Single‐walled carbon nanotube silica composites obtained by an inorganic sol–gel route

Abstract

In the present work we first report on a successful incorporation of single-walled carbon nanotubes (SWCNTs) into silica matrix prepared using an inorganic sol -gel method. Through this route nonaqueous solvents are avoided and the stability of the carbon nanotubes suspensions is not affected. SWCNTs produced by Catalytic Chemical Vapor Deposition (CCVD) were dispersed in deionized water using an amphilic surfactant. As a precursor for the silica matrix an inexpensive silicic acid was used. By this route SWCNTs/silica composites were produced in the form of films and pellets. Microhardness measurements and electron microscopy suggest an important interaction between SWCNTs and the silica matrix what is important from the application point of view.

Rain erosion-resistant coatings for wind turbine blades: A review

“…Increasing the hardness of the coating makes it more durable under the impact loading by the liquid droplet, [59,38]. Andrade, et al [126], provided an economic and convenient inorganic sol-gel route to improve the hardness of the sol-gel coating by adding SWCNTs to the silica matrix. They used water as a precursor of silica and SWCNTs with an average diameter of 1.2 nm and a length of 2-4 μm as a reinforcing agent.…”

“…Raman spectroscopy of the Silica-CNTs composite film obtained by dip-coating. Reprinted from Jung de Andrade et al[126] with the permission of Wiley Inter Science Publishing. CNT: carbon nanotube.…”

Electrical conductive double-walled carbon nanotubes – Silica glass nanocomposites prepared by the sol–gel process and spark plasma sintering

“…Due to the predicted good chemical interaction of CNTs with silica matrix without altering their original properties [3,4], CNTs-SiO 2 composites have many potential applications including optical materials [5,6] or opto-electronic devices, as well as electromagnetic interference shielding devices [7,8]. Since the precursor work of Gavalas et al [9] on CNTs-silica xerogel composites, there have been several reports on CNTs-SiO 2 densified composites [5][6][7][10][11][12]. Different types of CNTs, dispersion methods and densification techniques have been used to prepare these composites.…”

“…In most cases [7,8,[10][11][12], multi-walled CNTs (MWCNTs) were preferably used probably due to their higher disponibility and lower costs in comparison to single-walled (SWCNTs) or double-walled CNTs (DWCNTs). Despite SWCNTs allowing percolation to be achieved with a lower load than MWCNTs, few studies have been dedicated to SWCNTs-SiO 2 composites [5,6]. Their functionalization would induce damage to their only wall, compromising their electronic properties.…”

“…The large surface area and high aspect ratio of CNTs associated with their high hydrophobicity makes it difficult to properly disperse them in any medium at the concentrations required for their application in composites. Therefore, various approaches to improving the dispersion of CNTs into SiO 2 have already been tested in terms of modification of the interface (by use of surfactants [5,7,8,10,11] and chemical functionalization [6]), as well as methods of composite preparation (attrition mill with colloidal SiO 2 [12] or in situ production of silica by organic [6][7][8]10,11] or inorganic [5] sol-gel routes). In addition, the incorporation of CNTs into silica glass is detrimental to densification because it slows the sintering kinetics, as any fiber does in a glass matrix [14].…”