Interaction of valine and valine radicals with single-walled carbon nanotube (5,0)

Synthesis and properties of chiral poly(ester–imide)/multiwalled carbon nanotube nanocomposites containing 4,4′-thiobis(2-tert-butyl-5-methylphenol) and s-valine amino acid moieties

Chiral poly(ester–imide) (PEI) was synthesized from N-trimellitylimido- S-valine diacid with 4,4′-thiobis(2- tert-butyl-5-methylphenol) by a direct polycondensation method. S-Valine was covalently attached to carboxylated multiwalled carbon nanotubes (MWCNTs) and effectively dispersed in an aromatic polymer as a continuous medium to prepare PEI/MWCNT nanocomposites (NCs). X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy were carried out to characterize the obtained NCs. The microstructural study of the NCs showed the homogeneous dispersion of MWCNTs throughout the polymer matrix. The results from thermal analysis indicated that the thermal stability of the NCs was improved, in comparison with that of pure PEI.

Spectroscopic studies on sidewall carboxylic acid functionalization of multi-walled carbon nanotubes with valine

The valine functionalized multi-walled carbon nanotubes (MWCNTS) were prepared and characterized by using XRD, UV-Vis, FT-IR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (002) intensity was observed for valine functionalized MWCNTs compared with oxidized MWCNTs, which is likely due to sample purification by acid washing. UV-Vis study shows the formation of valine functionalized MWCNTs. FT-IR study confirms the presence of functional groups of oxidized MWCNTs and valine functionalized MWCNTs. The ESR line shape analysis indicates that the observed EPR line shape is a Gaussian line shape. The g-values indicate that the systems are isotropic in nature. The morphology study was carried out for oxidized MWCNTs and valine functionalized MWCNTs by using SEM. The EDX spectra revealed that the high purity of oxidized MWCNTs and valine functionalized MWCNTs. The functionalization has been chosen because, functionalization of CNTs with amino acids makes them soluble and biocompatible. Thus, they have potential applications in the field of biosensors and targeted drug delivery.