Nanomechanical Properties of PEF and PEF/GNP

The nanomechanical properties of the amorphous and semicrystalline neat PEF and PEF/GNP nanocomposite materials were studied by nanoindentation testing. The nanoindentation measurements, using a dynamic ultra-microhardness tester DUH-211S (Shimadzu Co., Kyoto, Japan), were conducted using a 100 nm-radius triangular pyramid indenter tip (Berkovich-type indenter) at room temperature (23 °C). The nanoindenter was loaded onto the surface of the films until a load peak of 20 mN was reached, and this was held for 3 s. Subsequently, the nanoindenter was unloaded, leading to the value of zero. The indentation depth was recorded as a function of load and the maximum load was applied to the nanoindenter during the creep time. In this study, the basic mechanical properties that were determined were the hardness and elastic modulus of the amorphous and semicrystalline neat PEF and their PEF/GNP nanocomposite samples using the Oliver and Pharr method and previous work [59 (link),60 (link),61 (link),62 (link),63 (link),64 ,65 (link)]. The average value of ten measurements taken at different locations was used to calculate these properties. Moreover, the creep displacement was investigated during the nanoindentation testing.