Percolation network dynamicity and sheet dynamics governed viscous behavior of polydispersed graphene nanosheet suspensi
- PDF / 606,618 Bytes
- 12 Pages / 547.087 x 737.008 pts Page_size
- 60 Downloads / 182 Views
RESEARCH PAPER
Percolation network dynamicity and sheet dynamics governed viscous behavior of polydispersed graphene nanosheet suspensions Purbarun Dhar • Mohammad Hasan Dad Ansari Soujit Sen Gupta • V. Manoj Siva • T. Pradeep • Arvind Pattamatta • Sarit K. Das
•
Received: 9 August 2013 / Accepted: 22 October 2013 / Published online: 7 November 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract The viscosity of polydispersed graphene nanosheet (5 nm–1.5 lm) suspensions (GNS) and its behavior with temperature and concentration have been experimentally determined. A physical mechanism for the enhanced viscosity over the base fluids has been proposed for the polydispersed GNSs. Experimental data reveal that enhancement of viscosity for GNSs lies in between those of carbon nanotube suspensions (CNTSs) and nano-alumina suspensions, indicating the hybrid mechanism of percolation (like CNTs) and Brownian motion-assisted sheet dynamics (like alumina particles). Sheet dynamics and percolation, along with a proposed percolation network dynamicity factor, have been used to determine a dimensionally consistent analytic model to accurately determine and explain the viscosity of polydispersed GNSs. The model also provides insight into the
Purbarun Dhar and Mohammad Hasan Dad Ansari have contributed equally to this study. P. Dhar V. M. Siva A. Pattamatta S. K. Das (&) Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India e-mail: [email protected] M. H. D. Ansari Department of Mechanical Engineering, Indian Institute of Technology Patna, Patna 800013, India S. S. Gupta T. Pradeep Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
mechanisms of viscous behavior of different dilute nanoparticle suspensions. The model has been found to be in agreement with the GNS experimental data, and even for CNT (diameter 20 nm, length 10 lm) and nano-alumina (45 nm) suspensions. Keywords Graphene CNT Alumina Nanofluid Nanoparticle Viscosity Percolation Particle dynamics Modeling and simulation
Introduction Graphene, the two-dimensional (2D) allotrope of carbon, has revolutionized scientific research in the recent years. Graphene being a collective ensemble of unique properties (Geim and Novoselov 2007), it is also important to study graphene when dispersed as micro or nanosheets in a fluid medium. Since the inception of research in nanosuspensions or nanofluids (dilute suspensions of nanoparticles in a suitable base fluid), the academic community world over has studied their thermal properties in great detail. However, in-depth research into other physical properties has remained scarce as yet. One such property is the viscosity of nanosuspensions and its implications in consequent applications. Graphene nanosuspensions (GNSs) may soon emerge as the raw materials for graphene-based thin films and printed electronic devices, as fluids with tunable electric and/or thermal
123
Page 2 of 12
conductivities or as bio-nanosuspen
Data Loading...
