ORDER-PARAMETER THEORY OF ELECTRON-SPIN-RESONANCE LINE-SHAPE - APPLICATION TO THE POTASSIUM OLEATE WATER-SYSTEM

Order parameter theories are comprehensively studied for electron spin resonance (ESR) line shapes of micellar and lamellar liquid-crystalli ne phases. Theoretical spectral analysis is performed based on a gener al two-dynamic (TD) model to test the validity of two order-parameter (OF) models. The consequence of improper use of these OP models is dis cussed in terms of the model parameters. A successful application of t he OP models is presented for the micellar and lamellar liquid-crystal line phases of the binary system potassium oleate/water (KOW). Our spe ctral simulation results reveal a concentration-independent molecular order and a continuous increase of local molecular reorientational dyn amics with increasing water content, irrespective of the phase transit ions. A comparison is made for the dynamic parameters between the KOW and oleoyllysolecithin (OlLPC)/water systems. The difference is explai ned in terms of the ratio between the headgroup area and the acyl chai n area.