Nanometer voids prevent crack growth in polymeric materials

Nanometer voids were introduced into polymeric materials using the CO 2 process and block copolymer template, poly(methyl methacrylate-b-perfluorooctylethyl methacrylate) (PMMA-PFMA). The thin films were etched with reactive ions to expose the embedded voids to the surface to be visualized by scanning electron microscopy. Young's modulus of the thin films were analyzed using the strain-induced elastomer buckling instability mechanical measurement (SIEBIMM). The Poisson ratios were assumed to be 0.33 and 0.5 for the film and the PDMS sheet. The SIEBIMM experiments applied on thin films with ordered nanometer voids revealed that nanometer voids have a minimum impact on the Young's modulus of the film. It was also observed that voids prevent crack growth and failure when their size is reduced to nanometers.