Journal ArticleDOI
Fast drop movements resulting from the phase change on a gradient surface.
TLDR
The movement of liquid drops on a surface with a radial surface tension gradient is described here and has implications for passively enhancing heat transfer in heat exchangers and heat pipes.Abstract:
The movement of liquid drops on a surface with a radial surface tension gradient is described here. When saturated steam passes over a colder hydrophobic substrate, numerous water droplets nucleate and grow by coalescence with the surrounding drops. The merging droplets exhibit two-dimensional random motion somewhat like the Brownian movements of colloidal particles. When a surface tension gradient is designed into the substrate surface, the random movements of droplets are biased toward the more wettable side of the surface. Powered by the energies of coalescence and collimated by the forces of the chemical gradient, small drops (0.1 to 0.3 millimeter) display speeds that are hundreds to thousands of times faster than those of typical Marangoni flows. This effect has implications for passively enhancing heat transfer in heat exchangers and heat pipes.read more
Citations
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Microfluidics: Fluid physics at the nanoliter scale
Todd M. Squires,Stephen R. Quake +1 more
TL;DR: A review of the physics of small volumes (nanoliters) of fluids is presented, as parametrized by a series of dimensionless numbers expressing the relative importance of various physical phenomena as mentioned in this paper.
Journal ArticleDOI
Anisotropic metal nanoparticles: Synthesis, assembly, and optical applications
Catherine J. Murphy,Tapan K. Sau,Anand Gole,Christopher J. Orendorff,Jinxin Gao,Linfeng Gou,Simona E. Hunyadi,Tan Li +7 more
TL;DR: Variations in reaction conditions and crystallographic analysis of gold nanorod have led to insight into the growth mechanism of these materials, and optical applications in sensing and imaging, which take advantage of the visible light absorption and scattering properties of the nanorods are discussed.
Journal ArticleDOI
Synthetic molecular motors and mechanical machines.
TL;DR: The exciting successes in taming molecular-level movement thus far are outlined, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion are highlighted.
Journal ArticleDOI
Directional water collection on wetted spider silk
TL;DR: Artificial fibres are designed that mimic the structural features of silk and exhibit its directional water-collecting ability by tapping into both driving forces.
Journal ArticleDOI
Artificial Molecular Machines
TL;DR: The latest generations of sophisticated synthetic molecular machine systems in which the controlled motion of subcomponents is used to perform complex tasks are discussed, paving the way to applications and the realization of a new era of “molecular nanotechnology”.
References
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Journal ArticleDOI
Wetting: statics and dynamics
TL;DR: In this paper, the authors present an attempt towards a unified picture with special emphasis on certain features of "dry spreading": (a) the final state of a spreading droplet need not be a monomolecular film; (b) the spreading drop is surrounded by a precursor film, where most of the available free energy is spent; and (c) polymer melts may slip on the solid and belong to a separate dynamical class, conceptually related to the spreading of superfluids.
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How to make water run uphill.
TL;DR: A surface having a spatial gradient in its surface free energy was capable of causing drops of water placed on it to move uphill after an imbalance in the forces due to surface tension acting on the liquid-solid contact line on the two opposite sides of the drop.
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Light-driven motion of liquids on a photoresponsive surface
TL;DR: The light-driven motion of a fluid substance in a surface-modified glass tube suggests potential applicability to microscale chemical process systems.
Journal ArticleDOI
On the motion of a small viscous droplet that wets a surface
TL;DR: In this paper, a model for the movement of a small viscous droplet on a surface is constructed that is based on the lubrication equations and uses the dynamic contact angle to describe the forces acting on the fluid at the contact line.