Slow Down Dewetting in Polymer Films by Isocyanate-treated Graphite Oxide

Isocyanate-treated graphite oxides ( i GOs) were well-dispersed into the polystyrene (PS) thin films and formed a novel network structure. With control in fabrication, an i GOs-web layer was horizontally embedded near the surface of the films and thus formed a composite slightly doped by i GOs. This work demonstrated that the i GOs network can remarkably depress the dewetting process in the polymer matrix of the composite, while dewetting often leads to rupture of polymer films and is considered as a major practical limit in using polymeric materials above their glass transition temperatures ( T g ). Via annealing the 50–120 nm thick composite and associated neat PS films at temperatures ranging from 35 °C to 70 °C above T g , surface morphology evolution of the films was monitored by atomic force microscopy (AFM). The i GOs-doped PS exhibited excellent thermal stability, i.e. , the number of dewetting holes was greatly reduced and the long-term hole growth was fairly restricted. In contrast, the neat PS film showed serious surface fluctuation and a final rupture induced by ordinary dewetting. The method developed in this work may pave a road to reinforce thin polymer films and enhance their thermal stability, in order to meet requirements by technological advances.