TY - JOUR
T1 - The effect of structural variation of alcohols on water solubilization in nonionic microemulsions
T2 - 1. From linear to branched amphiphiles - General considerations
AU - Ezrahi, S.
AU - Tuval, E.
AU - Aserin, A.
AU - Garti, N.
PY - 2005/11/1
Y1 - 2005/11/1
N2 - This article is the first part of a two-part study that exemplifies how to treat the solubilization of water in multicomponent surfactant-based systems. In particular, it aims at clarifying the role of cosurfactants in water solubilization in these systems. The judicious selection of the components in such systems to maximize water solubilization is occasionally thought to be dictated by the chain length compatibility principle, which may be expressed quantitatively by the BSO (Bansal, Shah, O'Connell) equation. Here we demonstrate some limitations of the equation. For example, in our best model system, C12(EO)8/dodecane + pentanol = 1:1 (by weight)/water at 27±0.2°C, the BSO equation predicts that no alcohol is needed for maximum water solubilization, contrary to our experimental findings. We discuss how to optimize the alcohol/oil weight ratio needed for stabilizing four-component microemulsions. In our model systems C 12(EO)8 or C18:1(EO)10/pentanol/ dodecane/water, this optimal weight ratio is 1:1. We also highlight the difference between the effect of normal alcohols on water solubilization - which passes via a maximum - and their effect on percolation processes and structured changes of proteins, which depends solely upon the alcohol hydrophobicity. For the investigation of the effect of branching on phase behavior the utilization of an extended form of the geometrical branching factor Fb is suggested. The meaning of this factor is elucidated by comparing it with topological indices.
AB - This article is the first part of a two-part study that exemplifies how to treat the solubilization of water in multicomponent surfactant-based systems. In particular, it aims at clarifying the role of cosurfactants in water solubilization in these systems. The judicious selection of the components in such systems to maximize water solubilization is occasionally thought to be dictated by the chain length compatibility principle, which may be expressed quantitatively by the BSO (Bansal, Shah, O'Connell) equation. Here we demonstrate some limitations of the equation. For example, in our best model system, C12(EO)8/dodecane + pentanol = 1:1 (by weight)/water at 27±0.2°C, the BSO equation predicts that no alcohol is needed for maximum water solubilization, contrary to our experimental findings. We discuss how to optimize the alcohol/oil weight ratio needed for stabilizing four-component microemulsions. In our model systems C 12(EO)8 or C18:1(EO)10/pentanol/ dodecane/water, this optimal weight ratio is 1:1. We also highlight the difference between the effect of normal alcohols on water solubilization - which passes via a maximum - and their effect on percolation processes and structured changes of proteins, which depends solely upon the alcohol hydrophobicity. For the investigation of the effect of branching on phase behavior the utilization of an extended form of the geometrical branching factor Fb is suggested. The meaning of this factor is elucidated by comparing it with topological indices.
KW - BSO equation
KW - Branching factor
KW - Nonionic microemulsions
KW - Water solubilization
UR - http://www.scopus.com/inward/record.url?scp=25844505145&partnerID=8YFLogxK
U2 - 10.1016/j.jcis.2005.04.097
DO - 10.1016/j.jcis.2005.04.097
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:25844505145
SN - 0021-9797
VL - 291
SP - 263
EP - 272
JO - Journal of Colloid and Interface Science
JF - Journal of Colloid and Interface Science
IS - 1
ER -