The Gas of Long Rods as a Model for Lyotropic Liquid Crystals

Abstract

The microscopic theories which have been proposed for lyotropic liquid crystals are studied, in particular in connection with the model gas of hard rods. For sufficiently long rods most theories are equivalent to that of Onsager; for shorter rods no theory seems to have a very good claim to accuracy. The theory of Flory is shown to be untrustworthy. A series of experimental tests is proposed which would allow determination of the coefficients of the Onsager expansion; available experimental data are reviewed.