Inkjet printing of orientated arrays of singlewall carbon nanotubes
Résumé
Nanotube-based patterns and films have exciting potential applications in electronics and optoelectronics.
One of the key issues to optimize the electrical and optical properties of nanotube
arrays is the control of their orientation. So far, orientation of nanotubes in thin films was
achieved i) directly during CVD growth [1], ii) using liquid dispersions: by dielectrophoresis [2],
in an hydrodynamic flow [3,4], in the field of an host liquid crystal [5], by formation of a liquid
crystal in concentrated suspensions [6], or iii) by stretching composites [7]. However, versatile
and industry-compatible methods are still needed, and inkjet printing appears to be a good
candidate. Recently, Denneulin et al. reported an heterogeneous orientation of SWNT in inkjet
printed lines, with a preferential orientation parallel to the lines at the edges and perpendicular
in the sub-surface [8]. On the other hand, Beyer et al. reported an homogeneous alignment
parallel to the lines for inkjet printed SWNT, and assigned it to the formation of a nematic phase
for special printing rates [9].
Here, we present a coupled Raman/SEM study of the alignment of SWNT during inkjet printing
of aqueous suspensions as a function of temperature, nanotube concentration and printing
conditions. We report a very good alignment of the nanotubes, especially at the edges of the
printed patterns, and we discuss the contributions of hydrodynamics and thermodynamics to the
orientation.
References
[1] K. Hata et al, Science (2004), 306, 132002 ; [2] S. Shekhar et al. ACS Nano (2011), 5, 1739
; [3] C. Zamora-Ledezma et al, Nano Lett., (2008), 8 (12), 4103 ; [4] Q. Li et al, J. Phys. Chem.
B (2006), 110, 13926 ; [5] N. Ould-Moussa et al, Liq. Cryst. (2013), 40, 12 ; [6] C. Zamora-
Ledezma et al, Phys. Rev. E. (2011), 84, 062701 ; [7] C. Zamora-Ledezma et al, Phys. Rev. B.
(2009), 80, 113407 ; [8] A. Denneulin et al, Carbon (2011), 49, 2603 ; [9] S.T. Beyer et al.
Langmuir (2012), 28, 8753.
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