Electrical conductivity of a single conducting polyaniline nanotube

Abstract

We report the electrical properties of a single conducting polyaniline nanotube measured by a standard four-terminal technique. Camphor sulfonic acid doped polyaniline nanotubes were self-assembled by a template-free method. The directly measured conductivity of the single polyaniline nanotube is very high (∼31.4 S/cm), and its temperature dependence follows the three-dimensional variable range hopping model. However, the bulk conductivity of the polyaniline nanotube pellets is much smaller than the nanotube itself (only 3.5×10−2 S/cm) and ln ρ(T) is linear in T−1/2, which is due to the large intertubular contact resistance. These results will help us to understand the conduction mechanism in conducting polymers.

Polyaniline Nanofibers Prepared by Dilute Polymerization

“…[30,31,33] As the interfiber interaction is negligible in these very dilute suspensions, the characteristics of the spectra are related to the properties of the individual nanofibers only. Furthermore, as shown earlier, [39,40] there also is significant interfiber contact resistance between the individual nanofibers produced by using surfactants, [11,12] thereby decreasing the bulk conductivity. In summary, polyaniline nanofibers were successfully synthesized for the first time using dilute polymerization, resulting in the careful control of nucleation and growth.…”

Polymer Nanofibers and Nanotubes: Charge Transport and Device Applications

“…[40] The σ(T) of a single PANi-CSA nanotube (175 nm in outer diameter) synthesized by a template-free self-assembled method was studied by a standard four-terminal technique. [20,41] The conductivity of the single PANi nanotube is found to be rather high, σ 300K ~ 31.4 S/cm. The intrinsic resistance of an individual nanotube (30 k ) was found to be much smaller than the contact resistance of crossed nanotubes (500 k ) and that of PANi nanotubes obtained by the template method.…”

A Review on Electronic Transport Properties of Individual Conducting Polymer Nanotubes and Nanowires

“…Typical SEM images of an isolated polyaniline nanotube/wire (a, b and c) and polypyrrole nanotube/wire (d), and the attached platinum microleads. (Long et al, 2003a(Long et al, & 2005b The electrical connection between the Pt microleads and the sample holder was made by highly conductive silver paste and gold wires and the electrical measurements of individual polymer nanotube/wire were carried out using a Physical Property Measurement System from Quantum Design and a Keithley 6487 picoammeter/voltage source, or a Keithley 236 source-measure unit in an Oxford helium gas flow cryostat covering a wide temperature range from 300 down to 2 K. The four-probe resistance was measured by applying a very small current in the linear part of the I-V characteristics. The two-probe resistance was determined under V bias = 0.02 V, while no rectifying behaviour has been measured in our samples.…”

“…The method used to attach Pt microleads on an isolated polymer nanotube/wire was described in previous publications (Long et al, 2003a(Long et al, & 2005b. First, polymer nanotubes/ wires were ultrasonically dispersed in ethanol for template-free prepared nanotubes/wires and in dichloromethane for template-prepared PEDOT nanowires.…”

“…A common approach was generally realized by dispersing nanotubes/wires on patterned micro-or nanoelectrodes prepared by photo-lithography, electron-beam lithography and focused-ion beam deposition, followed by the subsequent searching of nanofibers just lying on the two or four electrodes only (Kim et al, 1999;MacDiarmid et al, 2001;Park et al, 2003;Lee et al, 2004;Aleshin et al, 2004;Samitsu et al, 2005;Joo et al, 2005;Aleshin, 2006;Gence et al, 2007Gence et al, & 2008Callegari et al, 2009). Particularly, focused-ion beam assisted deposition technique has been employed to attach metal microleads on isolated www.intechopen.com A Review on Electronic Transport Properties of Individual Conducting Polymer Nanotubes and Nanowires 225 nanotubes/wires directly (Long et al, 2003a(Long et al, , 2004b(Long et al, & 2005bHuang et al, 2006;Long et al, 2006c;Duvail et al, 2007;Lu et al, 2007;Long et al, 2008aLong et al, & 2009b. There are also reports demonstrating a directed electrochemical nanowire assembly technique for the fabrication and measurement of polymer nanowire arrays between pre-patterned electrodes (Ramanathan et al, 2004).…”