Liquid film entrainment during dip coating on a saturated porous substrate

Sathyanath, Rahul; Aarthi, A.; Kalpathy, Sreeram K.

doi:10.1016/j.ces.2020.115552

Cited by 21 publications

(4 citation statements)

References 36 publications

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“…The film thickness in the dip coating can be explained using the Landau-Levich model, which relies on the gravityinduced viscous drag of the Newtonian fluid. [24,25] The thickness of the film is based on the surface tension and viscosity of the fluid, which is proportional to the withdrawal speed. Based on this, the morphological and cross-sectional structures were analyzed.…”

Section: Preparation Of Bf Balloonsmentioning

confidence: 99%

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

Lee,

Park,

Kim

et al. 2023

Adv Materials Technologies

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Recently, bioabsorbable vascular stents (BVSs) are actively studied owing to their ability to dissolve within the human body. However, despite their advantages, BVSs often dislodge from the expandable balloon‐based delivery system when transported to the lesion site. In this study, a novel methodology aiming at increasing the retention force between the stent and the delivery system is presented. The breath‐figure method is adopted to form a porous structure and enhance adhesion. Additionally, numerical and experimental methods are used to evaluate the effect of surface tension between two immiscible fluids (polymeric solutions and droplets). To control the interfacial tension between the solution and droplets, an amphiphilic polymer and NaCl‐added vapor are used. By selecting the appropriate parameters, a sponge‐like structure is prepared on the stent delivery system. To verify its applicability, the two types of structures presented in this study are experimentally compared. These findings provide valuable guidelines for understanding the mechanism of breath‐figure patterns. Thus, the innovative methodology developed in this study demonstrates simplicity and scalability for large‐area production, making it potentially applicable to industrial technologies and offering new insights into biomedical engineering.

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Section: Preparation Of Bf Balloonsmentioning

confidence: 99%

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

Lee,

Park,

Kim

et al. 2023

Adv Materials Technologies

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“…The process is still a hot spot for research. The recent areas of study include coating a substrate with a suspension of spherical particles [40], the effect of substrate surface porosity on the entrainment process [42], the characteristics of the liquid sheet ejected by a rotating disc substrate under conditions of high inertia [29], the drag-out of non-Newtonian fluids [43,46] and deriving formulae to predict the flux of coating liquid on non-flat, e.g. circular, substrate [47].…”

Section: Introductionmentioning

confidence: 99%

Parametric study of the oleophilic skimming process: CFD simulation using VOF model

Lotfy

2023

J Mar Sci Technol

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Oleophilic skimming is a primary alternative when addressing oil spill accidents. However, the existing literature does not define accurately the optimum design and operating conditions of the oleophilic skimmer. In this research, an extensive CFD investigation was conducted on the performance of the drum skimmer. Seven parameters were tested, namely drum diameter, drum centre height, oil slick thickness, rotational speed, oil density, oil viscosity and oil surface tension. The simulations were performed by applying the volume of fluid technique using the OpenFOAM package. The two-dimensional numerical setup was tested for grid size, domain extension and time-step convergence, and the results were validated with experimental data from the literature. The skimmer performance was evaluated through the oil recovery rate and water ingestion rate. The study illustrated that the oleophilic drum skimmer best functions at rotational speed within 30–60 rpm, drum diameter within 200–300 mm, drum centre-height-to-diameter ratio within 0.3–0.4, oil slick thickness $$\ge$$ ≥ 15 mm and oil viscosity within 10–100 cSt.

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“…Dip coating of Newtonian viscous fluids on different substrates has been studied in various applications and significant progress in the understanding of the fluid mechanics of film formation has been achieved [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Among different substrates, fibers and rods are the most challenging to coat: the curvature of the cylinder significantly influences the film deposition kinetics by altering the flow pattern in the meniscus region [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

The Thickness and Structure of Dip-Coated Polymer Films in the Liquid and Solid States

2022

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Films formed by dip coating brass wires with dilute and semi-dilute solutions of polyvinyl butyral in benzyl alcohol were studied in their liquid and solid states. While dilute and semi-dilute solutions behaved as Maxwell viscoelastic fluids, the thickness of the liquid films followed the Landau-Levich-Derjaguin prediction for Newtonian fluids. At a very slow rate of coating, the film thickness was difficult to evaluate. Therefore, the dynamic contact angle was studied in detail. We discovered that polymer additives preserve the advancing contact angle at its static value while the receding contact angle follows the Cox–Voinov theory. In contrast, the thickness of solid films does not correlate with the Landau-Levich-Derjaguin predictions. Only solutions of high-molecular-weight polymers form smooth solid films. Solutions of low-molecular-weight polymers may form either solid films with an inhomogeneous roughness or solid polymer domains separated by the dry substrate. In technological applications, very dilute polymer solutions of high-molecular-weight polymers can be used to avoid inhomogeneities in solid films. These solutions form smooth solid films, and the film thickness can be controlled by the experimental coating conditions.

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Liquid film entrainment during dip coating on a saturated porous substrate

Cited by 21 publications

References 36 publications

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

Parametric study of the oleophilic skimming process: CFD simulation using VOF model

The Thickness and Structure of Dip-Coated Polymer Films in the Liquid and Solid States

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