Functionalized graphene-polyvinylidene fluoride (f-G-PVDF) nanocomposite films were synthesized using a simple solvent casting technique. The investigation demonstrates the real time strain response of f-G-PVDF nanocomposites on the macro-scale under tensile loads and the use of this nanocomposite as strain sensor. This is ascribed to the variation of electrical properties of graphene-polymer upon mechanical deformation at the nanoscale. © 2011 The Royal Society of Chemistry.

Krishnan Balasubramaniam

Department of Mechanical Engineering

Sundara Ramaprabhu

Department Of Physics

Functionalized

Macro scale

Mechanical deformation

Nano scale

REAL-TIME STRAIN

REINFORCED THERMOPLASTICS

SOLVENT CASTING

strain sensors

Tensile loads

Electric properties

Graphene

Mechanical properties

Nanocomposite films

Reinforced plastics

Sensors

Structural health monitoring

Nanocomposites

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Materials Chemistry

Graphene nanoplatelet (GNP)/poly(methyl methacrylate) (PMMA) nanocomposite solution was spray coated on a glass fibre reinforced polymer composite (GFRP) beam with different initial electrical resistance (R0). Scotch tape erosion method was used to tailor the R0 of the sensors. Beams and the sensors were characterized by computed tomography (CT) and scanning electron microscopy (SEM) respectively. The piezoresistive behaviour of these sensors was evaluated in monotonic, step and cyclic loading conditions. These spray coated sensors offered good sensitivity (38.5 times) as compared to a strain gauge. A gauge factor (GF) of 55±0.5, 70±2, and 77±1 was obtained for R0 of 1, 7 and 21 kΩ GNP layers, respectively. Sensors showed good response and stability under the step and cyclic loading conditions. The ease in the process of application coupled with good sensitivity demonstrates that the GNP/PMMA spray coated sensor can be a potential candidate for the futuristic multi-functional materials for structural health monitoring. © BME-PT.

Fulltext

Express Polymer Letters

Piezoresistive behaviour of graphene nanoplatelet (Gnp)/pmma spray coated sensors on a polymer matrix composite beam

Functionalization of carbon nanotubes (CNTs) is essential for the dispersion of CNTs in polymer matrices due to their inherence. However, conventional functional groups are insulating in nature, thereby destroying the basic structure of the CNTs and their electrical conductivity due to the harsh and long-period acid treatments. Hence, a new method of functionalization is essential. In this article, a poly(vinyliedene fluoride) (PVDF) composite comprising graphene wrapped CNTs as a conducting filler is described. A strain-gauge factor of ≈20 at low strain levels (0.1%) is with a 3 wt% graphene wrapped CNT hybrid in PVDF, which overwhelms conventional metal foil strain gauges as well as functionalized CNT or functionalized graphene based polymer composites for strain sensing. A unique type of graphene wrapping over carbon nanotubes (CNTs) is achieved by chemical vapour deposition (CVD) and the same is used to prepare polymer nanocomposite films. A better and high strain gauge factor of ≈20 is obtained with conducting graphene wrapped CNTs based PVDF composites whereas the gauge factor is ≈2 with OH/COOH-CNT based PVDF composites. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macromolecular Chemistry and Physics

Graphene-functionalized carbon nanotubes for conducting polymer nanocomposites and their improved strain sensing properties

In situ reduction of graphite oxide in polymer powder has been implemented using focused solar electromagnetic radiation. The simultaneous reduction of graphite oxide, melting of the polymer and embedding of reduced graphite oxide nanoflakes in polymer offer a new way of synthesizing conducting graphene/polymer composites. An electromechanical application of the present reduced graphite oxide-PVDF nanocomposite has been proposed with a gauge factor of 12.1. © 2012 The Royal Society of Chemistry.

Nanoscale

One-pot synthesis of conducting graphene-polymer composites and their strain sensing application

Ultrathin graphene (UG) has been prepared by exfoliation of graphite oxide by a novel technique based on focused solar radiation. Graphene based engine oil nanofluids have been prepared and their frictional characteristics (FC), antiwear (AW), and extreme pressure (EP) properties have been evaluated. The improvement in FC, AW, and EP properties of nanofluids is respectively by 80, 33, and 40% compared with base oil. The enhancement can be attributed to the nanobearing mechanism of graphene in engine oil and ultimate mechanical strength of graphene. © 2011 American Chemical Society.

ACS Applied Materials and Interfaces

Graphene-based engine oil nanofluids for tribological applications

Herein we report a novel green chemical route for the simultaneous reduction and exfoliation of metal salt-graphite oxide composites for the synthesis of metal/metal oxide nanoparticles dispersed over graphene using focused solar radiation. The one-step energy efficient technique resulted in an excellent dispersion of 3D nanoparticles over 2D graphene, paving the way for creating novel hybrid nano structures which can be useful in heterogeneous catalysis, energy and environmental applications. © 2011 The Royal Society of Chemistry.

Facile and simultaneous production of metal/metal oxide dispersed graphene nano composites by solar exfoliation

Novel foam composites comprising functionalized graphene (f-G) and polyvinylidene fluoride (PVDF) were prepared and electrical conductivity and electromagnetic interference (EMI) shielding efficiency of the composites with different mass fractions of f-G have been investigated. The electrical conductivity increases with the increase in concentration of f-G in insulating PVDF matrix. A dramatic change in the conductivity is observed from 10 -16 S · m-1 for insulating PVDF to 10-4 S · m-1 for 0.5 wt.% f-G reinforced PVDF composite, which can be attributed to high-aspect-ratio and highly conducting nature of f-G nanofiller, which forms a conductive network in the polymer. An EMI shielding effectiveness of ≈20 dB is obtained in X-band (8-12 GHz) region and 18 dB in broadband (1-8 GHz) region for 5 wt.% of f-G in foam composite. The application of conductive graphene foam composites as lightweight EMI shielding materials for X-band and broadband shielding has been demonstrated and the mechanism of EMI shielding in f-G/PVDF foam composites has been discussed. © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Macromolecular Materials and Engineering

Functionalized graphene-PVDF foam composites for EMI shielding

Novel polymer nanocomposites comprising of MnO2 nanotubes (MNTs), functionalized multiwalled carbon nanotubes (f-MWCNTs), and polyvinylidene fluoride (PVDF) were synthesized. Homogeneous distribution of f- MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy. Electrical conductivity measurements were performed on these polymer composites using four probe technique. The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m). Electromagnetic interference shielding effectiveness (EMI SE) was measured with vector network analyzer using waveguide sample holder in X-band frequency range. EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region. © 2011 Eswaraiah et al.

Nanoscale Research Letters

Inorganic nanotubes reinforced polyvinylidene fluoride composites as low-cost electromagnetic interference shielding materials

Nano Letters

Controlling Energy Gap of Bilayer Graphene by Strain

Carbon

Investigation on sensitivity of a polymer/carbon nanotube composite strain sensor

Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide

Functionalized graphene reinforced thermoplastic nanocomposites as strain sensors in structural health monitoring

Journal	Journal of Materials Chemistry
ISSN	09599428
Open Access	No