Nanodiamond for Advanced Composites

V.N. Mochalin
Drexel University, US

Keywords: nanodiamond, advanced composites

Summary:

Nanodiamond powder is one of the most promising carbon nanomaterials for biomedical and composite applications [1]. Nanodiamond is made of ~5nm diameter diamond particles with large accessible surface and tailorable surface chemistry; it has unique optical, mechanical, and thermal properties; and is non-toxic. To fully exploit the potential of nanodiamond in applications such as drug delivery, biomedical imaging, and nanocomposites, attention must be paid to its purity, surface chemistry, and dispersion quality. Surface modification of nanodiamond for several composite and biomedical applications will be discussed. Covalent attachment of octadecylamine improves dispersion of nanodiamond in hydrophobic polymers, such as biodegradable poly lactic acid. Reactions of nanodiamond functional groups with polymers bring the nanocomposite design to a conceptually new level, allowing for creation of covalent nanofiller-matrix interface with designed properties. In particular, aminated nanodiamond was reacted with epoxy resin yielding a composite, in which nanodiamond particles are covalently incorporated into the polymer matrix. The effect of amino groups grafted to nanodiamond on curing chemistry of epoxy resin was analyzed and taken into consideration to achieve superior mechanical properties of the composite. Covalently bonded nanodiamond-epoxy composites showed three times higher hardness, 50% higher Young’s modulus, and two times lower creep compared to the composites in which nanodiamond was not chemically linked to the matrix. For tissue engineering scaffolds and bone surgery fixation devices, the non-toxic fluorescent nanodiamond introduced into biodegradable polymers provides increased strength, visual monitoring, enhanced biomineralization, and release of growth factors and antibiotics attached to its surface. Mochalin, V. N.; Shenderova, O.; Ho, D. Nature Nanotechnol. 2012, 7, 11-23.