Rheological properties of dispersions of few-layer graphite fragments in cholesterol tridecylate

The rheological properties of dispersions of few-layer graphite fragments (FLG) in mesogenic cholesterol tridecylate (X-20) have been investigated.The dispersions have potential for the use in electromechanical devices based on mesomorphic materials, in which the structure is controlled due to external influences.The rheological behavior of the dispersions with FLG concentrations of 0.005 and 0.02 wt.% was studied under oscillatory mode within a frequency range from 1 to 100 rad/s and in the temperature diapason from 65 to 90 C.It was found that the addition of FLG to the liquid crystalline matrix X-20 changes the relationship between shear viscosity and external stress, resulting in an increase in the elastic properties of the material.The addition of FLG even in concentration of 0.005 wt.% has already facilitated the expansion of the frequency range of external influences to 100 rad/s, at which the chiral structure of X-20 is preserved.Most likely, this is a consequence of the interaction of the cholesterol molecules with the surface of FLG nanoparticles.The results of this work are in accordance with the data we obtained earlier in the study of the dielectric properties of the very same dispersions.The present results indicate the possibility of controlling rheological properties of dispersions of mesogens with LGF in order to improve the performance properties of electromechanical systems based on these materials.