Dry sonication process for preparation of hybrid structures based on graphene and carbon nanotubes usable for chemical sensors

Abstract

The combination of graphene (G) and multi-walled carbon nanotubes (MWCNTs) creates three-dimensional hybrid structures particularly suitable as next-generation electrical interface materials. Nevertheless, efficient mixing of the nanopowders is challenging, unless previous disaggregation and eventual surface modification of both is reached. To avoid use of solvents and multistep purification process for synthesis of stable G/MWCNTs hybrids, herein, a novel dry method based on an air sonication process was used. Taking advantage from the vigorous turbulent currents generated by powerful ultrasonication in air that induces strong thermal convection or radiation to and from the particles, it simultaneously ensures disentanglement of the large MWCNT bundles and G exfoliation and their only mild surface modifications. By changing the ratio between MWCNTs and G, a range of hybrids was obtained, different in surface morphology and chemistry. These hybrids have shown great potential as sensing material for designing mass-based sensors for toxic gases and chemiresistor for vapors detection.

Waterborne polymer composites containing hybrid graphene/carbon nanotube filler: Effect of graphene type on properties and performance

“…The G/CNT hybrids in three different weight ratios (G:CNT of 10:1; 1:1; and 1:10) were prepared following procedures explained elsewhere. 5,6 Shortly, graphene and CNT in suitable amounts (Table S1) were sonicated (Branson 450 instrument, Danbury, CT) in air according the following parameters: 70% of power output and 50% duty cycle for 90 min efficient time, under continuous stirring with magnetic stirrer of 200 rpm.…”

“…In these hybrid structures, the G and CNTs are connected by π–π interactions, and have shown to improve electrical, mechanical and thermal properties, in addition to the mutual stabilizing effects. These effects diminish the tendency of the carbon nanomaterial to form aggregates, and improve the dispersion of the filler within the polymer matrix 5–10 . Such composites made of hybrid G/CNT filler have shown to provide to the composite novel characteristics and to widen their application potential.…”

“…These effects diminish the tendency of the carbon nanomaterial to form aggregates, and improve the dispersion of the filler within the polymer matrix. [5][6][7][8][9][10] Such composites made of hybrid G/CNT filler have shown to provide to the composite novel characteristics and to widen their application potential. For example, the improved charge transfer process within the G/CNT hybrids improved the photostability of (meth)acrylic waterborne composites up to 400 h at accelerated aging conditions.…”

“…One strategy to overcome these challenges might be to mix G and CNTs prior to their addition to the polymer to form three-dimensional network within the polymer matrix. 5,6 In these hybrid structures, the G and CNTs are connected by π-π interactions, and have shown to improve electrical, mechanical and thermal properties, in addition to the mutual stabilizing effects. These effects diminish the tendency of the carbon nanomaterial to form aggregates, and improve the dispersion of the filler within the polymer matrix.…”

Wearable Sensors for Healthcare: Fabrication to Application

“…Similar to polymers, certain types of nanomaterials, such as carbon-based allotropes [ 42 , 43 , 44 ] and metallic nanomaterials [ 45 , 46 , 47 ], have been used as processed materials to form sensors. The carbon allotropes include Carbon Nanotubes (CNTs) [ 48 , 49 , 50 ], graphene [ 51 , 52 , 53 ], and graphite [ 54 , 55 , 56 ], while some of the types of metallic nanomaterials are nanoparticles [ 57 , 58 ], nanoribbons [ 59 , 60 ], and nano-beads [ 61 , 62 ].…”