Carbon nanotubes and silver nanoparticles for multifunctional conductive biopolymer composites

This article fabricates and characterizes the combination of single walled carbon nanotubes (SWCNTs) and silver nanoparticles (Ag) with a biodegradable polymer matrix. Different SWCNT amount were mixed with Ag nanoparticles and introduced in the poly(epsilon-caprolactone) (PCL) polymer matrix by solvent cast process. Nanostructure synergistic effects were evaluated in terms of morphological, electrical, dielectrical, mechanical and biological properties of binary PCL/Ag, PCL/SWCNTs and ternary PCL/Ag/SWCNTs composites. Results showed a good dispersion of nanostructures in the PCL and an increase of Young modulus with silver content in the binary systems. The PCL/Ag composites exhibited poor electrical properties, while in PCL/Ag/SWCNTs ternary films higher values of conductivity were measured compared to both binary composites. Results obtained in this research indicate that Ag particles facilitate the formation of conductive pathways in the presence of SWCNTs, they act as conductive bridges among nanotube bundles and facilitate the electron transfer. The addition of a small percentage of SWCNTs promoted significantly the electrical properties of PCL/Ag nanohybrid films. Biocompatibility of binary and ternary composites, evaluated by human mesenchymal stem cells-bone marrow derived (hBM-MSCs), suggests that the combination of Ag nanoparticles and SWCNTs with a biodegradable polymer opens new perspectives for biomedical applications. (C) 2011 Elsevier Ltd. All rights reserved.