CONTROLLING MORPHOLOGY OF POLYSTYRENE POLY (VINYL METHYL-ETHER) BLENDS UNDERGOING SPINODAL DECOMPOSITION PROCESS BY PHOTO-CROSS-LINKS

The morphology developing during the spinodal decomposition process of polystyrene (PS)/poly(vinyl methyl ether) (PVME) blends was successfu lly controlled by photo-crosslink reactions between PS chains. The cro sslink reaction was carried out by taking advantage of the photodimeri zation of anthracene moieties that are labeled on PS chains. Effects o f photo-crosslinks on the morphology induced by temperature-jumps (T-j ump) from the one-phase region into the spinodal region were examined under several experimental conditions such as T-jump depths and irradi ation times. It was found that the concentration fluctuations developi ng during the spinodal decomposition process were efficiently frozen u pon irradiation using a XeF excimer laser as well as a mercury (Hg) la mp. Furthermore, these ordered structures are quite stable upon anneal ing. These results demonstrate that the morphology developing during t he spinodal decomposition process can be well controlled by easily acc essible light sources such as high pressure mercury lamps. Thus the ph oto-crosslink reaction described in this work can provide the basis fo r a potential technique to design multiphase polymer materials with co ntrollable ordered structures.