Zc. Liang et al., ORDER-PARAMETER THEORY OF ELECTRON-SPIN-RESONANCE LINE-SHAPE - APPLICATION TO THE POTASSIUM OLEATE WATER-SYSTEM, Chemistry and physics of lipids, 71(1), 1994, pp. 83-94
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.