Dramatic reduction of the effect of nanoconfinement on the glass transition of polymer films via addition of small-molecule diluent

The reduction of the effect of nanoconfinement on the glass transition temperature T_g in polymer films was studied via addition of small-molecule diluent. The pyrene-doped polystyrene (PS) films were spin coated onto glass from toluene solutions onto NaCl infrared (IR) crystal windows, transferred to glass in a water reservoir by floating, and dried in ambient conditions for several hours prior to taking measurements. The temperature dependence of fluorescence of PS films was shown as a function of pyrene content. The results indicate that the reduction of T_g in neat PS due to nanoconfinement is suppressed by a high concentration of pyrene diluent.