Microstructures and mechanical performance of polyelectrolyte/nanocrystalline TiO2 nanolayered composites
1 Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, 3-11 Wenhua Road, Shenyang, 110819, People's Republic of China
2 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016, People's Republic of China
Nanoscale Research Letters 2013, 8:44 doi:10.1186/1556-276X-8-44Published: 21 January 2013
Biological materials with hierarchically laminated structures usually exhibit a good synergy between strength and fracture toughness. Here, we show that a bio-inspired (polyelectrolyte (PE)/TiO2)4 nanolayered composite with a thickness ratio of TiO2 and amorphous PE layers of about 1.1 has been prepared successfully on Si substrates by layer-by-layer self-assembly and chemical bath deposition methods. Microstructures of the nanolayered composite were investigated by scanning electron microscopy, secondary ion mass spectroscopy, and high-resolution transmission microscopy. Mechanical performance of the composite was characterized by instrumented indentation. The composite consisting of 17.9-nm-thick nanocrystalline TiO2 and 16.4-nm-thick amorphous PE layers has a strength of about 245 MPa, which is close to that of shells, while the fracture toughness of the composite, KIC = 1.62 ± 0.30 MPa · m1/2, is evidently higher than that of the bulk TiO2. A possible strategy to build the composite at nanoscale for high mechanical performance was addressed.