Thin-film synthesis and microstructure characterization of the poly(vinyl alcohol) matrix with functionalized carbon nan
- PDF / 349,755 Bytes
- 7 Pages / 585 x 783 pts Page_size
- 77 Downloads / 216 Views
Song Xu Agilent Technologies AFM, Tempe, Arizona 85282
Andrey V. Sklyarov and Steven Hardcastle University of Wisconsin, Milwaukee, Wisconsin 53201 (Received 25 July 2006; accepted 21 March 2007)
We report on the synthesis and surface characterization of thin-film nanocomposites using functionalized single-walled carbon nanotubes (CNTs) with a diamine-terminated oligomeric poly(ethylene glycol) [poly(ethylene glycol) bis (3-aminopropyl)-terminated 1500]. The functionalized CNT samples are soluble in highly polar solvents. Their common solubility allows for the intimate mixing of the functionalized nanotubes with the matrix polymer–poly(vinyl alcohol) by dip coating and wet casting to form nanocomposite thin films. We demonstrate the alignment of the CNT bundles in the thin films that are formed without the external field forces. We present our results and discuss alignment reorientations from the characterizations of the nanocomposite thin films by using a Raman spectrometer, scanning electron microscopy, and atomic force microscopy.
I. INTRODUCTION
Carbon nanotubes (CNTs) have been of interest due to their superb mechanical, electronic, and thermal properties. The high tensile strength, flexural rigidity, and high aspect ratio make the CNTs promising candidates for use as strong fibers in the reinforcement of composite materials.1,2 CNTs have high elastic tensile strength that exceeds 1 TPa, which is many times higher than the strongest steel at a fraction of the weight.3,4 Incorporating both single-walled CNTs (SWNTs) and multiwalled CNTs (MWNTs) into polymer materials has a high potential for fabricating novel materials. However, one of the challenges in the fabrication of polymer–matrix composites containing either SWNTs or MWNTs is to obtain a uniform dispersion of CNTs within the polymer matrix.5 This is a critical step in enhancing the properties of CNT-based composites. The insolubility of the CNTs in the host resin owing to the electrostatic attraction makes CNTs tend to agglomerate when dispersed in a polymer. Such aggregations compromise the expectations of using CNTs to achieve uniformly enhanced properties. To overcome the difficulties in forming a uniform disa)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2007.0254 1872 J. Mater. Res., Vol. 22, No. 7, Jul 2007 http://journals.cambridge.org Downloaded: 30 Mar 2015
persion of CNTs into matrix materials or to increase the solubility of CNTs in the matrix solutions, it has been demonstrated that CNTs can be solubilized through chemical modification or functionalization.5–7 Furthermore, the chemical functionalization can optimize the mechanical, electrical, and thermal properties of the based composites. For example, CNT-nanocomposites demonstrated higher loading capacities, adhesion, and fracture resistance.8–15 Highly thermal and electrically conductive nanocomposites have also emerged using CNTs. By adding small quantities of CNTs to a polymer host, the thermal conductivity improves from a range of 0.1 to 1
Data Loading...
