Research Summaries

Back Factors that Influence the Electrical Conductivity in CNT Composites

Fiscal Year 2017
Division Graduate School of Engineering & Applied Science
Department Mechanical & Aerospace Engineering
Investigator(s) Luhrs, Claudia C.
Sponsor Department of Defense Space (DoD)
Summary The aim of this proposal is to study carbon nanotube (CNT) - cyanide ester (CE) composites that have been found to present unexpected high values of electrical conductivity. Reaching a basic understanding of the features and mechanisms responsible for the electrical properties of CNT composites will enable their use in systems for which fine tuning of the conductivity values is paramount. Applications that could highly benefit from having composites with tailored/controllable conductivity values include space systems, sensor and actuator devices, coatings and structural components, among others.
The main goal of the proposed work is to determine which variables are responsible for the high electrical conductivity observed in CE composites at very low CNT loadings and contrast them with the conductivity of other systems, such as Epoxy Resin (ER) composites, which reach same electrical conductivity at much higher CNT loading values. Some of the variables to study include CNT loading, catalyst employed to grow the CNT, surface treatments and processing/dispersion methods employed. The impact of polymeric matrix identity and the polymer-filler interface characteristics will be also scrutinized.
In the first stage of the project, the individual components: CNTs, plain CE and ER polymers, will be analyzed to establish a baseline of features and properties. That study will be followed by the examination of CNT-ER and CNT-CE composites with diverse CNT loadings. The use of multiple characterization techniques will reveal features such as filler dimensions, distribution within the matrix, fiber alignment and chemical composition of base materials and interfaces. The samples electrical, thermal and mechanical behavior will be measured as function of CNT loading. In a second stage, the samples electrical behavior observed experimentally will be compared with percolation theory predictions to determine if the ER and CE systems have reached the percolation threshold of CNT loading or to determine if other models or mechanisms are responsible for the observed performance. CNT-Epoxy composites will be fabricated at NPS using diverse approaches to disperse the filler and determine how the manufacturing steps can influence the electrical conductivity.
Finally, mechanisms responsible for the electrical properties for each of the polymeric matrices will be proposed based on analysis of samples provided by sponsor and samples developed in house. Fabrication routes to experimentally tailor electrical properties will be suggested.
Keywords CNT Composite Electrical conductivity
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal