Sensing and surface morphological properties of a poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] liquid-crystalline polymer for optoelectronic applications

The sensing properties of a poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2) polymer were investigated at different concentrations and volume percentages. The effects of the concentrations and volume percentages on the sensing parameters were investigated. The sensitivities of F8T2 were found to be 3.190, 1.434, and 0.362 dB/vol % at 290, 580, and 940 nm, respectively. The response of the F8T2 increased with increasing concentration. F8T2 exhibited good sensitivity and response behaviors. Then, the optical parameters based on the refractive indices of the F8T2 at different molarities were calculated. The dispersion energy, moment of the dielectric constant optical spectrum (M-1, M-3), oscillator strength, and contrast of the F8T2 increased with increasing molarity, whereas the average excitation energy or single-oscillator energy decreased with increasing molarity. The surface morphological properties of the F8T2 polymer film were investigated, and the roughness parameters were obtained. The F8T2 polymer could be used in the fabrication of various sensors because of the good solubility, sensitivity, and response behaviors. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41659.