Experimental results on fourier transform rheology of PBLG/m-cresol and HPC/Water liquid crystalline solutions

In this work we present, for the first time, Fourier transform rheology data of liquid crystalline solutions of poly - benzyl-l-glutamate, PBLG, in m-cresol and hydroxypropylcellulose, HPC, in water. The experimental results obtained show that, liquid crystalline polymer solutions possess an unusual behaviour in the non-linear regime, when compared with flexible polymers. For the latter, the ratio between the intensity of the third and the first harmonic, I₃/I₁ (a measurement of the nonlinear character), is an increasing function of the strain amplitude, whereas for the liquid crystalline solutions I₃/I₁ presents at least one relative maxima. We believe that this behaviour may belinked to the existence of different flow regimes (periodic), other than the shear aligning one. Future theoretical treatment is under progress in order to clarify this phenomenon.