Dramatic Effect of Dispersed Carbon Nanotubes on the Mechanical and Electroconductive Properties of Polymers Derived from Ionic Liquids

Abstract

Free-radical polymerization of an imidazolium ion-based ionic liquid bearing a methacrylate group, gelling with single-walled carbon nanotubes (SWNTs), allows fabrication of a mechanically reinforced, electroconductive soft material (bucky plastic). A film sample of this material displays an excellent conductivity of 1 S cm(-1) and a 120-fold enhancement of the Young's modulus at a 7 wt % content of SWNTs. The conductivity is temperature-dependent in the range 5-300 K, suggesting that the conductive process involves carrier hopping. Scanning electron and atomic force micrographs of a bucky plastic film display the presence of crosslinked networks consisting of finely dispersed SWNTs. Such nanotube networks, developed in the polymer matrix, likely suppress slipping of entrapped polymer molecules via a strong interfacial interaction and also facilitate intertubular carrier transport. Although a bucky plastic derived from a vinylimidazolium ion-based ionic liquid monomer shows a comparable conductivity to that of the methacrylate version, the film is brittle irrespective of the presence or absence of SWNTs.

Rheological behavior of multiwalled carbon nanotube-imidazolium tosylate ionic liquid dispersions

“…The procedure for the elaboration of EMIMTsO+MWCNTs dispersions consisted in the addition of MWCNTs to the ionic liquid in a 1 wt% proportion following the method described previously in [17] and also carried out in our earlier works [13,32]. The materials are weighed and mixed in an agate mortar and the resulting dispersion is manually blended for 10 minutes.…”

“…Fukushima et al have reported the preparation of CNT-IL gels, in a large scale by mechanical grinding, with applications in several fields such as sensors, actuators and electrochemistry [14,17,18]. There are several mechanisms of interaction between CNTs and ILs which can act in parallel.…”

Soft materials with graphitic nanostructures

“…We anticipated that ionic liquids of polymerizable imidazolium ions, in conjunction with SWNTs, might be good candidates for the fabrication of reinforced, electroconductive polymer materials. In fact, in situ free-radical polymerization of acrylate-and methacrylate-appended ionic liquids (figure 1), gelling with SWNTs, resulted in the formation of polymer/SWNT composite materials (bucky plastics) with highly enhanced mechanical and conductive properties ( Fukushima et al 2006). For example, a bucky plastic film, prepared from the methacrylateappended ionic liquid monomer at a 7 wt% content of SWNTs, displayed a conductivity as large as 1 S cm K1 and a 120-fold enhancement of the Young's modulus.…”

Single-walled carbon nanotubes modified by ionic liquid as antiwear additives of thermoplastics

“…The combination of ionic liquids and nanophases has given rise to new nanofluids with promising applications [27]. In particular, the ability of ionic liquids to disperse and chemically modify carbon nanotubes has raised great interest [28][29][30][31]. Imidazolium ion-based room-temperature ILs grounded with pristine single-walled carbon nanotubes (CNTs) form gels by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic liquids.…”