Variation of the contact angle of drops on fibers with a previously unachieved precision and reversibility has allowed PCF members and Ciro Semprebon and Martin Brinkmann of the Max Planck Institute in Goettingen to determine the stability limits of two competing drop morphologies. Solely depending on the contact angle and drop volume relative to fiber size, a drop sitting on a fiber assumes either of the two competing morphologies: a symmetric barrel shape where the drop engulfs the fiber or an asymmetric clamshell shape where the drop sits on the side of the fiber. The numerical surface free energy calculations confirm the previously unknown metastability regime in the morphology diagram and provide a detailed picture of the energy landscape, explaining both the similarities and the differences between the barrel-to-clamshell and the reverse transition. Furthermore, the idea of manipulating the drop morphology can be evoked for designing self-rejuvenating filters. These filters can be used to separate oil-in-water emulsions more effectively.
The article has been highlighted as Inside cover and Hot article by Soft Matter.
Hot Article: Drops on functional fibers: from barrels to clamshells and back
Hüseyin Burak Eral, Jolet de Ruiter, Riëlle de Ruiter, Jung Min Oh, Ciro
Semprebon, Martin Brinkmann and Frieder Mugele, “Drops on functional fibers: from barrels to clamshells and back”Soft Matter, 2011, DOI:
10.1039/C0SM01403F (Advance Article)