Synopsis: Meniscus Lithography

A feedback mechanism in an evaporating liquid produces a variety of complex yet controlled patterns.
Synopsis figure
S. H. Kang et al., Phys. Rev. Lett. (2011)

The darker periphery in the stain from spilled coffee is an example of a pattern produced by evaporation in a self-organizing system. This so-called coffee ring effect is caused by capillary flow that moves particles to the edges of the evaporating droplet.

In many systems it is difficult to control how patterns form as liquids evaporate. In particular, the capillary forces generated by the liquid menisci between individual particles are often erratic. The process is also complex; the menisci drive the pattern but, in turn, depend on how the particles themselves are organized.

In a paper published in Physical Review Letters, Sung H. Kang and colleagues at Harvard University describe a process that demonstrates long-range control in pattern formation in evaporating liquids. They work with periodic arrays of nanopillars made of epoxy with a liquid sandwiched between them. Moiré-patterned arrays are left behind after evaporation modifies the originally uniform surfaces. This dynamic feedback mechanism—arrays of pillars modify the sandwiched liquid and pattern the menisci, which in turn bend the pillars in predetermined directions—provides a promising long-range force-mediated patterning mechanism, which the authors term meniscus lithography. – Sami Mitra


Announcements

More Announcements »

Subject Areas

NanophysicsFluid Dynamics

Previous Synopsis

Next Synopsis

Quantum Information

Eve Fools Alice and Bob

Read More »

Related Articles

Synopsis: Droplet Hats
Fluid Dynamics

Synopsis: Droplet Hats

Experiments show that drops can form exotic shapes as they spread out on a surface if they are miscible with the surrounding fluid. Read More »

Synopsis: Bacteria Create Own Swim Lane
Biological Physics

Synopsis: Bacteria Create Own Swim Lane

Researchers calculate the size of a low-resistance buffer zone created by microbial organisms as they swim through the mucus lining of the stomach. Read More »

Synopsis: Internal Waves Take the Staircase Down
Fluid Dynamics

Synopsis: Internal Waves Take the Staircase Down

A theoretical study indicates that large-scale waves within the ocean can travel through “staircases” of water density, a motion that could enhance ice melting at the surface. Read More »

More Articles