A NEW NEMATIC SUSPENSION BASED ON ALL-INORGANIC POLYMER RODS

The solutions of the pseudo 1-dimensional compound Li2Mo6Se6 in N-methylformamide (NMF) previously obtained by Tarascon, Di Salvo et al. are shown to be of a liquid crystalline nature. A lyotropic nematic phase is observed with the concentration range (4.10(-2) divided-by 10(-1)) mol/l Li2Mo6Se6/NMF. The gel phase obtained by dilution with acetonitrile is also of a nematic nature. The mesophases slowly flocculate on a time scale ranging from a few hours to months. Optical microscopy and small-angle X-ray-diffraction experiments show that the lyotropic nematic solutions are suspensions of charged (Mo3Se3-)infinity needles at least 1000 angstrom long. The dispersion of the needles is such that a state of truly discrete (Mo3Se3-)infinity chains is eventually reached so that their suspensions in N-methylformamide (NMF) can be regarded as an oriented assembly of discrete conducting inorganic <<wires>>.