Abstract
Most of the current SWNTs production today is used to process bulk composite materials and thin films for exploiting their intrinsic properties at the macroscopic scale. However, the poor control of their distribution and orientation lead to unorganized architectures and limited properties [1]. Besides mechanical properties, electrical and optical properties are the most widely studied. However, various kinds of photoluminescent (PL) nanotube-based composites can be prepared only when the tubes are well dispersed as individuals in the composites [2-4]. Indeed, contacts between nanotubes quench the PL intensity. On the other hand, contacts are required to obtain some electrically conductive materials.In this work we propose and compare different strategies to sort and control the number and nature of contacts in order to control both the PL and electrical (conductivity) properties of SWNTs-based composites [2-4]. These approaches include the control of the quantity of SWNTs, the quantity and nature of the dispersing agents used to disperse them, and their orientational order. We especially work on thin films and thin layers of polymer composites, as well as inorganic gels. Different optical spectroscopy techniques, i.e. absorption, Raman and photoluminescence spectroscopies, are used to study the dispersion and orientation of the nanotubes [2-4]. Electrical measurements are achieved using two and four point probes.[1] Michael F. L. De Volder et al. Science 339, (2013) 535[2] C. Zamora-Ledezma et al, J. Phys. Chem. C, 116 (25), (2012) 13760[3] C. Zamora-Ledezma et al, Phys. Rev. E 84, (2011) 062701[4] C. Zamora-Ledezma et al, Carbon 46, (2008) 1253-1269