| A series of Zn salts of acid-functionalized mesogens were mixed with poly(4-vinylpyridine) (P4VP), and their thermal and structural characteristics were investigated.; For the synthesis of the three different pro-mesogenic compounds, a n-alkyl spacer of two different lengths (n = 6 and 11) was fixed to the rigid core of 4-methoxy-4′-hydroxybiphenyl and a long alkyl spacer (n = 11) to the 4-cyano-4′-hydroxybiphenyl. The mesogen moieties were then neutralized by Zn. The polymer (P4VP) was incorporated via melt-blending of the components. This preparation process was always accompanied by a colour change from white to reddish without sample degradation, as confirmed by elemental analysis and NMR.; Greatest coordination was found (detected by FTIR principally) in mixtures with the long alkyl chain (n = 11). The length of the alkyl chain spacer also affects the thermal stability of the mixtures. It was found that the mesogen exerts a plasticizing effect on the glass transition of the polymer.; It was also found that the nature of the mesogenic end group influences the mesogenic behaviour. In the case of mixtures where pro-mesogenic moieties contain methoxy end groups, stable liquid crystalline phases were difficult to obtain. In most systems, highly ordered structures indicative of phase separation between a mesogen (a mesogen-rich) phase and a polymer (or partially complexed polymer) phase were observed. However, in the case of the 0.4 and 0.52 molar ratio LC-1,11Zn/P4VP mixtures a frozen-in liquid crystalline SmA-like structure was observed.; On the other hand, in the series of mixtures with cyanobiphenyl groups, liquid crystalline behaviour was detected in the 0.5 molar ratio mixture and identified as an SmA phase. A partially ordered (E-like) complexed structure was obtained for 0.63 molar ratio mixture. |
