A group of novel mesogen jacketed mesomorphic polyacetylene containing terphenyl pendent groups with varying spacer lengths ({HC C[(CH2)mOOC-terpheyl-(OC6H13)2]}n

where m=5

PHA5TP-(OC6)2; m=9

PHA9TP(OC6)2) are synthesized by polymerization using [Rh(nbd)Cl]2 catalyst

and the structures and properties of the polymers are characterized and evaluated by IR

NMR

GPC

TGA

POM

DSC

XRD

UV and PL analyses. The effects of structural variations on the thermal

mesomorphic and luminescent properties were investigated by tuning the spacer length.The results show that the terphenyl mesogens endow the monomers and their polymers with good liquid crystalline behavior

and the monomers exhibit enantiotropic smectic C phases

while the polymers possess enantiotropic smectic A phases in the heating and cooling processes.The jacket effect from terphenyl mesogenic pendants at the waist position linked to the main chain contributes to the two polymers with high thermal decomposition temperature and excellent photoluminescence

which can lose almost no weight when they were heated above 370℃ and emit strong blue light at 410 nm when they were excited by the photons of 325 nm wavelength.In comparison with PHA5TP(OC6)2

the polymer with longer flexible spacer

PHA9TP(OC6)2

exhibits better liquid crystalline behavior

stronger UV light absorption and higher photoluminescence.