Two new conjugated polymers P1, P2, containing pyridine inserting poly(phenylene ethynylene)s backbone with sulfonate side chains were synthesized by Sonogashira coupling reaction. UV-Vis and fluorescence spectra were employed to study their optical properties and Cu^2＋ detection. The results indicate that polymer P1 with pyridyl group entrapped in the conjugated backbone in a certain proportion could effectively modify the rigidity of the conjugated main chain and improve the sensitivity of the Cu^2＋ detection. In methanol the fluorescence quenching efficiency of P1 by Cu^2＋ is about 222 times greater than that of model monomer PESO₃.

Key words: conjugated polymer, fluorescent quenching, signal amplification