Introduction of Rare-Earth Oxide Nanoparticles in CNT-Based Nanocomposites for Improved Detection of Underlying CNT Network

Joel Hubbard; Tugba Isik; Troy Y Ansell; Volkan Ortalan; Claudia Luhrs

doi:10.3390/nano11092168

Introduction of Rare-Earth Oxide Nanoparticles in CNT-Based Nanocomposites for Improved Detection of Underlying CNT Network

Nanomaterials (Basel). 2021 Aug 25;11(9):2168. doi: 10.3390/nano11092168.

Authors

Joel Hubbard¹, Tugba Isik^{2

3}, Troy Y Ansell¹, Volkan Ortalan², Claudia Luhrs¹

Affiliations

¹ Mechanical and Aerospace Engineering Department, Naval Postgraduate School, Monterey, CA 93943, USA.
² Materials Science and Engineering Department, University of Connecticut, Storrs, CT 06269, USA.
³ School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.

Abstract

Epoxy resins for adhesive and structural applications are widely employed by various industries. The introduction of high aspect ratio nanometric conductive fillers, i.e., carbon nanotubes, are well studied and are known to improve the electrical properties of the bulk material by orders of magnitude. This improved electrical conductivity has made carbon nanotube-based nanocomposites an attractive material for applications where their weight savings are at a premium. However, the analytical methods for validating carbon nanotube (CNT) nanofiller dispersion and for assuring that the properties they induce extend to the entire volume are destructive and inhibited by poor resolution between matrix and tube bundles. Herein, rare-earth oxide nanoparticles are synthesized on CNT walls for the purpose of increasing the contrast between their network and the surrounding matrix when studied by imaging techniques, alleviating these issues. The adherence of the synthesized nanoparticles to the CNT walls is documented via transmission electron microscopy. The crystalline phases generated during the various fabrication steps are determined using X-ray diffraction. Deep ultraviolet-induced fluorescence of the Eu:Y₂O₃-CNT nanostructures is verified. The impacts to nanocomposite electrical properties resulting from dopant introduction are characterized. The scanning electron microscopy imaging of CNT pulp and nanocomposites fabricated from untreated CNTs and Eu:Y₂O₃-CNTs are compared, resulting in improved contrast and detection of CNT bundles. The micro-CT scans of composites with similar results are presented for discussion.

Keywords: Eu:Y2O3; carbon nanotubes; epoxy-CNT composites; micro-CT.