Electrically and thermally conductive elastomer by using MXene nanosheets with interface modification

It is a challenge to compound hydrophilic MXene nanosheets with hydrophobic elastomers for various applications such as stretchable devices. In this work, Ti3C2Tx MXene nanosheets of 3.5 ± 1.0 nm in thickness were chemically modified by a facile method to enhance compatibility with a common elastomer, nitrile butadiene rubber (NBR). X-ray photoelectron spectroscopy showed the presence of nitrogen in the MXene through the modification by allylamine, whilst Raman spectroscopy revealed an increase in =O groups, exposing more reactive sites on the nanosheet surface. Fourier transform infrared spectroscopy indicated the disappearance of –C=C bonds in the nanocomposites as well as the breakage of –C≡N bonds, confirming that allylamine bridged MXene nanosheets with the matrix molecules. X-ray diffraction study showed the complete exfoliation of nanosheets in the elastomer matrix at 2.0 vol%, as confirmed by TEM micrographs. At 14.0 vol% MXene, the Young's modulus, tensile strength and thermal conductivity of NBR were improved by 700, 240 and 440%, respectively. A percolation threshold of electrical conductivity was obtained at 3.9 vol% of MXene while thermal conductivity at 19.6 vol% – 1.01 W·m−1K−1 – outperformed previous elastomer nanocomposites containing boron nitride, zinc oxide, graphene nanoplatelets and alumina.