Hs. Serpi et Dj. Photinos, THE INFLUENCE OF SPACER CHAIN CONFORMATIONS ON THE NEMATIC ORDERING OF MAIN-CHAIN POLYMERS, The Journal of chemical physics, 105(4), 1996, pp. 1718-1734
We present a new molecular field theory of the nematic ordering of mai
n chain polymers that allows molecular structure and conformations to
be taken explicitly into account. The theory is based on the self-cons
istency conditions which follow from the invariance of the segmental o
rder parameters with respect to translations along the contour of the
polymer. The orientational order parameters of the segments of a polye
thylene chain in a nematic medium are calculated and tested with Monte
Carlo simulation. The calculations are extended to thermotropic main
chain liquid crystalline polymers (LCPs) consisting of rodlike mesogen
ic units jointed by n-alkane spacers. The temperatures of the nematic-
isotropic phase transitions of these LCPs are evaluated for the first
time in terms of molecular structure parameters and are contrasted wit
h the temperatures calculated for the respective monomer, dimer and tr
imer compounds. (C) 1996 American Institute of Physics.