Carbon nanotube survivability in marine environments and method for biofouling removal.

The deep sea survivability and biofouling characteristics of corrosion-resistant bulk carbon nanotubes (CNTs) have been studied after deployment in the Atlantic Ocean over the course of 12 months. Quantification of barnacle count, biofouling density, and non-combustible residue shows cyanoacrylate coatings increase durability and reduce the colonization of biofouling compared to as-received CNTs. Scanning electron microscopy was performed on the biofouled CNTs, and the majority of species were identified as diatoms, consisting of an ordered silica cell wall.

Removal of sodium dodecyl sulfate surfactant from aqueous dispersions of single-wall carbon nanotubes.

A reagent-based treatment method was developed for the removal of sodium dodecyl sulfate (SDS) from aqueous dispersions of single-wall carbon nanotubes (SWCNTs). Based on a survey of various reagents, organic solvents emerged as the most effective at interrupting the SDS:SWCNT interaction without producing deleterious side reactions or causing precipitation of the surfactant. Specifically, treatment with acetone or acetonitrile allows for the facile isolation of SWCNTs with near complete removal of SDS through vacuum filtration, resulting in a 100x reduction in processing time.

Modification of Silver/Single-Wall Carbon Nanotube Electrical Contact Interfaces via Ion Irradiation.

Introduction of defects via ion irradiation ex situ to modify silver/single-wall carbon nanotube (Ag-SWCNT) electrical contacts and the resulting changes in the electrical properties were studied. Two test samples were fabricated by depositing 0.1 μm Ag onto SWCNT thin films with average thicknesses of 10 and 60 nm, followed by ion irradiation (150 keV B at 5 × 10 ions/cm).

Carbon Nanotube Thin-Film Antennas.

Multiwalled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) dipole antennas have been successfully designed, fabricated, and tested. Antennas of varying lengths were fabricated using flexible bulk MWCNT sheet material and evaluated to confirm the validity of a full-wave antenna design equation. The ∼20× improvement in electrical conductivity provided by chemically doped SWCNT thin films over MWCNT sheets presents an opportunity for the fabrication of thin-film antennas, leading to potentially simplified system integration and optical transparency.

Enhanced Electrical Conductivity in Extruded Single-Wall Carbon Nanotube Wires from Modified Coagulation Parameters and Mechanical Processing.

Single-wall carbon nanotubes (SWCNTs) synthesized via laser vaporization have been dispersed using chlorosulfonic acid (CSA) and extruded under varying coagulation conditions to fabricate multifunctional wires. The use of high purity SWCNT material based upon established purification methods yields wires with highly aligned nanoscale morphology and an over 4× improvement in electrical conductivity over as-produced SWCNT material. A series of eight liquids have been evaluated for use as a coagulant bath, and each coagulant yielded unique wire morphology based on its interaction with the SWCNT-CSA dispersion.