Effects of nanofiller surface structure on the properties of polymer hybrid thin films

Polymer thin films are thermally not stable, and will easily dewet from the substrate. In this study, the strategy to suppress the dewetting of polystyrene (PS) thin films by the addition of polyhedral oligomeric silsesquioxanes (POSS) as a nanofiller was proposed. The addition of cyclopentyl-substituted POSS (cPOSS) to the PS thin films led to a great inhibition of dewetting. Structural analyses revealed that cPOSS segregated on the film surface and crystallized. Neutron reflectivity measurement showed that the interfacial structure was also roughened by the addition of cPOSS. On the other hand, isobutyl-substituted POSS did not form such interface enrichment layers. This difference of the dispersion state influenced the dewetting properties of the films. The inhibition of dewettng can be attributed to the modification of surface and interface by the segregation of cPOSS.