Journal of Polymer Science Part A: Polymer Chemistry, Vol.47, No.20, 5208-5220, 2009
Visibly Observed Photocrosslinking Reaction in Indolyl Based Pendant Liquid Crystalline Polymers: Synthesis and Optical Property
Visibly observed photocrosslinkable pendant liquid crystalline polymers containing indolyl based chalcone were synthesized by free-radical polymerization and characterized spectroscopically. The differential scanning calorimetry and polarized optical microscopy were used to examine liquid crystalline property. The photocrosslinking and luminescence properties were monitored by UV-Vis spectrophotometer and spectrofluorimeter, respectively. It demonstrates the chalcone unit did not manifest cis <-> trans-isomerization reaction along with 2 pi+2 pi photodimerization upon irradiation with UV light like other chalcones hitherto reported. The photocrosslinking was visibly monitored in solution through change of fluorescent color to colorless. The spacer lengths play a key role in the reaction. The fluorescence maximum was blue shifted around 70 nm in chloroform solution upon irradiation with UV light confirms the 2 pi+2 pi photodimerization of chalcone unit. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5208-5220, 2009
Keywords:conjugated polymers;fluorescence;indolyl based chalcone;irradiation;liquid crystalline polymers (LCP);optical property;photodimerization;photoreactive effects;resists