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Full-Text Articles in Engineering
Rupture Of Two-Dimensional Alkane Crystal, Ali Dhinojwala
Rupture Of Two-Dimensional Alkane Crystal, Ali Dhinojwala
Ali Dhinojwala
We have studied the breaking of a two-dimensional alkane crystal above the disordered melt using an oscillating bubble rheometer. Surface tension changes abruptly during the expansion and contraction cycle. We postulate that this is due to rupture of the 2D crystal at grain boundaries. The magnitude of the abrupt change in surface tension decreases with a decrease in the rate of change of bubble surface area with a power law exponent of 0.8. The interfacial area formed after rupture decreases with a decrease in rate. These results provide new insights in understanding defect-mediated rupture in confined geometry.
Confinement-Induced Ordering Of Alkanes Between An Elastomer And A Solid Surface, Ali Dhinojwala
Confinement-Induced Ordering Of Alkanes Between An Elastomer And A Solid Surface, Ali Dhinojwala
Ali Dhinojwala
We have studied the molecular structure of liquid alkanes confined between a flexible elastomeric poly(dimethyl siloxane) lens and a rigid sapphire substrate using surface-sensitive infrared-visible sum frequency generation spectroscopy. The reduction in the gauche defects suggests ordering of liquid alkanes under confinement. The cooling of confined liquid below the freezing temperature leads to crystallization with alkane molecules lying on the substrate with the symmetry axis parallel to the surface normal. This structure is very different from the bulk alkane crystals next to sapphire or air interfaces.
Synthetic Gecko Foot-Hairs From Multiwalled Carbon Nanotubes, Betul Yurdumakan, Nachiket R. Raravikar, Pulickel M. Ajayan, Ali Dhinojwala
Synthetic Gecko Foot-Hairs From Multiwalled Carbon Nanotubes, Betul Yurdumakan, Nachiket R. Raravikar, Pulickel M. Ajayan, Ali Dhinojwala
Ali Dhinojwala
We report a fabrication process for constructing polymer surfaces with multiwalled carbon nanotube hairs, with strong nanometer-level adhesion forces that are 200 times higher than those observed for gecko foot-hairs.