FLEXIBLE OIL SENSORS BASED ON MULTIWALLED CARBON NANOTUBE–FILLED ISOPRENE ELASTOMER COMPOSITES

2016 ◽  
Vol 89 (2) ◽  
pp. 306-315 ◽  
Author(s):  
Deepalekshmi Ponnamma ◽  
Kishor Kumar Sadasivuni ◽  
Sabu Thomas ◽  
Igor Krupa ◽  
Mariam Al-Ali AlMa'adeed

ABSTRACT Oil spills due to either accidents or deliberate oily discharges cause severe pollution and can be thwarted if proper detection facilities are applied. This article reports new flexible oil sensor capabilities of three different elastomer (natural rubber, butyl rubber, and styrene–isoprene–styrene copolymer) composites of multiwalled carbon nanotubes (MWCNTs). We highlight the sensor manufacturing by simple means of solution mixing, and the uniform dispersion of MWCNTs in the elastomers is substantiated with the help of morphology and structural analyses. Electrical percolation and semiconductor characteristics were also examined for composites. The developed materials show better oil sensing above the percolation level, and the filler–polymer interfacial interaction is the main factor regulating the oil-detecting capability. The efficiency of the sensors was also tested after many instances of bending.

2021 ◽  
Vol 11 ◽  
pp. 184798042110113
Author(s):  
Xingyao Liu ◽  
Rongxin Guo ◽  
Zhiwei Lin ◽  
Yang Yang ◽  
Haiting Xia ◽  
...  

In this article, multiwalled carbon nanotube/natural rubber composites with resistance-strain sensitivity were prepared by solution method, when the electrical percolation threshold of multiwalled carbon nanotube is only ∼3.5 wt%. The mechanical properties and resistance-strain response sensitivity were studied and analyzed systematically. The dispersion of multiwalled carbon nanotubes in the natural rubber matrix was characterized by field-emission scanning electron microscope and X-ray diffractometer. The composite exhibits good deformation sensitivity (gauge factor >27), large strain sensing range (>200%), and high signal stability when multiwalled carbon nanotube content was appropriate. The composite is suited to application in strain monitoring of large deformation structures since the resistance-strain response is more stable when strain exceeds 100%. To understand the mechanism of the resistance-strain response, the ‘shoulder peak’ of resistance-strain curve was researched and explained by the digital image correlation method, and an analytical model was developed when considering the effects of electronic tunneling and hopping in multiwalled carbon nanotube networks. Both experiment and analytical results confirm the break-restructure process of multiwalled carbon nanotube networks under applied strain cause the resistance-strain response. Finally, the practical application of the composite to monitoring strain load of rubber isolation bearing was realized.


2017 ◽  
Vol 36 (9) ◽  
pp. 685-695 ◽  
Author(s):  
ZA Ghaleb ◽  
M Mariatti ◽  
ZM Ariff

Tensile and electrical properties of graphene nanopowder (GNP) and multiwalled carbon nanotubes (MWCNT) filled epoxy thin film nanocomposites were investigated. In addition, synergy effects of various mixture ratios of GNP–MWCNT hybrids on the properties of the epoxy thin film nanocomposites were evaluated. It was found that the addition of GNPs or MWCNTs decreased the tensile properties compared to that of unfilled epoxy. The electrical percolation threshold of MWCNT/epoxy was found to be 0.8 vol%. Addition of only 0.1 vol% GNPs results in significant improvement in the electrical properties of the composites. Enhanced tensile and electrical properties in the GNP–MWCNT/epoxy hybrid were achieved with GNP–MWCNT ratio of 0.1:0.4. Morphological analysis confirmed the uniform dispersion of both GNPs and MWCNTs within the epoxy matrix. For the hybrid GNP–MWCNT filler system (i.e., with the 0.1:0.4 ratio), MWCNTs were seen to align themselves on the GNPs surfaces creating an interconnected strong nanofiller network in the epoxy.


2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Waris Obitayo ◽  
Tao Liu

The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.


2014 ◽  
Vol 38 (10) ◽  
pp. 4799-4806 ◽  
Author(s):  
Md. Shahinul Islam ◽  
Won San Choi ◽  
Tae Sung Bae ◽  
Young Boo Lee ◽  
Ha-Jin Lee

We report a simple protocol for the fabrication of multiwalled carbon nanotubes (MWCNTs) with a neuron-like structure for loading ultra-high densities of metal nanoparticles (NPs).


2003 ◽  
Vol 791 ◽  
Author(s):  
P. C. Ramamurthy ◽  
W. R. Harrell ◽  
R. V. Gregory ◽  
B. Sadanadan ◽  
A. M. Rao

ABSTRACTHigh molecular weight polyaniline / multi-walled carbon nanotube composite films were fabricated using solution processing. Composite films with various weight percentages of multiwalled carbon nanotubes were fabricated. Physical properties of these composites were analyzed by thermogravimetric analysis, tensile testing, and scanning electron microscopy. These results indicate that the addition of multiwalled nanotubes to polyaniline significantly enhances the mechanical properties of the films. In addition, metal–semiconductor (composite) (MS) contact devices were fabricated, and it was observed that the current level in the films increased with increasing multiwalled nanotube content. Furthermore, it was observed that polyaniline containing one weight percent of carbon nanotubes appears to be the most promising composition for applications in organic electronic devices.


RSC Advances ◽  
2017 ◽  
Vol 7 (33) ◽  
pp. 20422-20429 ◽  
Author(s):  
Tongfei Wu ◽  
Biqiong Chen

Viscoelastic rubber reinforced by multiwalled carbon nanotubes exhibited rapid, autonomous, mechanically and electrically self-healing properties and piezoresistive behavior.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yan He ◽  
Zhifang Cao ◽  
Lianxiang Ma

A new procedure for the fabrication of natural rubber composite with aligned carbon nanotubes is provided in this study. The two-step approach is based on (i) the preparation of mixture latex of natural rubber, multiwalled carbon nanotubes, and other components and (ii) the orientation of carbon nanotubes by a flow field. Rubber composite sheets filled with variable volume fraction of aligned carbon nanotubes were fabricated and then confirmed by transmission electron microscopy and Raman spectroscopy studies. An obvious increase in thermal conductivity has been obtained after the alignment of carbon nanotubes. The dynamic mechanical analysis was carried out in a tear mode for the composite.


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