Effects of shear and extensional rheology on liquid transfer between two flat surfaces

Wu, Jyun Ting; Carvalho, Márcio S.; Kumar, Satish

doi:10.1016/j.jnnfm.2019.104173

Cited by 15 publications

(22 citation statements)

References 54 publications

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“…PEO solutions are commonly used to investigate viscoelastic behavior of liquid jets, 28,29 beads-ona-string, 10,14,30,31 coatings [32][33][34] and liquid transfer. 25,27 Broadly, our strategy is to control the shear viscosity with PEG and the extensional viscosity with the mass fraction of PEO. The molecular weight of PEO is 8 × 10 6 g/mol and the molecular weight of PEG is 20 000 g/mol, according to Sigma-Aldrich.…”

Section: Sample Preparationmentioning

confidence: 99%

“…The effect of viscoelastic polymer solutions on T r for the gravure printing is studied experimentally by Sankaran and Rothstein, 25 and numerically by Lee et al 26 In the beginning, the liquid transfer is governed by the early stretching dynamics, while the final amount of liquid transfer occurs through the delayed viscoelastic filament thinning. [25][26][27] In contrast, the present study focuses on the cylindrical shaped liquid bridges, with the pinned contact lines on disks to overcome the shearing effect. 27 In the present paper, our experimental study mainly focuses on T r for a cylindrical-shaped bridge of viscoelastic, as well as Newtonian fluids.…”

Section: Introductionmentioning

confidence: 99%

“…[25][26][27] In contrast, the present study focuses on the cylindrical shaped liquid bridges, with the pinned contact lines on disks to overcome the shearing effect. 27 In the present paper, our experimental study mainly focuses on T r for a cylindrical-shaped bridge of viscoelastic, as well as Newtonian fluids. Solutions will be prepared by varying mass fraction and molecular weight of polymers to investigate the effect of viscoelasticity on liquid transfer.…”

Section: Introductionmentioning

confidence: 99%

“…The same stainless steel disks at the top and bottom will be used to overcome the complexities due to different surface materials as previously reported. 15,16,27 Different disk diameters, initial and final aspect ratios, along with the initial profile curvatures are explored.…”

Section: Introductionmentioning

confidence: 99%

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Liquid Transfer for Viscoelastic Solutions

Pingulkar,

Peixinho,

Crumeyrolle

2021

Preprint

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Viscoelastic liquid transfer from one surface to another is a process that finds applications in many technologies, primarily in printing. Here, cylindrical shaped capillary bridges pinned between two parallel disks are considered. Specifically, the effects of polymer mass fraction, solution viscosity, disk diameter, initial aspect ratio, final aspect ratio, stretching velocity and filling fraction (alike contact angle) are experimentally investigated in uniaxial extensional flow. Both Newtonian and viscoelastic polymer solutions are prepared using polyethylene glycol (PEG) and polyethylene oxide (PEO), with a wide variety of mass fractions. The results show that the increase in polymer mass fraction and solvent viscosity reduces the liquid transfer to the top surface. Moreover, the increase in the initial and final stretching height of the capillary bridge also decreases the liquid transfer, for both Newtonian and viscoelastic solutions. Finally, the shape of the capillary bridge is varied by changing the liquid volume. Now, Newtonian and viscoelastic solutions exhibit opposite behaviors for the liquid transfer. These findings are discussed in terms of interfacial shape instability and gravitational drainage.

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Section: Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Liquid Transfer for Viscoelastic Solutions

Pingulkar,

Peixinho,

Crumeyrolle

2021

Preprint

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“…[27] In this case, the mismatch of different medium still represents a limit for the functionality of the manipulation systems, and to overcome this issue, horizontal liquid bridges have been extensively studied from a theoretical point of view, [28] whereas vertical liquid bridges have been very recently explored for transferring liquid volumes in air between two vertically separating flat surfaces. [29,30] In the manipulation context of liquid and micro-objects, an important role has been recently played by the pyroelectric effect (PYT), already exploited for high-resolution inkjet printing and manipulation of polymers. [31][32][33] Herein, we propose, for the first time, a tweezing system based on the PYT for miniaturized actuation, accurate remote locomotion, and lift against the force of gravity of liquids volumes and micro-objects by thermal stimulus.…”

Section: Introductionmentioning

confidence: 99%

Pyroelectric Tweezers for Handling Liquid Unit Volumes

Nasti

Coppola

Vespini

et al. 2020

Advanced Intelligent Systems

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Liquids are the primary environments in which chemical, physical, and biological processes occur. Considering a liquid bridge as liquid unit volume (LUV) element, it is highly desirable to develop reliable tools for handling such volumes. Herein, a sort of intelligent microfluidic platform based on the pyroelectric‐electrohydrodynamics (EHD) is shown for manipulating liquid bridges and thus performing multiple functions in a flexible and simple way. Several basic operations with liquid bridges using an EHD‐pin matrix based on the pyroelectric effect engineered in ferroelectric crystals are demonstrated. By activating pyro‐EHD effect in predetermined positions (pins of the array), the locomotion and handling of single or multiple LUVs simultaneously are controlled. In particular, multiple operations such as lift, displacement, mixing, stretching, and carrying vector for microparticles, are shown. These tweezers based on a pyro‐EHD matrix can open the route for a multipurpose platform driven by physical intelligence and can be used for driving locomotion and operate manifolds functionalities in many areas of science and technology at microscale as well as nanoscale with advantages to be activated by the sole thermal stimulus, controlled remotely, and in noncontact mode.

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