Jeonyoon Lee

The energy losses and geometric constraints associated with conventional curing techniques of polymeric systems motivate the study of a highly scalable out-of-oven curing method using a nanostructured resistive heater comprised of aligned carbon nanotubes (A-CNT). The experimental results indicate that, when compared to conventional oven based techniques, the use of an "out-of-oven" A-CNT integrated heater leads to orders of magnitude reductions in the energy required to process polymeric layere

Here, we quantify the electron transport properties of aligned carbon nanotube (CNT) networks as a function of the CNT length, where the electrical conductivities may be tuned by up to 10× with anisotropies exceeding 40%. Testing at elevated temperatures demonstrates that the aligned CNT networks have a negative temperature coefficient of resistance, and application of the fluctuation induced tunneling model leads to an activation energy of ≈14 meV for electron tunneling at the CNT-CNT junctions

Abstract Here, a nanomaterial with morphology‐controlled nanoscale capillaries is utilized to overcome manufacturing challenges in layered polymeric architectures. It is demonstrated that the capillary pressure from a nanoporous film replaces the need for applied pressure to manufacture void‐free layered polymeric architectures. Manufacturing of aerospace‐grade advanced carbon fiber composites is performed for the first time without utilizing pressure from an autoclave. Combined with a conductiv

Composite laminates utilizing autoclave-grade carbon fiber-reinforced plastic (CFRP) prepreg were manufactured using a polymer nanoporous network (NPN) interlayer that generates capillary pressure in lieu of pressure from an autoclave. The polymer nanofiber NPN film is integrated into the interlaminar region and is shown to eliminate voids in a vacuum-bag-only (VBO) curing process. After a preliminary investigation of the effect of NPN thickness on the interlaminar region and performance, an 8 μ

This paper considers a novel electro-thermal system combining aligned carbon nanotubes (A-CNT) as a resistive heater and bistable laminates. The use of A-CNT heaters to actuate bistable laminates is characterized in terms of steady-state shape as a function of applied voltage to the heating element and the transient response of the laminate to heating. Snap-through from one stable state to another was successfully achieved with a linear relationshiop between laminate curvature and applied voltag

Semiconductor packaging continues to reduce in thickness following the overall thinning of electronic devices such as smartphones and tablets. As the package becomes thinner, the warpage of the semiconductor package becomes more important due to the reduced bending stiffness and driven by thermal residual stresses and thermal expansion mismatch during the epoxy molding compound (EMC) curing to create the package. To address this packaging reliability issue, in this study, we developed a modified

Polymer matrix nanocomposites (PNCs) incorporating high volume fractions (Vf in excess of 10 vol %) of aligned carbon nanotubes (A-CNTs) are promising for high-performance structural composite applications leveraging texture for multifunctionality and performance-to-weight ratios. However, to enable the manufacturing of scalable structures using A-CNT PNCs, nanoscale confinement and interfacial effects due to high A-CNT content in aerospace-grade polymer matrices need to be better understood. He

The broader adoption of composite materials in next-generation aerospace architectures is currently limited by the geometrical constraints and high energy costs of traditional manufacturing techniques of PMCs such as autoclave and vacuum-bag-only oven curing techniques. Here, an in situ curing technique for PMCs using a resistive heating film comprised of an aligned carbon nanotube (A-CNT) network is presented. A carbon fiber reinforced plastic (CFRP) prepreg system is effectively cured via a si