Dispersions of multiwalled carbon nanotubes in different nematic mesogens: The study of optical transmittance and electrical conductivity

Optical transmittance and electric conductivity were studied for dispersions of multiwall carbon nanotubes (MWCNTs) in nematic liquid crystals of four different chemical classes (cyanobiphenyls, Schiff bases, azoxy compounds, and cyclohexanecarboxylic acids). The optical transmittance data showed deep integration of MWCNTs into the orientationally ordered nematic structure. The effect observed was apparently related to interactions between the MWCNTs and mesogen matrix, which appeared to be weaker when the nematic host was formed by non-aromatic molecules. Dependences of the electrical conductivity versus applied DC voltage were noticeably different for different nematic matrices. Voltage amplification of electrical conductivity was observed at relatively higher voltages (above 10 V). The increased threshold voltages for electrohydrodynamical instability in nematics were observed in MWCNT-doped dispersions.