Single-Walled Carbon Nanotubes Embedded in Oriented Polymeric Nanofibers by Electrospinning

Abstract

The electrospinning process was used successfully to embed single-walled carbon nanotubes (SWCNTs) in a poly(ethylene oxide) (PEO) matrix, forming composite nanofibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphiphilic alternating copolymer of styrene and sodium maleate. The resulting dispersions were stable, having a dark, smooth, ink-like appearance. For electrospinning, the dispersions were mixed with PEO solution in an ethanol/water mixture. The distribution and conformation of the nanotubes in the nanofibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nanotubes within the nanofibers to facilitate direct observation. Nanotube alignment within the nanofibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nanotubes were embedded in a straight and aligned form, while entangled nonseparated nanotubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electrospun nanofibers with embedded SWCNTs. This result is in pronounced distinction to the detrimental effect of incorporation of multiwalled carbon nanotubes on polymer orientation in electrospun nanofibers, as reported previously.

Utilization of poly(methyl methacrylate) – carbon nanotube and polystyrene – carbon nanotube in situ polymerized composites as masterbatches for melt mixing

“…Tensile toughness of poly(methyl methacrylate) (PMMA) increased 170% after addition of 1!wt% CNTs, which were oriented in the matrix [1]. On the other hand, electrical conductivity decreases in well-aligned CNTs [3][4][5]. In PMMA composites with 2!wt% CNTs, the nanotube alignment decreased the electrical conductivity from 10 -4 S/cm (unaligned) to 10 -10 S/cm (aligned) [4].…”

Smart Materials and Structures Based on Carbon Nanotube Composites

“…Therefore, special attention is given to the dispersion process, which is essential for successful alignment of the nanotubes by the electrospinning process. Structural analysis of the composite nanofibers in terms of the distribution and orientation of both the nanotubes and the polymer matrix has been studied (Salalha et al, 2004). (Salalha et al, 2004) …”

“…Structural analysis of the composite nanofibers in terms of the distribution and orientation of both the nanotubes and the polymer matrix has been studied (Salalha et al, 2004). (Salalha et al, 2004) …”

Techniques of aligning carbon nanotubes

“…In a much more popular variation of this technique, fibers are drawn from a viscous polymer-nanotube solution using standard fiber drawing [9][10][11][12][13] or electrospinning [14][15][16] techniques. High-quality reinforced fibers are produced, exceeding 30 m in length (see Fig.…”