Film Formation From PS/Al2O3 Nanocomposites Prepared by Dip-Drawing Method

摘要

In this study, steady state fluorescence (SSF) and UV-vis (UW) techniques were used to examine film formation from pyrene (P) labeled polystyrene (PS) latex/ Al2O3 (PS/AI2O3) composites prepared by the dip-drawing method. The effects of dip-drawing rates and dipping time in Al2O3 sol on film formation behavior and the morphology of PS/Al2O3 films were investigated. Films were prepared first by casting PS dispersion on clean glass substrates which creates a close-packed array of PS sphere (203 nm) templates. These templates were then covered with Al2O3 utilizing the dip-drawing method for various dip-drawing rates and dipping times in Al2O3 sol. The film formation of these composites was studied by annealing them at a temperature range of 100°C to 270°C and monitoring the scattered light (l_(sc)), fluorescence (l_P), and transmitted light (l_(tr)) intensities after each annealing step. The structural properties of the composite films were analyzed with a scanning electron microscope (SEM). The results demonstrated that the film formation behavior and morphology of composites depended mainly on dipping time, and no dependence on the dip-drawing rate was observed. The optical results indicated that PS/Al2O3 films undergo complete film formation independent of the dip-drawing rate and dipping time. Additionally, the film formation stages were modeled and the corresponding activation energies were determined. After completion of film formation, PS polymers were extracted to obtain porous Al2O3 thin films. Highly ordered porous structures were observed for long dipping time in Al2O3 sol but no change was observed for different dip-drawing rates, confirming the optical data.