Coating flow of non-Newtonian fluids on a flat rotating disk

Jenekhe, Samson A.; Schuldt, S. B.

doi:10.1021/i100016a009

Cited by 99 publications

(35 citation statements)

References 3 publications

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“…To account for evaporation, Meyerhofer 2 included a correction based on the assumption that the spin-coating process consists of two different stages: (a) a ow dominated phase followed by (b) an evaporation dominated phase. There are reports 19,20 that further characterize the uid ow of non-Newtonian liquids. Later on, Cregan and O'Brien 21 considered that the solvent evaporation is simultaneous with the ow dominated phase because the solvent starts to evaporate once the suspension is pipetted on to the spinning substrate.…”

Section: Previous Resultsmentioning

confidence: 99%

Magnetorheology from surface coverage of spin-coated colloidal films

Pichumani

González-Viñas

2013

Soft Matter

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In magnetorheological fluids, the viscosity usually increases with the field and the non-Newtonian character of these complex fluids may vary significantly. We provide a new method to measure the relative viscosity of a superparamagnetic colloid, by applying a magnetic field during a spin-coating process, which involves evaporation of the solvent. We define the compact equivalent height to take into account the discrete nature of the suspension, and we compare experimental results under different conditions. We extend the model of Cregan et al. (J. Colloid Interface Sci., 2007, 314, 324) to turn it into an evaporation rate independent one. The generality of the resulting model facilitates measurement of the magnetic field dependent viscosity. We also discuss the morphologies of the final dried colloidal deposits and the possible mechanisms involved in their formation.

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Section: Previous Resultsmentioning

confidence: 99%

Magnetorheology from surface coverage of spin-coated colloidal films

Pichumani

González-Viñas

2013

Soft Matter

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“…Numerous groups have addressed this using different viscosity laws. [15][16][17][18] The behavior of film thinning of nonNewtonian fluids has now been modelled numerically. 19 However, the effect of evaporation and the consequences of height-dependent viscosity on thinning rate were not considered.…”

Section: B Thinning Of Polymer Solutionsmentioning

confidence: 99%

Dynamics of polymer film formation during spin coating

Mouhamad

Mokarian‐Tabari

Clarke

et al. 2014

Journal of Applied Physics

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Standard models explaining the spin coating of polymer solutions generally fail to describe the early stages of film formation, when hydrodynamic forces control the solution behavior. Using in situ light scattering alongside theoretical and semi-empirical models, it is shown that inertial forces (which initially cause a vertical gradient in the radial solvent velocity within the film) play a significant role in the rate of thinning of the solution. The development of thickness as a function of time of a solute-free liquid (toluene) and a blend of polystyrene and poly(methyl methacrylate) cast from toluene were fitted to different models as a function of toluene partial pressure. In the case of the formation of the polymer blend film, a concentration-dependent (Huggins) viscosity formula was used to account for changes in viscosity during spin coating. A semi-empirical model is introduced, which permits calculation of the solvent evaporation rate and the temporal evolution of the solute volume fraction and solution viscosity.

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“…This pioneering work has been widely employed in the subsequent investigations on spin coating. For example, Acrivos et al [2], Jenekhe and Schuldt [3] extended the analysis of Emslie [1] to study the flow of a power-law liquid on a rotating disk. Whereas Charpin et al [4] investigated the axisymmetric spin coating of power law and Ellis fluids.…”

Section: Introductionmentioning

confidence: 99%

Thermocapillary flow of thin Cu-water nanoliquid film during spin coating process

Maity¹

2017

Int Nano Lett

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Unsteady flow of thin Cu-water nanoliquid film over a horizontal rotating disk is studied numerically using finite difference technique under the assumption of planar interface. It is also assumed that the disk is cooling axisymmetrically from below. The effects of the nanolayer thickness and nanoparticle radius are considered for investigation. It is found that the film thinning rate decreases with increase of the nanoparticle volume fraction. It is also found that thickness of liquid decreases with increase of the thermocapillary parameter. The results show that the rate of film thinning is more for the thermal conductivity model of Yu and Choi [47] compared to the model of Maxwell [46]. It is observed that the film thinning rate increases with increase of nanolayer thickness but it decreases with the nanoparticle radius. A curve R ¼ R c ðz; tÞ in R À z plane is delineated along which temperature gradient T z is zero and positive or negative according to R\R c or R [ R c respectively. Furthermore, it is shown that the region for T z [ 0 enlarges with increase of the nanoparticle volume fraction and the nanolayer thickness.

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Coating flow of non-Newtonian fluids on a flat rotating disk

Cited by 99 publications

References 3 publications

Magnetorheology from surface coverage of spin-coated colloidal films

Magnetorheology from surface coverage of spin-coated colloidal films

Dynamics of polymer film formation during spin coating

Thermocapillary flow of thin Cu-water nanoliquid film during spin coating process

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