Synthesis and characterization of alkyl ester functionalized multiwall carbon nanotubes.

Alkyl chains of different length were added onto surface of multiwall carbon nanotubes (MWCNT). Oxidized multiwall carbon nanotubes (MWCNT-COOH) were reacted with thionyl chloride (SOCl2) and further in esterification reaction with given alcohols gave corresponding methyl ester (MWCNT- COOCH3), n-butyl ester (MWCNT-COOC4H9) and n-dodecyl ester (MWCNT-COOC12H25) modified carbon nanotubes. Functionalization of MWCNTs was confirmed by FTIR, Raman and X-ray photoelectron spectroscopy as well as by thermogravimetric analysis.

DFT study of molecular structure and vibrations of 3-glycidoxypropyltrimethoxysilane.

Molecular structure and vibrational frequencies of 3-glycidoxypropyltrimethoxysilane (GPTMS) have been investigated by density functional theory (DFT) calculations using Becke's three-parameter exchange functional combined with Lee-Young-Parr correlation functional (B3-LYP) and standard basis set 6-311++G(d,p). In order to reveal some possible conformations of GPTMS, potential energy scan has been performed in three dihedral angles SiCCC, CCCO and OCCO. The calculations predict the existence of seven different conformations.

Conformational stability and vibrations of aminopropylsilanol molecule.

Density functional theory (DFT), using the B3-LYP/6-31G(d,p) method have been used to investigate the conformation and vibrational spectra of aminopropylsilanetriol (APST) NH2CH2CH2CH2Si(OH)3. The potential function for CCCSi torsion gives rise to two distinct conformers trans and gauche. The predicted energy of the more stable trans conformer is 337 cm-1 less than the energy of gauche conformer.