Resistance of Boron Nitride Nanotubes to Radiation-Induced Oxidation.

We present unprecedented results on the damage thresholds and pathways for boron nitride nanotubes (BNNT) under the influence of energetic electrons in an oxidative gas environment, using an environmental aberration-corrected electron microscope over a range of oxygen pressures. We observe a damage cascade process that resists damage until a higher electron dose, compared with carbon nanotubes, initiating at defect-free BNNT sidewalls and proceeding through the conversion from crystalline nanotubes to amorphous boron nitride (BN), resisting oxidation throughout. We compare with prior results on the oxidation of carbon nanotubes and present a model that attributes the onset of damage in both cases to a physisorbed oxygen layer that reduces the threshold for damage onset.

Ion transport and ultra-efficient osmotic power generation in boron nitride nanotube porins.

Nanotube porins form transmembrane nanomaterial-derived scaffolds that mimic the geometry and functionality of biological membrane channels. We report synthesis, transport properties, and osmotic energy harvesting performance of another member of the nanotube porin family: boron nitride nanotube porins (BNNTPs). Cryo-transmission electron microscopy imaging, liposome transport assays, and DNA translocation experiments show that BNNTPs reconstitute into lipid membranes to form functional channels of ~2-nm diameter.

Dynamics of high-speed electrical tree growth in electron-irradiated polymethyl methacrylate.

Dielectric materials are foundational to our modern-day communications, defense, and commerce needs. Although dielectric breakdown is a primary cause of failure of these systems, we do not fully understand this process. We analyzed the dielectric breakdown channel propagation dynamics of two distinct types of electrical trees.

Environmental damping and vibrational coupling of confined fluids within isolated carbon nanotubes.

Because of their large surface areas, nanotubes and nanowires demonstrate exquisite mechanical coupling to their surroundings, promising advanced sensors and nanomechanical devices. However, this environmental sensitivity has resulted in several ambiguous observations of vibrational coupling across various experiments. Herein, we demonstrate a temperature-dependent Radial Breathing Mode (RBM) frequency in free-standing, electron-diffraction-assigned Double-Walled Carbon Nanotubes (DWNTs) that shows an unexpected and thermally reversible frequency downshift of 10 to 15%, for systems isolated in vacuum.

Carbon-Nanotube-Encapsulated-Sulfur Cathodes for Lithium-Sulfur Batteries: Integrated Computational Design and Experimental Validation.

To mitigate lithium-polysulfides (Li-PSs) shuttle in lithium-sulfur batteries (LiSBs), a unique carbon-nanotube-encapsulated-sulfur (S@CNT) cathode material with optimum open-ring sizes (ORSs) on the CNT walls were designed using an integrated computational approach followed by experimental validation. By calculating the transport barrier of Li ion through ORSs on the CNT walls and comparing the molecular size of solvents and Li-PSs with ORSs, optimum open-rings with 16-30 surrounding carbon atoms were predicted to selectively allow transportation of Li ion and evaporated sulfur while blocking both Li-PS and solvent molecules. A CNT oxidation process was proposed and simulated to generate these ORSs, and the results indicated that the optimum ORSs can be achieved by narrowly controlling the oxidation parameters.