TY - JOUR
T1 - A technique for spatially-resolved contact resistance-free electrical conductivity measurements of aligned-carbon nanotube/polymer nanocomposites
AU - Mitchell, Robert R.
AU - Yamamoto, Namiko
AU - Cebeci, Hülya
AU - Wardle, Brian L.
AU - Thompson, Carl V.
N1 - Funding Information:
The authors acknowledge support from Boeing, EADS, Embraer, Lockheed Martin, Saab AB, Composite Systems Technology, Hexcel, and TohoTenax through MIT’s Nano-Engineered Composite Aerospace Structures (NECST) Consortium. Namiko Yamamoto acknowledges the Linda and Richard (1958) Hardy Fellowship. Robert Mitchell acknowledges support from the Singapore-MIT Alliance and fruitful discussions with Jihun Oh at MIT. This work made use of the MRSEC Shared Experimental Facilities supported by the National Science Foundation under award number DMR – 0819762. This work was carried out in part through the use of MIT’s Microsystems Technology Laboratories.
PY - 2013/1/4
Y1 - 2013/1/4
N2 - The use of carbon nanotubes (CNTs) as an additive in polymer nanocomposites (PNCs) is being driven by a need to improve the mechanical, electrical, and thermal properties of composite materials for a variety of applications including advanced aerospace vehicles. The magnitude of electrical conductivity in CNT-containing PNCs is primarily influenced by the volume fraction, dispersion, interconnectivity and alignment of CNTs as well as the individual CNT properties, which are a function of diameter, chirality, and defects. Measurement techniques used to quantify the electrical conductivity of composites containing CNTs suffer from a host of issues including the influence of contact resistance, poor sample preparation leading to inadequate electrical contact of all concentric shells in aligned multi-walled CNT PNCs, and poor spatial resolution, which can obscure the micrometer- to millimeter-scale effects of inhomogeneities. In this study we demonstrate a new technique for measuring the local (∼100μm resolution) conductivity of PNCs fabricated by infusing aligned CNT arrays with a non-conductive polymer, where the CNTs are continuous through the thickness of the composite. The technique involves the use of improved surface preparation processes, prior to the formation of electrical contacts, to ensure good electrical engagement of the CNTs. Furthermore, this technique provides a systematic process to remove the contribution of contact resistance and therefore measure the conductivity of the polymer nanocomposite alone. Using this technique we have measured a conductivity of 2.2×104S/m for aligned CNTs (20% volume fraction) in RTM-6 aerospace epoxy.
AB - The use of carbon nanotubes (CNTs) as an additive in polymer nanocomposites (PNCs) is being driven by a need to improve the mechanical, electrical, and thermal properties of composite materials for a variety of applications including advanced aerospace vehicles. The magnitude of electrical conductivity in CNT-containing PNCs is primarily influenced by the volume fraction, dispersion, interconnectivity and alignment of CNTs as well as the individual CNT properties, which are a function of diameter, chirality, and defects. Measurement techniques used to quantify the electrical conductivity of composites containing CNTs suffer from a host of issues including the influence of contact resistance, poor sample preparation leading to inadequate electrical contact of all concentric shells in aligned multi-walled CNT PNCs, and poor spatial resolution, which can obscure the micrometer- to millimeter-scale effects of inhomogeneities. In this study we demonstrate a new technique for measuring the local (∼100μm resolution) conductivity of PNCs fabricated by infusing aligned CNT arrays with a non-conductive polymer, where the CNTs are continuous through the thickness of the composite. The technique involves the use of improved surface preparation processes, prior to the formation of electrical contacts, to ensure good electrical engagement of the CNTs. Furthermore, this technique provides a systematic process to remove the contribution of contact resistance and therefore measure the conductivity of the polymer nanocomposite alone. Using this technique we have measured a conductivity of 2.2×104S/m for aligned CNTs (20% volume fraction) in RTM-6 aerospace epoxy.
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U2 - 10.1016/j.compscitech.2012.11.003
DO - 10.1016/j.compscitech.2012.11.003
M3 - Article
AN - SCOPUS:84871591343
SN - 0266-3538
VL - 74
SP - 205
EP - 210
JO - Composites Science and Technology
JF - Composites Science and Technology
ER -