Prediction of Critical Micelle Concentration Using a Quantitative Structure-Property Relationship Approach. 1. Nonionic Surfactants

Aquantitative structure-property relationship studywasperformedon the criticalmicelle 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 linear alkyl ethoxylates was improved (R2 ) 0.996) by adding cross terms of these molecular descriptors. A general three-parameter structure-property relationship was developed for a diverse set of 77 nonionic surfactants (R2 ) 0.984) employing topological descriptors calculated for the hydrophobic fragment of the surfactantmolecule. The three descriptors represent contributions from the size of the hydrophobic group, the size of the hydrophilic group, and the structural complexity of the hydrophobic group.