Polymers Containing Spirobifluorene Units

Stable, with an estimated half-Ufe of 5000 h. Copolymers 179 and 180 show intermediate behaviour. 

The phase behaviour of PIFs 177 and 178 resembles that of the corresponding PDAFs 89 and 90, but with higher phase-transition temperatures. Thus, the octyl polymer 177 shows two nematic phases with transition temperatures at 250 and 290 °C (reverse transitions at 270 and 140 °C), while the ethylhexyl polymer 178 has only a single nematic phase with a transition at 290 °C (220 °C for the reverse transition) [279]. 

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Title Conjugated Polymers Containing Spirobifluorene Units and Use Thereof... 

Conjugated polymers containing spirobifluorene and fluorene units,... 

Spirobifluorenes have been investigated by Salbeck [100] and found to be promising materials for use in blue LEDs, and so some effort has been made to incorporate these units into polymers (Scheme 30). As poly(diarylfluorene)s have proven to be stable blue emitters it comes as no surprise to find that polymers containing spirobifluorenes such as 66 [101] and 67 [102] also produce stable blue emission. A fluorene-spirobifluorene alternating copolymer 68 has been made and was found to give stabler emission than the fluorene homopolymer 16, but green emission was still observed upon heating in air at 150 °C [103]. 

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