TY - JOUR
T1 - The retraction of jetted slender viscoelastic liquid filaments
AU - Sen, Uddalok
AU - Datt, Charu
AU - Segers, Tim
AU - Wijshoff, Herman
AU - Snoeijer, Jacco H.
AU - Versluis, Michel
AU - Lohse, Detlef
N1 - Funding Information:
The support from an Industrial Partnership Programme of the Netherlands Organisation for Scientific Research (NWO), cofinanced by Canon Production Printing B.V., University of Twente, and Eindhoven University of Technology is acknowledged. C.D. and J.H.S. acknowledge support from NWO VICI Grant No. 680-47-632.
Publisher Copyright:
©
PY - 2021/12/25
Y1 - 2021/12/25
N2 - Long and slender liquid filaments are produced during inkjet printing, which can subsequently either retract to form a single droplet, or break up to form a primary droplet and one or more satellite droplets. These satellite droplets are undesirable since they degrade the quality and reproducibility of the print, and lead to contamination within the enclosure of the print device. Existing strategies for the suppression of satellite droplet formation include, among others, adding viscoelasticity to the ink. In the present work, we aim to improve the understanding of the role of viscoelasticity in suppressing satellite droplets in inkjet printing. We demonstrate that very dilute viscoelastic aqueous solutions (concentrations∼0.003%concentrations∼0.003% wt. polyethylene oxide, corresponding to nozzle Deborah number Den∼3Den∼3) can suppress satellite droplet formation. Furthermore, we show that, for a given driving condition, upper and lower bounds of polymer concentration exist, within which satellite droplets are suppressed. Satellite droplets are formed at concentrations below the lower bound, while jetting ceases for concentrations above the upper bound (for fixed driving conditions). Moreover, we observe that, with concentrations in between the two bounds, the filaments retract at velocities larger than the corresponding Taylor–Culick velocity for the Newtonian case. We show that this enhanced retraction velocity can be attributed to the elastic tension due to polymer stretching, which builds up during the initial jetting phase. These results shed some light on the complex interplay between inertia, capillarity and viscoelasticity for retracting liquid filaments, which is important for the stability and quality of inkjet printing of polymer solutions.
AB - Long and slender liquid filaments are produced during inkjet printing, which can subsequently either retract to form a single droplet, or break up to form a primary droplet and one or more satellite droplets. These satellite droplets are undesirable since they degrade the quality and reproducibility of the print, and lead to contamination within the enclosure of the print device. Existing strategies for the suppression of satellite droplet formation include, among others, adding viscoelasticity to the ink. In the present work, we aim to improve the understanding of the role of viscoelasticity in suppressing satellite droplets in inkjet printing. We demonstrate that very dilute viscoelastic aqueous solutions (concentrations∼0.003%concentrations∼0.003% wt. polyethylene oxide, corresponding to nozzle Deborah number Den∼3Den∼3) can suppress satellite droplet formation. Furthermore, we show that, for a given driving condition, upper and lower bounds of polymer concentration exist, within which satellite droplets are suppressed. Satellite droplets are formed at concentrations below the lower bound, while jetting ceases for concentrations above the upper bound (for fixed driving conditions). Moreover, we observe that, with concentrations in between the two bounds, the filaments retract at velocities larger than the corresponding Taylor–Culick velocity for the Newtonian case. We show that this enhanced retraction velocity can be attributed to the elastic tension due to polymer stretching, which builds up during the initial jetting phase. These results shed some light on the complex interplay between inertia, capillarity and viscoelasticity for retracting liquid filaments, which is important for the stability and quality of inkjet printing of polymer solutions.
KW - UT-Hybrid-D
UR - https://doi.org/10.1017/jfm.2021.855
U2 - 10.1017/jfm.2021.855
DO - 10.1017/jfm.2021.855
M3 - Article
SN - 0022-1120
VL - 929
JO - Journal of fluid mechanics
JF - Journal of fluid mechanics
M1 - A25
ER -