Review of: “Physico-Chemical Properties of Selected Anionic Cationic and Nonionic Surfactants”. N.M van Os,J.R. Haak and L.M. Rupert (Eds.). Elsevier,Amsterdam, 1993, pp. viii + 608 pages. $245.75.(ISBN 0-444-89691-0)

The phase behavior in water of pentaglycerol monostearate (C₁₈G₅) and pentaglycerol monooleate (C_18:1G₅) surfactants has been studied as a function of temperature and surfactant weight fraction, W _s . The equilibrium phases present at each composition and temperature studied were characterized by means of visual observation under normal and polarized light, differential scanning calorimetry (DSC), and X‐ray scattering, both at small (SAXS) and at wide angle (WAXS). In the temperature range 0–46°C, C₁₈G₅ presents a thermotropic α‐gel structure. However, at higher temperatures, the α‐gel phase melts and a lamellar liquid crystalline (L_α) phase is formed. The amount of water that can be solubilized by α‐gel and L_α was determined by plotting the interlayer distance, d, as a function of the reciprocal of W _s . Water is soluble in the α‐gel phase up to 21 w/w% water concentration and in the L_α phase up to 30 w/w% water concentration. At higher water concentrations, excess water appears and a dispersion of α‐gel (α‐gel+W) and lamellar liquid crystal (L_α+W) in water is formed, respectively. In contrast, C_18:1G₅ is liquid in the whole range of temperatures studied (0–100°C). While at low temperatures, C_18:1G₅ presents a L_α structure, at about 63°C L_α melts and an isotropic liquid reverse micellar solution (O_m) phase is formed. The amount of water that can be solubilized by both O_m and L_α increases with temperature.