Dynamics of diblock co-polymers composed from a side-chain liquid-crystalline and a crystallizable block.: A dielectric spectroscopy study

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.