Thickness and Composition Dependence of the Glass Transition Temperature in Thin Homogeneous Polymer Blend Films

Nowadays there is much interest in thin polymer due to their importance in science and technology. on Tg in thin polymer films have revealed that is dependent on film thickness and that such dependence with decreasing film thickness. As the case where the interaction between the polymer the substrate is not large enough to affect the glass , Tg usually decreases with decreasing thickness. the other hand, Tg of films coated on a favorable substrate increased with decreasing thickness due to a strong interaction between and substrate. Although many experimental have been performed on Tg in typical homopolymer films, there has been no work dealing with blend systems. The concept of physically blending or more existing polymers to obtain new has been attracting widespread interest and utilization.14 This blending method can be as a good way to control the basic properties of without sacrificing many attractive properties each polymer. One of the most attractive compatible is that of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polystyrene (PS). Perhaps the most unambiguous of polymer compatibility is the detection a single glass transition temperature whose is intermediate between those corresponding the two-component polymers. For the bulk blend , PPO and PS are known to be compatible in compositions. this study, to find out the thickness dependence of depression in the compatible PPO and PS blend thin , the Tgs of the films are measured as functions of (200-1200 Å) and composition and compared