Phase behavior and order in mixtures of main-chain nematic polyesters with small molecules : a combined proton and deuterium NMR study

In the mixture p-azoxyanisole (PAAd14)/[CO-Ph(CF 3 )-COO-Ph(Cl)-O-] n , the small molecule is itself nematic below 135 °C; thermal lyotropic phase behavior is observed above the clearing temperature of PAAd14. In the mixture nitrobenzene-(NBd5)-)/[OPh(Me)-N=(O)N-Ph(Me)OCO(CH 2 ) 10 CO] n , the polymer chain is inherently flexible; the nematic phase is destabilized upon additon of NBd5, and the nematic-isotropic biphase drastically broadened. Orientational order of the polymer is decreased, but the basic conformational characteristic of the chain, namely, spacer extension, is retained