PREDICTION OF CRITICAL MICELLE CONCENTRATION USING A QUANTITATIVE STRUCTURE-PROPERTY RELATIONSHIP APPROACH .1. NONIONIC SURFACTANTS

A quantitative structure-property relationship study was performed on the critical micelle concentration (cmc) of nonionic surfactants using the CODESSA program. A known correlation between the logarithm of the cmc and counts of linear alkane carbon atoms and ethoxy groups in lin ear alkyl ethoxylates was improved (R(2) = 0.996) by adding cross term s of these molecular descriptors. A general three-parameter structure- property relationship was developed for a diverse set of 77 nonionic s urfactants (R(2) = 0.984) employing topological descriptors calculated for the hydrophobic fragment of the surfactant molecule. The three de scriptors represent contributions from the size of the hydrophobic gro up, the size of the hydrophilic group, and the structural complexity o f the hydrophobic group.