173/ ã 2014 Elsevier B.V. All rights reserved. International Journal of Pharmaceutics 478 (2015) 610–616 Contents lists available at ScienceDirect International Journal of Pharmaceutics journal homepage: www.elsevier.com/locate/ijpharm