Synthesis and structure-property relationships of soluble rigid-flexible copolyethers containing blue and yellow light emitting units

A series of new rigid-flexible copolyethers containing blue- and yellow-emi tting conjugated segments have been synthesized. The thermal, mechanical, a nd optical properties of the polymers are controlled by the type of the com onomers, their ratio at the preparation stage, and the length of the flexib le spacer, as well as the structure of the blue monomer in the main chain. The polyethers were characterized by viscosimetry, thermal and mechanical a nalysis, NMR, and UV-vis and luminescence spectroscopy. The polymers obtain ed are soluble in common solvents, form free-standing films either from sol ution casting or after melt pressing, and show good mechanical properties. Regardless of the excitation wavelength, the polyethers show bright-yellow photoluminescence in solution, suggesting energy transfer from the blue to the yellow unit. In the solid state, the luminescence behavior is controlle d by the monomer structure, the molar percentage of the comonomer, the leng th of the flexible spacer, and the excitation wavelength.