Torsional fracture of viscoelastic liquid bridges

San To Chan, Frank P.A. van Berlo, Hammad A. Faizi, Atsushi Matsumoto, Simon J. Haward, Patrick D. Anderson, Amy Q. Shen

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Short liquid bridges are stable under the action of surface tension. In applications like electronic packaging, food engineering, and additive manufacturing, this poses challenges to the clean and fast dispensing of viscoelastic fluids. Here, we investigate how viscoelastic liquid bridges can be destabilized by torsion. By combining high-speed imaging and numerical simulation, we show that concave surfaces of liquid bridges can localize shear, in turn localizing normal stresses and making the surface more concave. Such positive feedback creates an indent, which propagates toward the center and leads to breakup of the liquid bridge. The indent formation mechanism closely resembles edge fracture, an often undesired viscoelastic flow instability characterized by the sudden indentation of the fluid’s free surface when the fluid is subjected to shear. By applying torsion, even short, capillary stable liquid bridges can be broken in the order of 1 s. This may lead to the development of dispensing protocols that reduce substrate contamination by the satellite droplets and long capillary tails formed by capillary retraction, which is the current mainstream industrial method for destabilizing viscoelastic liquid bridges.

Original languageEnglish (US)
Article numbere2104790118
JournalProceedings of the National Academy of Sciences of the United States of America
Volume118
Issue number24
DOIs
StatePublished - Jun 15 2021

Keywords

  • Contact printing
  • Edge fracture
  • Flow instability
  • Liquid bridge
  • Viscoelasticity

ASJC Scopus subject areas

  • General

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