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Abstract Influence of different factors on nematic alignment and relaxation dynamics in supercooled mixture of liquid crystals E7 was investigated by means of dielectric and rheo-dielectric spectroscopy. Results show that elevated pressure or application of strong oscillatory shear aligned the nematic director parallel to the electrodes. On the other hand, if after the shear treatment a static electric field is applied an alignment of the nematic director perpendicular to the electrodes is even better than in the sample quenched and aligned by bias field without the shear treatment. Highlights • E7 mixture of nematic liquid crystals is investigated here using dielectric and rheo-dielectric spectroscopy. • At ambient pressure the nematic director is self-oriented perpendicularly to the electrodes of the capacitor. • Application of the bias field increases ordering of the mesophase. • Densification or oscillatory shear can be crucial for changing an ordering of the mesophase. • Application of high pressure or strong oscillatory shear aligned the nematic director parallel to the electrodes. [ABSTRACT FROM AUTHOR]

We have investigated the dynamics in two side-chain liquid crystalline derivatives of poly(norbornene diethylester) and their co-polymers with the semicrystalline block polyoctene by dielectric spectroscopy within the temperature range 170–433 K. The structure investigation revealed the formation of a nematic and a smectic A phase, respectively, in the Side-chain polymer liquid crystals (SC-PLC) homopolymers and the co-polymers with the shorter and longer spacers, respectively. Multiple relaxation processes were found in both the homopolymers and the co-polymers. The dynamics in the co-polymer with the longer spacer forming the smectic phase were reminiscent to the corresponding SC-PLC homopolymer, indicating strong microphase separation. However, in the co-polymer with the shorter spacer of the SC-PLC block forming the nematic phase, there was evidence for dynamic mixing between the dissimilar blocks which explains the reduced transition temperature of the SC-PLC block and the absence of crystallization of the polyoctene block. [Copyright &y& Elsevier]