Liquid Transfer for Viscoelastic Solutions

Abstract

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 and polyethylene oxide, 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 heights 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.

Two-Dimensional Piezoelectric Nanofibrous Webs by Self-Polarized Assembly for High-Performance PM0.3 Filtration

“…The viscosity ratio (λ) represents the ratio of the viscosity of the polymer solution to the viscosity of the solvent, which usually depends on the polymer concentration. 39 As Oh → ∞ and λ → ∞, the droplets were retractive and stable on the substrates. By decreasing λ, the triple contact line (TCL) moved but was pinched by the viscosity force.…”

“…In contrast, a small Oh represents an inertia flow where the droplet spreading was dominated by the inertial and interfacial force with the absence of viscosity force. The viscosity ratio (λ) represents the ratio of the viscosity of the polymer solution to the viscosity of the solvent, which usually depends on the polymer concentration . As Oh → ∞ and λ → ∞, the droplets were retractive and stable on the substrates.…”

The Influence of the Gravure Printing Quality on the Layer Functionality: The Study Case of LFP Cathode for Li-Ion Batteries

“…Namely, using Ca approach unity as a method for both the ink formulation and printing process, the functional assessment of the gravure printed cathodes is discussed. Although it may seem like a relatively simple process, gravure printing has a complex multi-physical nature, involving capillarity, viscoelasticity, inertia, gravity, moving contact lines, and solvent evaporation changing ink composition, which makes modeling extremely challenging [6,16,17]. Since many different physical quantities are involved, dimensional analysis is typically used to simplify the complex gravure printing process, representing a useful tool for describing the physical system's behavior.…”

Gravure Printing for PVDF Thin-Film Pyroelectric Device Manufacture

“…The gravure printing process can be seen as a sequence of sub-processes (inking, doctoring, transfer, spreading, drying), each with its ideal operating regime controlling the final material arrangement in the printed layer [78]. Due to the complex multi-physical nature of this process, involving capillarity, viscoelasticity, inertia, gravity, moving contact lines and solvent evaporation changing ink composition, dimensional analysis can represent a useful tool for studying the physical system behavior [71,82,83]. At the microscopic level, the fluid dynamics of the gravure printing process are governed by the balance between viscous and surface tension forces, where the latter are the driving forces [71,84].…”