Raquel Sainz

A soluble and highly functional polyaniline–carbon nanotube composite

A completely soluble polyaniline-multi-wall carbon nanotube (CNT–PANI) composite with drastically enhanced conductivity, improved thermal stability, and luminescent behaviour, has been synthesized. The presence of straight multi-wall carbon nanotubes during the polymerization of aniline induces the formation of a more planar conformation of polyaniline which acts as coating layer for the carbon nanotubes and leads to favourable interaction between the constituents. The polyaniline-coated multi-wall carbon nanotubes align into bundles and form a three-dimensional network in the overall composite. A highly functional carbon nanotube composite completely soluble in n-methylpyrrolidinone (NMP) exhibiting all the favourable processing and transformation possibilities of PANI has been obtained. These findings have important consequences for practical technological applications, especially for the development of opto-electronic devices.

Carbon Nanotube Effect on Polyaniline Morphology in Water Dispersible Composites

A straightforward, template-free chemical oxidative polymerization of aniline was used to prepare nanofibrillar polyaniline (nf-PANI) and a set of corresponding composites with multiwall carbon nanotubes (MWNTs). All the products showed remarkable water dispersibility since they are formed by hydrophilic particles of nanometric size. A comparative study performed on composites in a wide range of MWNT loadings has led to two main conclusions: on one hand, the presence of MWNTs affects neither the chemical structure nor the crystallinity of polyaniline. On the other hand, even small amounts of MWNTs have a significant effect on the morphology of polyaniline in composites. This effect is noticeable not only in electron microscopy images but also in the UV-vis absorbance of water dispersions and electrical conductivity behavior in the solid state. Competition between nucleation sites during polymerization is proposed as an explanation for these phenomena.

Carbon nanotube composite materials: opportunities and processing issues

Funding from the Spanish Ministry of Education and Science (MEC) and the European Regional Development Fund (ERDF) under projects MAT 2006-13167-C02-01 and -02, MAT2007-66927-C02-01, is gratefully acknowledged. M.N. acknowledges the CSIC for a postdoctoral contract (I3PDR-6-02), financed by the European Social Fund. We like to thank the European Commission for the synchrotron project at the Soft Condensed Matter A2 beamline at HASYLAB (DESY-Hamburg, I-20080056 EC).