Electron paramagnetic resonance study of the physical gelation of a copper complex in cyclohexane

2014 The dynamical behaviour and gelation kinetics of a copper complex substituted by eight paraffinic chains in cyclohexane has been investigated by X-band and Q-band Electron Paramagnetic Resonance spectroscopy. In the fluid-phase the complex exhibits a hyperfine structure, the anisotropy of which allows an estimate of the tumbling correlation time of the order of 4 x 10-10 s. In the gel-phase, the electron exchange between stacked complexes averages out the hyperfine structure, and the frequency dependence of the g tensor anisotropy is analysed in terms of a reduction of the tumbling rate to 03C4 ~ 8 10-9 s. The time dependence of the EPR signal provides a simple method to study the kinetics of segregation and gelation. J. Physique 48 (1987) 663-671 AVRIL 1987,