Prediction on Critical Micelle Concentration of Nonionic Surfactants in Aqueous Solution: Quantitative Structure‐Property Relationship Approach

In order to predict the critical micelle concentration (cmc) of nonionic surfactants in aqueous solution, a quantitative structure‐property relationship (QSPR) was found for 77 nonionic surfactants belonging to eight series. The best‐regressed model contained four quantum‐chemical descriptors, the heat of formation (ΔH), the molecular dipole moment ( D ), the energy of the lowest unoccupied molecular orbital ( E LUMO ) and the energy of the highest occupied molecular orbital ( E HOMO ) of the surfactant molecule; two constitutional descriptors, the molecular weight of surfactant ( M ) and the number of oxygen and nitrogen atoms ( n ON ) of the hydrophilic fragment of surfactant molecule; and one topological descriptor, the Kier & Hall index of zero order ( KH 0) of the hydrophobic fragment of the surfactant. The established general QSPR between Ig(cmc) and the descriptors produced a relevant coefficient of multiple determination: R 2 = 0.986. When cross terms were considered, the corresponding best model contained five descriptors E LUMO . D , KH 0 , M and a cross term n ON · KH 0, which also produced the same coefficient as the seven‐parameter model.