Electro-optic studies of polymers of varying flexibility in solution

By use of rectangular and reversing pulse electric birefringence techniques, the electrical properties of polymers of intermediate degrees of flexibility were studied. The effects of chain flexibility, inter actions, temperature and solvent on the electrical properties of seven selected polymers are covered. In all the cases the concentration-field dependence is exponential. There is also considerably deviation from the Kerr law as the field is increased. The Kerr constants are measured for some systems for the first time while results for others are in good agreement with similar systems studied in the past. For fairly rigid polymers the Kerr constant variation with concentrations is of the form B proportional to C-xi c where the exponent xi(c), is 2.0 for monodisperse poly(gamma-benzyl-L-glutamate) and 0.4 for polydisperse poly(n-butyl isocyanate), respectively. For the flexible coil polymers the Kerr constants varied linearly with concentration. The other electrical properties, such as the dipole moments and the polarisability anisotropies for thr systems show marked concentration and molecular weight dependence.