Numerical Simulation of a High Temperature Polymer Electrolyte Membrane Fabrication Process

Bhamidipati, Kanthi Latha; Harris, Tequila A. L.

doi:10.1115/1.4001321

Cited by 12 publications

(9 citation statements)

References 41 publications

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“…This decrease in the critical web velocities for the onset of a coating defect with increasing viscosity suggests that the fluid viscosity has a negative impact on the size of the operating window. This behavior is consistent with the literature observations for the case of homogenous Newtonian solutions …”

Section: Resultssupporting

confidence: 93%

“…Previous studies on dilute particle dispersions have reported that, when the coating defect is air entrainment, the addition of particles to a coating fluid improves the coating window . However, in the case of fumed silica nanoparticle dispersions in PPG the coating defect is ribbing, where the ribbing instability is known to occur due to large adverse pressure gradient, a different mechanism compared to air entrainment, which is commonly associated with a failure of dynamic wetting contact line . Lin et al have examined the influence of particle addition when the coating defect was ribbing.…”

Section: Resultsmentioning

confidence: 99%

“…The Weissenberg number is defined as the product of the fluid relaxation time, λ , and shear rate imposed,

\dot{γ}

. A few studies also exist investigating the effect of shear‐thinning on slot‐die coating through a combination of experiments, using homogenous blackstrap molasses, and computations . An increased shear‐thinning behavior was found to maximize the delay on the onset of air entrainment …”

Section: Introductionmentioning

confidence: 99%

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The effect of shear‐thickening on the stability of slot‐die coating

Khandavalli

Rothstein

2016

AIChE Journal

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Slot‐die coating is an economical roll‐to‐roll processing technique with potential to revolutionize the fabrication of nano‐patterned thin films at high throughput. In this study, the impact of shear‐thickening of the coating fluid on the stability of slot‐die coating was investigated. For the coating fluid, a model system fumed silica nanoparticles dispersed in polypropylene glycol was chosen. These dispersions exhibit shear and extensional thickening characterized through steady shear and capillary break‐up measurements. The critical web velocity for the onset of coating defect for different flow rates was measured, while the type of coating defect was visualized using a high speed camera. For the shear thickening particle dispersions, the coating failed through the onset of a ribbing instability. The critical web velocity for the onset of coating defect was found to decrease with increasing particle concentration and increasing fluid viscosity. The minimum wet thickness was studied as a function of capillary number for the particle dispersions and compared with a series of Newtonian fluids with similar viscosities. In all cases, shear‐thickening behavior was found to stabilize coating by reducing the minimum wet coating thickness when compared against a Newtonian fluid with similar viscosity at the same capillary number. Conversely, the shear‐thinning fluids tested destabilized the coating by increasing the minimum wet thickness when compared against a Newtonian at the same capillary number. The impact of shear‐thickening on slot‐die coating was further studied by quantifying the evolution of the ribbing instability with increasing web speed and by conducting tests over a wide range of coating gaps. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4536–4547, 2016

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

“…The Weissenberg number is defined as the product of the fluid relaxation time, λ , and shear rate imposed,

\dot{γ}

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of shear‐thickening on the stability of slot‐die coating

Khandavalli

Rothstein

2016

AIChE Journal

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“…[ 67 ] In addition, some coating defects such as ribbing, dripping, rivulets, and air entrainment will occur during the coating process. [ 70,71 ] Despite this, slot‐die coating is still a versatile process which is widely used for fabricating thin and uniform films, such as in polymer electrolyte membrane fuel cells, [ 72,73 ] solar cells, [ 74,75 ] lithium‐ion batteries, [ 76,77 ] and flexible organic electronics. [ 78,79 ] In recent years, slot‐die coating is also successfully applied in fabricating large‐area perovskite films, the following text will summarize the recent advances in highly efficient PSCs using slot‐die coating method.…”

Section: The Advances Of Various Large‐scale Fabrication Methodsmentioning

confidence: 99%

Insights into Large‐Scale Fabrication Methods in Perovskite Photovoltaics

Niu

Chen

et al. 2020

Adv Energy and Sustain Res

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As an emerging sunlight‐harvesting material, halide perovskite has obtained extensive achievements on device efficiency and stability in the past decade. Especially, the efficiency of lab‐scale perovskite solar cells (PSCs, 25.2%) is already comparable with that of crystalline silicon solar cells. However, the development of large‐scale perovskite solar modules is far behind small area devices due to difficult fabrication process and stringent requirements for film quality, the Achilles’ heel to hinder their commercialization. Therefore, the coating techniques of perovskite modules need to be developed and optimized continuously. Moreover, the underlying mechanism along with these coating processes should be revealed urgently. Herein, the recent advances for several popular coating methods are systematically summarized that are widely applied in the deposition of large‐scale films. The relevant mechanistic study, including the formation of wet film, and subsequent nucleation and growth kinetics during coating process, are discussed. The main target is to gain insight into the large‐scale PSCs fabrication. Hopefully, useful guidance is provided to further improvement of efficiency and stability of PSCs, which finally promotes their commercialization.

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“…Existing studies on the issue of modeling penetration are almost related with these three coating methods. Among these three coating methods, slot die coating has attracted increased attention in recent years for manufacturing of membrane fuel cells, solar cells, lithium‐ion batteries, and flexible organic electronics . This is because slot die coating is a premetered process by which the thickness of the coated layer can be controlled precisely.…”

Section: Modeling Domainmentioning

confidence: 99%

Review on penetration and transport phenomena in porous media during slot die coating

Ding

Harris

2017

J Polym Sci B Polym Phys

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A distinctive field in the coatings industry is coating of porous media, which has broad applications including paper, textiles, electronics, filtration, and energy sectors. Fluid penetration is an important issue during direct coating of a liquid bead on porous media, which is driven by the pressure from an external flow field and the surface tension in the porous media. Generally, during the coating process, some level of penetration is desirable to obtain specific material properties, but inadequate or excessive penetration is detrimental. To help control the level of penetration, understanding relationships between operating parameters and penetration are highly desirable. In this article, the current state of academic research on modeling penetration in porous media during common coating processes, especially the slot die coating process, is reviewed. Specifically, the challenges, basic ideas, advantages, and disadvantages of macroscale, microscale, and pore-network models on penetration in porous media are discussed. This article concludes with some recommendations for future work.

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Numerical Simulation of a High Temperature Polymer Electrolyte Membrane Fabrication Process

Cited by 12 publications

References 41 publications

The effect of shear‐thickening on the stability of slot‐die coating

The effect of shear‐thickening on the stability of slot‐die coating

Insights into Large‐Scale Fabrication Methods in Perovskite Photovoltaics

Review on penetration and transport phenomena in porous media during slot die coating

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