Preparation of nanocomposites. To prepare TiO2/PS nanocomposites,
0.01 g of TiO2 nanopowder (sizeo25 nm) was added to 10 ml of tetrahydrofuran (THF) and sonicated for 30 min in ultrasonic bath
(Transsonic 460/4 37 kHz). The dispersion was mixed with 10% wt/vol
THF solution of PS (Mw¼192,000 g/mol) was agitated for 3 h. The
solvent was removed by casting of the mixture on glass Petri dishes
and drying under ambient conditions for 24 h. To improve the spatial
distribution of the particles in PS matrix, dried material was grinded
and pressed between two Kapton covered Al plates 10 10 cm2 in size
using Fontijne Presses TP 400 machine. The film forming process was
carried out by hot pressing at 170 1C and 50 kN, during 30 min
(Supporting information, Fig. S1). Neat PS films were prepared using
the same procedures and conditions.