Surface modification of aligned carbon nanotube arrays for electrochemical sensing applications

Abstract

The excellent optoelectronic, mechanical, and thermal properties of carbon nanotubes have made them very attractive for a wide range of potential applications. However, many applications require the growth of aligned carbon nanotubes with surface modification. We have developed a simple pyrolytic method for large-scale production of aligned carbon nanotube arrays perpendicular to the substrate. These aligned carbon nanotube arrays can be transferred onto various substrates of particular interest (e.g., polymer films for organic optoelectronic devices) in either a patterned or non-patterned fashion. The well-aligned structure further allows us to prepare aligned coaxial nanowires by electrochemically depositing a concentric layer of an appropriate conducting polymer onto the individual aligned carbon nanotubes. This approach is particularly attractive, as it allows surface characteristics of the aligned carbon nanotubes to be tuned to meet specific requirements for particular applications while their alignment structure can be largely retained. These aligned carbon nanotubes with tunable surface characteristics are of great significance to various practical applications. In this paper, we demonstrate the use of the conducting-polymer-coated aligned carbon nanotubes for electrochemical sensing applications.

Direct Growth of Flexible Carbon Nanotube Electrodes

“…This resistance value is significantly lower than that of amorphous carbon (> 1 kX/square), which is often formed on top of CNTs during normal CVD based growth processes using inorganic iron(III) compounds. [22] The Fe content of the CL layer was measured to be <5 % using energy dispersive X-ray analysis (EDXA, data not shown) and thermogravimetric analysis (TGA, Fig. S3).…”

Carbon nanotubes – Production and industrial applications

“…The effect of the gasification depends on the type of reactant used [24]. The first growth of high quality single wall nanotubes was achieved by Smalley and coworkers [25].…”

“…Their small size with larger surface; high sensitivity, fast response and good reversibility at room temperature enable them as a gas molecule sensor [61]; enhanced electron transfer when used as electrodes in electrochemical reactions [62]; and easy protein immobilization with retention of activity as potential biosensors [62] are among some of the desirable applications. Studies have shown that surface modification performed on aligned carbon nanotubes even furthers the sensitivity of nanotube sensors [25]. The main advantage of these sensors are the nanscopic size of the nanotube sensing element and the corresponding nanoscopic size of the material required for a response [50].…”

Functionalization of vertically aligned carbon nanotubes

“…Another example is the synthesis of conducting coaxial nanowires, useful for optoelectronic and sensing applications. Aligned carbon nanotubes were coated uniformly by electrochemical deposition with an appropriate conducting polymer [126–127]. …”