Effects of Graphene Nanopetal Outgrowths on Internal Thermal Interface Resistance in Composites

Thermal resistance at the interface between fiber and matrix is often the determining factor influencing thermal transport in carbon fiber composites. Despite its significance, few experimental measurements of its magnitude have been performed to date. Here, a 3ω method is applied to measure the interfacial thermal resistance between individual carbon fibers and an epoxy matrix. The method incorporates bulk and interfacial regions to extract interfacial characteristics. Measured values indicate an average thermal interface resistance of 18 mm² K/W for an interface between bare fiber and epoxy, but the average value drops to 3 mm² K/W after a microwave plasma chemical vapor deposition of two-dimensional graphene nanopetals on the carbon fiber surface

Improved Dehydrogenation Properties of Ti-Doped LiAlH₄: Role of Ti Precursors

The dehydrogenation properties of LiAlH₄ doped with different Ti precursors (Ti, TiO₂, and TiCl₃) via ball milling are investigated. The results not only show significant decreases in the decomposition temperatures (<i>T</i>_dec) and activation energies (<i>E</i>_A) of the first two dehydrogenation reaction steps of LiAlH₄ by doping with TiO₂ or TiCl₃, but also reveal how each Ti precursor affects the dehydrogenation process. Although doping LiAlH₄ with TiCl₃ induced the largest decrease in <i>T</i>_dec and <i>E</i>_A, TiO₂-doped LiAlH₄ produced a decrease in <i>T</i>_dec and <i>E</i>_A that is quite close to the TiCl₃-doped sample as well as superior short-term stability, suggesting that doping with TiO₂ has certain advantages over doping with TiCl₃. Further, the underlying mechanisms associated with the Ti precursors during the dehydrogenation reaction of LiAlH₄ have been studied using quasi in situ X-ray photoelectron spectroscopy. The results reveal that the Ti⁴⁺ and Ti³⁺ reduction processes and the segregation of Li cations to the surface of LiAlH₄ during ball milling play critical roles in the improved dehydrogenation properties observed

Effects of Carbon Nanotube-Tethered Nanosphere Density on Amperometric Biosensing: Simulation and Experiment

Nascent nanofabrication approaches are being applied to reduce electrode feature dimensions from the microscale to the nanoscale, creating biosensors that are capable of working more efficiently at the biomolecular level. The development of nanoscale biosensors has been driven largely by experimental empiricism to date. Consequently, the precise positioning of nanoscale electrode elements is typically neglected, and its impact on biosensor performance is subsequently overlooked. Herein, we present a bottom-up nanoelectrode array fabrication approach that utilizes low-density and horizontally oriented single-walled carbon nanotubes (SWCNTs) as a template for the growth and precise positioning of Pt nanospheres. We further develop a computational model to optimize the nanosphere spatial arrangement and elucidate the trade-offs among kinetics, mass transport, and charge transport in an enzymatic biosensing scenario. Optimized model variables and experimental results confirm that tightly packed Pt nanosphere/SWCNT nanobands outperform low-density Pt nanosphere/SWCNT arrays in enzymatic glucose sensing. These computational and experimental results demonstrate the profound impact of nanoparticle placement on biosensor performance. This integration of bottom-up nanoelectrode array templating with analysis-informed design produces a foundation for controlling and optimizing nanotechnology-based electrochemical biosensor performance