Multiwalled carbon nanotube hybrids derived from functionalization of amphiphilic poly(amidomine) dendrimers for improved dispersibility and electrical conductivity

Multiwalled carbon nanotubes (MWCNTs)amphiphilic poly(amidoamine) (PAMAM) dendrimers (APAMAM) based hybrids were developed through individual functionalization of PAMAM with generation 4 (G4) and generation 5 APAMAM (G5) on MWCNTs. The two hybrids were used as matrices and deposited with silver (Ag) nanoparticles (NPs) to develop another two types of new MWCNT based hybrids viz., MWCNTAPAMAM (G4)-AgNPs, and MWCNT-APAMAM (G5)AgNPs. The degree of covalent functionalization of APAMAM (G4)/(G5) in MWCNTs and deposition of AgNPs in APAMAM (G4)/(G5) were examined by Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, zeta potential, scanning and high-resolution transmission electron microscopy, and energy-dispersive spectroscopy. Further, based on the results of x-ray diffraction and high-resolution transmission electron microscopy, the size of AgNPs present in MWCNTs-APAMAM (G4)-AgNPs was determined to be in the range of 6 nm, and 2 nm for MWCNTs-APAMAM and (G5)-AgNPs respectively. The MWCNTs-APAMAM (G5) showed better dispersibility in aqueous and various polar and nonpolar organic solvents, and especially the dispersed homogeneous solution formed from water and DMSO was stable for 9 months. The MWCNTs-APAMAM (G4)/(G5)-AgNPs showed an electrical conductivity 13-19 times higher than pristine