My talk will have two parts: In part 1, we will address the physics of voltage generation by flow of liquids on the carbon nanotubes. New experimental results will be presented to supplement our earlier studies. The focus of the talk will be to present a new mechanism of voltage generation based on van der waals friction between the flowing liquid and confined water inside the nanotube. Molecular dynamics simulations will be presented to corroborate the model. In part 2, we will show colossal shear thickening in a very dilute suspensions of carbon nanotubes. Traditionally, the candidates for shear-thickening fluids have been dense suspensions of Brownian/non-Brownian, non-aggregating, mono-disperse spherical or rod-like particles. In contrast, we demonstrate a discontinuous shear-thickening transition on varying shear stress where the viscosity jumps sharply by four to six orders of magnitude in flocculated suspensions of multiwalled carbon nanotubes (MWNT) at very low weight fractions (approximately 0.5%). Rheo-optical observations reveal the shear-thickened state as a percolated structure of MWNT flocs spanning the system size .
Jawaharlal Nehru Centre for Advanced Scientific Research
Indo-US Science & Technology Forum
NSF - Office of International Science and Engineering
MGRN 121, Purdue University, West Lafayette, IN