Elucidating How Surface Functionalization of Multiwalled Carbon Nanotube Affects Nanostructured MWCNT/Titania Hybrid Materials

Abstract

The new class of multiwalled carbon nanotube (MWCNT)/titania nanocomposites was prepared using a sol-gel technique. The addition of titania to MWCNTs has the potential to provide new capability for the development of electrical devices by taking advantage of the favorable electric characteristics of MWCNTs. MWCNTs were first functionalized with carboxyl, acyl chloride, amine, and hydroxyl groups and were then dispersed in a tetraisopropyl titanate (TIPT) solution via ultrasonic processing. After gelation, well-dispersed titania in the MWCNT/titania nanocomposites was obtained. Functionalized MWCNTs with varied functional groups were proved by Fourier transform infrared spectroscopy (FT-IR). For the nanocomposites, the degree of the sol-gel process were proved by Raman spectroscopy and wide-angle X-ray diffraction (WAXD). Furthermore, the morphology of the MWCNT/titania nanocomposites was observed using transmission electron microscopy (TEM). In the sol-gel process, the functionalized MWCNTs with carboxyl, acyl chloride, amine, and hydroxyl groups have resulted in the carbon nanotube-graft-titania nanocomposites with a network structure of titania between the carbon nanotubes.

Synthesis and Properties of Carbon Nanotube-Grafted Silica Nanoarchitecture-Reinforced Poly(Lactic Acid)

“…PLA was purchased from SUPLA Material Technology Ltd. (SUPLA 135N, M n = 52,000 g/mol, Tainan, Taiwan) and the MWCNTs (Baytubes C150 HP) were purchased from BASF (Ludwigshafen, Germany). The development of functionalized MWCNTs using carboxylic acid, acyl chloride, amine, and hydroxyl groups was reported in our previous study [ 7 ]. Treating MWCNTs with carboxylic acid modifies their surface through the covalent attachment of organic acid to their π-conjugated skeletons.…”

“…Later, the acyl-chloride-functionalized MWCNTs were reacted with hexamethylene diamine in tetrahydrofuran (THF) at 50 °C for 12 h; similarly, amine-functionalized MWCNTs were synthesized, and the products were washed with THF to remove unreacted chemicals. Finally, the surface-functionalized MWCNTs were dried in a vacuum oven at 50 °C for 12 h [ 6 , 7 ].…”

“…Due to the combination of their electrical, thermal, and mechanical properties, research interest in the potential applications of CNTs in composites, electronics, computers, hydrogen storage, medicine efficiency, sensors, and other technologies and tools has grown rapidly [ 3 , 4 ]. Recently, nanohybrids that contain both CNTs and functional particles have attracted particular interest because of the development of CNT chemical modification methods and the search for novel functional materials [ 5 , 6 , 7 ].…”

“…The influence of synthetic conditions, such as the applied metal alkoxide concentration, pH, temperature, catalyst morphology, and inorganic metal oxide structure, has been thoroughly studied in recent decades [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. In our own earlier research [ 7 ], we examined tetraisopropyl titanate (TIPT), a metal alkoxide that underwent various hydrolysis and polycondensation reactions and formed a network of titanium oxide bonds. Additionally, functionalized multi-walled CNTs (MWCNTs) with organic functionalized groups have been used to form CNT-grafted titania nanohybrids with a network structure of titania between the CNTs [ 7 , 21 , 22 ].…”

“…In our own earlier research [ 7 ], we examined tetraisopropyl titanate (TIPT), a metal alkoxide that underwent various hydrolysis and polycondensation reactions and formed a network of titanium oxide bonds. Additionally, functionalized multi-walled CNTs (MWCNTs) with organic functionalized groups have been used to form CNT-grafted titania nanohybrids with a network structure of titania between the CNTs [ 7 , 21 , 22 ].…”