Nematic Ordering Problem As Polymer Excluded Volume One

The new method of the mean-field approximation is extended. An approach which enables to estimate some parameters of the transition from the isotropic state of hard sticks to the nematic ordering phase is suggested. An technique of the investigation of the model jointed to the so-called polymer excluded volume problem is proposed. The critical exponents are estimated. The transition of a swelling polymer coil to ideal is revealed as the polymerization degree of the chain increases. The entanglement concentration obtained is in accordance with experimental data for polymers with flexible chains. The number of monomers between neighbor entanglements assumes to be the ratio of the stick length to its diameter. The comparison of the theory with other ones and recent experimental data is carried out.