Nanopatterning via pressure-induced instabilities in thin polymer films

A study was conducted to demonstrate a method of nanopatterning through pressure-induced instabilities in thin polymer films. The approach was based on the presence of residual stresses in non-annealed spin-coated polymer thin films. The fast evaporation of solvent during spin-coating led to frozen-in non-equilibrated chain conformations of the polymer, generating residual stresses within the film. Fluorinated sharp stamps, containing V-shaped lines were placed on top of a spin-coated polymer film on hexamethyldisilazane (HMDS)-treated Si wafers. The stamps were brought into contact with the polymer film surface using a pressure of 3-5 bar. Scanning electron microscopy (SEM) analysis revealed that the pattern was uniform and complete over the whole of the imprinted area, while clear narrow trenches were revealed in the insert close-up image.