Generation of inkjet droplet of non-Newtonian fluid

Hansol Yoo, Chongyoup Kim

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


In this study, the generation of inkjet droplets of xanthan gum solutions in water-glycerin mixtures was investigated experimentally to understand the jetting and drop generation mechanisms of rheologically complex fluids using a drop-on-demand inkjet system based on a piezoelectric nozzle head. The ejected volume and velocity of droplet were measured while varying the wave form of bipolar shape to the piezoelectric inkjet head, and the effects of the rheological properties were examined. The shear properties of xanthan gum solutions were characterized for wide ranges of shear rate and frequency by using the diffusive wave spectroscopy microrheological method as well as the conventional rotational rheometry. The extensional properties were measured with the capillary breakup method. The result shows that drop generation process consists of two independent processes of ejection and detachment. The ejection process is found to be controlled primarily by high or infinite shear viscosity. Elasticity can affect the flow through the converging section of inkjet nozzle even though the effect may not be strong. The detachment process is controlled by extensional viscosity. Due to the strain hardening of polymers, the extensional viscosity becomes orders of magnitude larger than the Trouton viscosities based on the zero and infinite shear viscosities. The large extensional stress retards the extension of ligament, and hence the stress lowers the flight speed of the ligament head. The viscoelastic properties at the high-frequency regime do not appear to be directly related to the drop generation process even though it can affect the extensional properties.

Original languageEnglish
Pages (from-to)313-325
Number of pages13
JournalRheologica Acta
Issue number4
Publication statusPublished - 2013 Apr

Bibliographical note

Funding Information:
This work was partially supported by Mid-career Researcher Program through NRF grant funded by the Ministry of Education, Science and Technology, Korea (no. 2010–0015186).


  • DWS microrheology
  • Drop-on-demand inkjet
  • Elasticity
  • Infinite shear viscosity
  • Jeffery-Hamel flow
  • Shear thinning
  • Strain hardening

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics


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