Solubilization parameter, equation defining

It is widely recognized that the system IFT reaches a minimum in the middle phase microemulsion region. At the same time, the solubilization parameter (a), defined as mass of oil solubilized per unit mass of surfactant, is maximized in middle phase microemulsion systems (see Figure 1). This inverse relationship between the solubilization parameter (c)and IFT (y)has been defined by the Chun-Huh equation (Huh 1979, Sunwoo et. al. 1992, Abe et. al. 1987) ... 

Solvents and solutes also interact by donor-aceptor, electron pair, and hydrogen bonding interactions. It can be predicted that the above concept is not fully universal, especially in the case of solutes and solvents which may apply these interactions in their solubilizing action. Hansen developed a three-dimensional seale with parameters to expand theory in order to include these interactions. Hansen defined solubility parameter by the following equation ... 

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