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

Viewpoint: Superfluids Hit the Street
Atomic and Molecular Physics

Viewpoint: Superfluids Hit the Street

A flow pattern dubbed the von Kármán vortex street, which is renowned for its aesthetic beauty and extreme power, has been created in a superfluid. Read More »

Synopsis: Wetting Matters When Emptying a Tank
Fluid Dynamics

Synopsis: Wetting Matters When Emptying a Tank

The speed at which water drains out of a tank depends on the affinity of water with the outside surface of the orifice through which it drains.   Read More »

Viewpoint: An Ultrafast Switch for Electron Emission
Condensed Matter Physics

Viewpoint: An Ultrafast Switch for Electron Emission

By firing laser pulses of two different colors at a nanosized metal tip, researchers create an interference effect that turns electron emission on and off with femtosecond timing. Read More »

More Articles