MOLARİTE VE ÇÖZÜCÜNÜN SIVI-KRİSTAL POLİMERİ F8T2’NİN OPTİK PARAMETRELERİ ÜZERİNDEKİ ETKİSİ ve F8T2 FİLMİNİN YÜZEY MORFOLOJİSİ ÖZELLİKLERİ

Abstract

In this study, we investigated the surface morphology of the liquid-crystalline polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2) film by high performance atomic force microscopy and the surface roughness parameters of the F8T2 film such as; roughness average (sa), root mean square roughness (sq), surface skewness (ssk) and surface kurtosis (sku) value were obtained. Also, we reported the morphology of the cross-section (wall) and height histogtams of the F8T2 film by AFM. The positive skewness and high kurtosis of the F8T2 film are desirable to achieve low friction applications. The ratios of the sq to the sa for the F8T2 film were found to be 1.271 and 1.292. Then, we investigated in detail the optical properties of the solutions of the F8T2 polymer for different molarities and solvents. The absorbance, molar extinction coefficient (e) and mass extinction coefficient (α) values of the F8T2 polymer decrease with decreasing molarity. The average transmittance, absorption band edge, direct (Egd) and indirect (Egid) energy-gap values of refraction of the F8T2 polymer increase with decreasing molarity. The maximum absorption wavelength (λmax) of the solutions of the F8T2 for 1.200 and 0.800 µM was found to be 455 nm, while the λmax of the F8T2 polymer for DCM, THF and Chloroform solvents were found to be 447, 453 and 455 nm, respectively. The yellow light of the F8T2 polymer is emitted 586 nm. The maximum mass extinction coefficient (αmax) values at maximum molar extinction coefficient (emax) (2.246x106 and 1.736x106 Lmol-1cm-1, respectively) of the solutions of the F8T2 polymer for 1.200 and 0.800 µM were found to be 59.105 and 45.684 Lg-1cm-1, respectively, while the αmax values at emax(2.461x106, 2.371x106 and 2.246x106 Lmol-1cm-1, respectively) of the F8T2 polymer for DCM, THF and Chloroform solvents were found to be 64.763, 62.395 and 59.105 Lg-1cm-1, respectively. The Egd values (2.413 and 2.387 eV, respectively) of the F8T2 polymer for 0.800 µM and Chloroform solvent are the highest values, while the Egd values (2.220 and 2.279 eV) of the F8T2 polymer for 19.737 µM and THF solvent are the lowest values. The Egid values (2.345 and 2.305 eV, respectively) of the F8T2 polymer for 0.800 µM and Chloroform solvent are the highest values, while the Egid values (2.113 and 2.053 eV) of the F8T2 polymer for 19.737 µM and THF solvent are the lowest values. The obtained Egid values of the F8T2 polymer are more lower than that of the obtained Egd values of the F8T2 polymer. Thus, the optical band-gap of the solution of the F8T2 polymer was decreased with increasing molarity and using THF solvent among DCM, THF and Chloroform solvents