Nanoindentation measurements of Teflon‐AF nanosheets

We report the formation of cohesive, mechanically robust thin films of Teflon-AF formed via self-assembly of nanoparticles at both air/water and oil/water interfaces of micro-emulsion droplets. We also present results of morphological and mechanical investigations of thin films formed at these oil/water interfaces. Scanning electron microscope and low angle X-ray diffraction characterization of drop cast thin films from the micro-emulsions showed the presence of stacks of nanosheets with an average thickness of 6 nm. Atomic force microscopy (AFM) characterization put the thickness at a much lower value of around 2 nm implying that these sheets are comprised of molecular sheets of Teflon-AF. AFM characterization also indicated that these sheets are stretched molecular films comprising inter-diffused molecular chains, arranged in a regular fashion. Nanoindentation studies of these films unambiguously demonstrated the tablet sliding mechanism, similar to nacre, for dissipating applied stress. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41360.