Effect of liquid elasticity on the behaviour of high-speed focused jets

Abstract

We investigate the effect of highly contrasting non-Newtonian liquid properties on the formation of liquid jets with a focused shape. By using two nozzle-free ejection techniques, mechanically impact- and laser-induced, fast jets of a highly elastic (sodium polyacrylate) and weakly elastic (xanthan-gum) diluted polymer solutions are generated. A unique high-speed effect is encountered at the jet ejection onset of the highly elastic solution. Its jet-tip speed is on average 1.4 times faster in comparison to a Newtonian (glycerin/water) and the weakly elastic liquids. We explain this effect occurring as a result of the high viscoelasticity of the sodium polyacrylate solution. Additionally, a ‘bungee jumper’ jet behaviour (Morrison and Harlen in Rheol Acta 49(6):619–632, 2010) is observed in a regime of high speed ($$10<V_j<40$$ 10 < V j < 40 m/s) and high viscosity ($$\mu >20$$ μ > 20 mPa s) not previously examined. We additionally characterise the viscoelastic non-breakup jet limit using the Bazilevskii et al. (Fluid Dyn 40(3):376–392, 2005) ejection criterion. Herein, the extensional rheological parameters are measured implementing a novel DoS-CaBER technique (Dinic et al. in Lab Chip 17(3):460–473, 2017). Our findings may influence results of inkjet printing technologies and recent nozzle-free ejection systems for ejecting liquids with non-Newtonian properties. Graphical abstract

A phase diagram of the pinch-off-type behavior of impulsively-induced viscoelastic liquid jets

“…6(a). This phenomenon was also observed in a previous study as a 'bungee-jumper jet' when the elasticity of the solution is large (Franco-Gómez et al, 2021), and it is believed that the elastic force contributes to the pulling back of the jet. We define such a jet that pulls back to the initial interface after maximum elongation as a 'no-pinch-off jet'.…”

“…However, these studies have been limited to the injection of low-velocity (< O(10 0 ) m/s) and low-viscosity (< 20 mPa•s) solutions used in conventional inkjet printing (Franco-Gómez et al, 2021). In recent years, next-generation printing technologies such as 3D printing (Truby and Lewis, 2016) and artificial cell printing (Noor et al, 2019) have been developed.…”

Solvent Properties Influence the Rheology and Pinching Dynamics of Polyelectrolyte Solutions: Thickening the Pot with Glycerol and Cellulose Gum

“…Additional details about the experimental setup and design considerations, specific advantages of DoS rheometry contrasted to other extensional rheology methods, and the various approaches to analyzing radius evolution datasets are included in our previous contributions. ,,,− ,− We investigate and describe the extensional rheological response of complex fluids such as neutral and charged polymer solutions, inks, nail lacquers, surfactant-based cosmetics (shampoos and conditioners), proteins such as egg albumin, spinnable polymer solutions, , and foods (honey, molasses, mayo, and ketchup). ,,,− ,− Since we introduced DoS rheometry in 2015, it has emerged as the method of choice for innumerable studies benefitting from the virtues of a simplified, cost-efficient setup and the ability to analyze the pinching dynamics and extensional rheological response of complex fluids, including those with viscosity comparable to water or weak elasticity, even with sub-millisecond relaxation times. − …”

Evaporation and Rheology Chart the Processability Map for Centrifugal Force Spinning

“…The DoS videos are analyzed with ImageJ and specially written MATLAB codes to determine the minimum neck radius as a function of time. The DoS rheometry setup, design considerations, specific advantages contrasted to other extensional rheology methods, and various approaches to analyzing datasets are detailed in our previous contributions, − ,,,− and in several recent studies. − We used a closed transparent cell to carry out experiments in an atmosphere saturated with solvent vapor. Even though we find that evaporation exercises negligible influence for unentangled aqueous solutions, a closed cell is needed for volatile-entangled (VE) polymer solutions that display strong concentration-dependent change in rheology.…”