Multiscale structure modification of composites using a novel electrophoretic deposition approach: processing, characterization and scale-up
Date
2023
Authors
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Publisher
University of Delaware
Abstract
A scalable processing technique, electrophoretic deposition, has attracted research interest in the field of composite manufacturing due to its capabilities of hybridizing nanomaterials with conventional fiber-reinforced composites. Carbon nanotubes have been one of the promising candidates for the nano-sized constituent due to their exceptional mechanical and physical properties, potentially improving the matrix or interface dominant properties and integrating multifunctionality. This dissertation seeks to obtain a fundamental understanding of the processing-structure-performance relationship of carbon nanotube-based multiscale hybrid composites fabricated by electrophoretic deposition and investigate the ability to scale-up the approach through the development of a continuous roll-to-roll pilot manufacturing line. ☐ In this research, a unique film formation mechanism of functionalized carbon nanotubes on the non-conductive fiber substrates using electrophoretic deposition is investigated via multi-length scale experiments. A novel alternating current electric field waveform as an alternative to the direct current EPD system is introduced, diversifying the ways to tailor the nanocomposite morphology and composite performance. Various processing parameters such as electrode type, dispersion concentration, and electric field strength are examined, which contribute to deposition yield kinetics. ☐ Nanoscale characterization of hierarchical composites with the infused epoxy matrix is performed, taking account of the influence of functionalizing polymer, polyethyleneimine (PEI), and the porous structure of the nanocomposites uniquely created by electrophoretic deposition. Thermal and mechanical characterizations are conducted to investigate the effect of PEI on the curing behavior and mechanical properties of epoxy systems with varying cure cycles. The localized morphology and mechanical responses of CNT-PEI/epoxy composites at the fiber-matrix interface are characterized using atomic force microscopy. ☐ On the basis of quantitative and qualitative analysis of the electrophoretic deposition system in a batch process, a roll-to-roll pilot line is constructed capable of continuously manufacturing nanostructure-coated fabrics. Multiscale composites and nanomaterial-based smart textiles have been developed as multifunctional in situ sensors. The EPD process equipped with large-scale manufacturability is expected to accelerate future applications in areas ranging from virtual health to distributed structural health monitoring systems.
Description
Keywords
Carbon nanotubes, Composite manufacturing, Electrophoretic deposition, Hierarchical composites, Scale-up