Authors: ASEF ETEMADI, BARIŞ DEMİRBAY, ŞAZİYE UĞUR
Abstract: We report the effect of graphene oxide (GO) on film formation and morphological properties of GO-doped polystyrene (PS) latex nanocomposite (PS latex/GO) films using UV-visible absorption spectroscopy and scanning electron microscopy (SEM). PS latex particles were synthesized through emulsion polymerization technique and then nanocomposite blends, each containing different concentrations of GO ranging from 0 wt% to 70 wt%, were obtained. Prepared blends were deposited on glass plates via drop-casting method and coated substrates were annealed at different temperatures between 100 °C and 250 °C. At each annealing temperature, transmitted light intensity of nanocomposite films was recorded. Void closure and Prager-Tirrell models were employed to interpret the film formation behavior. Activation energy of viscous flow (ΔH) decreased from 21.80 kcal·mol-1 to 5.91 kcal·mol-1 when the amount of GO content increased in film composition. However, activation energy of interdiffusion (ΔE) varied between 1.08 kcal·mol-1 and 6.94 kcal·mol-1 without any trend upon the addition of GO nanofillers. SEM images of films agreed well with calculated activation energies. Although the interdiffusion process of GO-doped latex films remained unaffected by added GO nanofillers, optical transparency of the films enhanced up to 92.5%, demonstrating that thermally resistant and highly transparent GO-rich nanocomposite films can be fabricated.
Keywords: Void closure, interdiffusion, polystyrene latex, graphene oxide, polymer nanocomposites, polymer physics.
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