Chlorinated holey double-walled carbon nanotubes for relative humidity sensors

Abstract

a b s t r a c tA chemical procedure for modification of double walled carbon nanotubes (DWCNTs) to enhance their response to humidity was developed. The DWCNTs walls were etched by hot concentrated sulfuric acid, after what the edge carbon sites were saturated by chlorine via reaction with CCl 4 vapor. This treatment increases the dispersibility of DWCNTs in solvents, removes oxygen groups, and produces chlorine decorated holes in the outer walls. Networks of chlorinated holey DWCNTs showed a high repeatable response to humid environment and a good reversible behavior after the sensor purging by dry air. The density functional theory calculations predict enhanced polarization of the DWCNTs when they contain chlorine decorated holes in the outer walls and physisorption of H 2 O molecules near chlorine atoms. These two effects are the cause of an intense low noise signal to gaseous H 2 O and easy sensor recovery.

Molecular Dynamics simulation based investigation of possible enhancement in strength and ductility of nanocrystalline aluminum by CNT reinforcement

“…In this regard, Carbon Nanotubes (CNTs) reinforcement may play a vital role as they possess a low density (~1.2g/cm 3 ), a high tensile strength (~100 GPa), a high Young's modulus (~900 GPa) and a tensile ductility of ~20%. Moreover, CNTs already attract a lot of attention as promising materials in various fields such as sensors [12], energy applications [13], biomedical applications [14], polymer composites [15,16]. Successful attempt to exploit mechanical properties of CNT has been demonstrated enormously in the case of CNT reinforced polymer composites with improved tensile strength [17], flexural strength [18] and fatigue resistance [19,20].…”

Facile Preparation and Highly Efficient Sorption of Magnetic Composite Graphene Oxide/Fe3O4/GC for Uranium Removal

“…Then, Fe n+ (n = 2, 3) ions were formed in the above suspension by adding Fe 2+ ions because a part of Fe 2+ ions were oxidized to Fe 3+ in air by the redox reaction as shown in Eq. (2). With the hydrolysis of Fe 3+ and the addition of 30% ammonia solution the magnetic composite GO/Fe 3 O 4 /GC was obtained as expressed in Eqs.…”

A Hybrid Nanomaterial Based on Single Walled Carbon Nanotubes Cross-Linked via Axially Substituted Silicon (IV) Phthalocyanine for Chemiresistive Sensors

“…To date, a large variety of materials on the basis carbon nanotubes (CNT) has been obtained, among them ordered layers [1], nanocarbon fibers [2,3], bucky paper [4,5], modified electrodes [6][7][8][9], gas or cation absorbers [10,11] and some others [12]. Pristine carbon materials can be modified by various ways, e.g., through heteroatom doping [13], covalent attachment of different atoms [14][15][16], functional groups [17][18][19][20] or molecules [21,22] as well as by non-covalent adsorption of various polyaromatic molecules [23][24][25][26], nanoparticles [4,27] or polymers [28]. One of the practical aspects of such hybrid materials is their use as the active layers of chemiresistive gas sensors.…”