Figure 4.

Load-indentation depth curve of the composite and SEM image of the indentation-induced microcrack. (a) Load-indentation depth curve of the (PE/TiO₂)₄ nanolayered composite measured by nanoindentation. (b) SEM image showing that indentation-induced microcrack advanced into the (PE/TiO₂)₄ nanolayer-coated region, by which fracture toughness of the nanocomposite can be obtained.