The emission color of fluorene-based polymers can be facilely tuned across the whole visible spectrum by copolymerization with perylene dyes. Methods are demonstrated for incorporation of the dyes in the polymer mainchain, at the chain termini, or as side chains. Efficient energy transfer causes the emission to come solely from the dye units. Efficient LEDs have been made from the copolymers with dyes in the mainchain.

Binary polymer blends of hydrophobic poly(vinylidene fluoride) (PVDF) and hydrophilic poly(vinylpyrrolidone) (PVP) were prepared by melt blending.The crystallization behavior, mechanical properties and hydrophilicity of the binary blends were investigated using Fourier transform infrared spec troscopy (FTIR), wide angle X ray diffractometry (WAXD), differential scanning calorimeter (DSC) scan ning, non isothermal crystallization kinetics, successive self nucleation and annealing (SSA) fractionation, tensile tests and contact angle tests. The analysis of FTIR, WAXD, DSC scanning, non isothermal crystalli zation kinetics and SSA fractionation showed that the addition of PVP greatly influenced the crystallization behavior of the sample. As the PVP content increased, the crystallization temperature, crystallization rate, degree of crystallinity, and the amount of thick lamellaes decreased gradually. Meanwhile, PVP favored the formation of β phase of PVDF. The results of tensile test revealed that the addition of PVP increased the elon gation at break of the sample, and lowered the yield stress. Besides, the result of contact angle test indicated that the hydrophilicity of PVDF was remarkably improved in the presence PVP. The relationship between crystallization behavior and the tensile behavior, hydrophilicity were discussed.