Study of film formation from PS latex/TiO₂ nanocomposites; Effect of latex size and TiO₂ content

In this work, we investigated the film formation from polystyrene (PS) latex/TiO₂ nanocomposites using the steady state fluorescence (SSF) and UV–vis (UVV) techniques depending on PS particle size and TiO₂ content. The structural properties of films were characterized by scanning electron microscope (SEM). The films were prepared from pyrene (P)‐labeled PS particles (SmPS:203 nm; LgPS:382 nm) by covering them with different layers of TiO₂ by dip‐coating method and then annealed at elevated temperatures. Two film series (SmPS/TiO₂ and LgPS/TiO₂) were prepared and seven different films were studied in various TiO₂ contents for each series. Scattered (I_sc), fluorescence (I_P), and transmitted (I_tr) light intensities were measured after each annealing step to monitor the stages of film formation. Results showed that, SmPS/TiO₂ films undergo complete film formation independent of TiO₂ content. However, no film formation occurs above a certain TiO₂ content in LgPS/TiO₂ films. SEM images showed that SmPS/TiO₂ films have highly well‐ordered microporous structures with increasing TiO₂ content after extraction of PS polymer whereas LgPS/TiO2 composites show no porous structure for high TiO₂ content. Our experiments also showed that porous TiO₂ films with different sizes could be successfully prepared using this technique. POLYM. COMPOS., 35:2376–2389, 2014. © 2014 Society of Plastics Engineers