Glass SCLCP

Probably the most interesting feature of SCLCPs is their ability to freeze an anisotropic alignment below the glass transition, coupled with the fluidity of the mesophase [32]. This alignment can be attained by electric, magnetic or mechanical fields. 

One of the most interesting features of SCLCPs is related to the fact that a liquid crystalline phase can be orientated and frozen by cooling it to below the glass transition temperature. It is therefore necessary to drive SCLCP systems from microscopic self-organized mesophases to macroscopic order. 

Norbornene-based and oxa-norbornene-based monomers bearing dendritic side chains, XXX and XXXI (Fig. 19), were synthesized and polymerized via ROMP with initiator 6 [83]. Based on size exclusion chromatography data, the polymerization shows hving-like character up to DP=70. H- and C-NMR-spectroscopy revealed 35% cis and 65% tram sequences. These polymers displayed enantiotropic nematic and smectic mesophases, except for DP=5. In contrast to other classes of SCLCPs, the dependence of the DP on the transition temperatirre of the polymer was very weak. Glass transition and isotropization temperatures became independent of molecular weight above a degree of polymerization of about 10. 

Very sparse dielectric studies of polysiloxane scLCPs below the glassy transition show evidence of only one relaxation process, similar to the -process in polyacrylates, with a very broad distribution of relaxation times.The temperature dependence is Arrhenius and the activation energy of 51 kJ mol matches that of the jSi-process in poly acrylates (see above). Measurements performed on the oriented smectic glass show that... 

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