Layer substituted mesogens

Spurred on by discussions on whether the smectic layers of the fluorocarbon-substituted polymers XXIII-m-n are induced by the immiscibility between hydrocarbon and fluorocarbon segments or by the fact that fluorocarbon segments form rod-like mesogenic units by themselves, Pugh et al. synthesized a series of siloxane-terminated monomers XXIV-m-n, with m=l,2 and n=4-S [79]. In these monomers, the rigid fluorocarbon segment was replaced by short polydimethylsiloxane (PDMS) segments that are also immiscible with hydrocarbons but are very flexible (Fig. 15). 

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