scholarly journals Evaporation Effect on Thickness Distribution for Spin-Coated Films on Rectangular and Circular Substrates

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1322
Author(s):  
Ying Yan ◽  
Jiarun Li ◽  
Qiuyu Liu ◽  
Ping Zhou
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Spin Coating ◽  
Film Formation ◽  
Thickness Distribution ◽  
Dominant Factor ◽  
Two Phase ◽  
Thin Film Fabrication ◽  
Significant Difference ◽  
Coated Film

Spin-coating is widely applied in the field of thin-film fabrication due to its simplicity and high film uniformity. To prepare thin films on rectangular substrates by spin-coating, the simulation and experimental methods were used to study the characteristics of the film thickness in this work. The two-phase flow simulations of spin-coating on a rectangular substrate and circular substrate were carried out with the volume of fluid (VOF) method. The simulation results showed that the airflow field and the substrate geometry had little effect on the evolution of spin-coated film thickness. However, in the experimental results, there was a significant difference in the thickness of the spin-coated film on the rectangular substrate and the circular substrate. According to further study, the solvent evaporation that was neglected in the simulation was the dominant factor of the differences. In addition, it was concluded that the non-uniform evaporation caused by the surface tension and edge accumulation in the later spin-coating stage was the main reason for the film accumulation of the windward area on the rectangular substrate. This work is useful to obtain a deeper understanding of the thin-film formation mechanism of spin-coating.

Computationally Efficient Modelling of Oil Jet-Breakup and Film Formation for Bearing Chamber Applications

2018 ◽  
Author(s):  
Jee Loong Hee ◽  
Kathy Simmons ◽  
Bruce Kakimpa ◽  
David Hann
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Film Formation ◽  
Viscous Sublayer ◽  
Current Data ◽  
Turbulent Dispersion ◽  
Research Centre ◽  
Shear Stresses ◽  
Two Phase ◽  
Injection Point

In previously published experimental work completed at the Gas Turbine and Transmissions Research Centre (G2TRC), oil fed to an aeroengine location bearing via underrace feed was seen to shed from the cage, forming a film on static surfaces near the bearing and subsequently shedding into the bearing chamber. A high-fidelity computational model of the two-phase flow in an aeroengine bearing chamber must adequately reproduce such behaviour but there are significant challenges in modelling both the oil breakup after shedding and the subsequent film formation. It is very computationally costly to resolve an oil film interface using the Volume of Fluid (VOF) approach at regions of thin film and it is unacceptably inaccurate to resolve thick film using an explicit thin film modelling technique such as the Eulerian Thin Film Model (ETFM). A proposed solution is to couple together VOF, ETFM and discrete phase modelling (DPM). Previously published G2TRC work shows how VOF and ETFM can be successfully coupled. This paper investigates the coupling of ETFM and DPM. The evaluation of film momentum transport and air-particle momentum transfer/Lagrangian particle tracking are studied using a low Reynolds number turbulence model. Validation is required to ensure that these models work together as intended. To this end a preliminary CFD study was carried out on a published case investigated experimentally and computationally in which a jet is injected into a duct via a nozzle, breaking up into droplets before forming a wall film. The droplets are produced by primary atomization due to liquid instabilities at the injection point. Secondary breakup occurs due to surface instabilities prompted by the high-velocity cross-flow. Small droplets are transported downstream whereas larger droplets deflect minimally hitting the wall and forming a thin film. In the work presented here quantitative film thickness data from experiments and prior simulations are compared to current data. The success of the simulation is found to depend on shear-transportation, turbulent dispersion of the particles, particle grouping, mass transportation as well as accurate prediction of interfacial shear-stresses. With suitable modelling parameters it was possible to predict film thickness to within 28.9% of those seen experimentally. The present ETFM-DPM modelling showed improvements over previously published models in prediction of shear-stresses and film transportation as the ω-equation could be integrated through the viscous sublayer. The developed approach is now mature enough to be applied to the bearing chamber geometry investigated experimentally at G2TRC and this is proposed for future work.

A Novel Ethanol-Based Non-Particulate Ink for Spin-Coating Cu2ZnSnS4 Thin Film

2021 ◽  
Vol 16 (2) ◽  
pp. 136-141
Author(s):  
Jingyuan Zhang ◽  
Yusheng Liu ◽  
Jianing Song ◽  
Mu Zhang ◽  
Xiaodong Li
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Spin Coating ◽  
Treatment Temperature ◽  
Coated Film ◽  
Coating Method ◽  
Pre Treatment ◽  
Cu2znsns4 Thin Film ◽  
Czts Thin Films

The Cu2ZnSnS4 (CZTS) thin films were fabricated by the direct solution coating method using a novel non-particulate ink. The ink was formulated using ethanol as the solvent and 1,2-diaminopropane as the complex-ing agent. The pure phase kesterite films with good crystallinity, large-sized crystals and excellent electrical properties were prepared by the spin-coating deposition technique using the homogeneous and air-stable ink. It was found that the subsequent pre-treatment temperature had an influence on the film crystallinity and electrical properties. The best film was obtained by pre-treating the spin-coated film at 250 °C, and then post-annealing at 560 °C. The film shows a narrow bandgap of 1.52 eV and excellent electrical properties, with a resistivity of 0.07 Ocm, carrier concentration of 3.0 x 1017 cm-3, and mobility of 4.15 cm2 V-1 s-1. The novel non-particulate ink is promising for printing high quality CZTS thin films as absorber layers of thin film solar cells.

Simulation of the organic thin film thickness distribution for multi-source thermal evaporation process

Vacuum ◽  
2010 ◽  
Vol 85 (3) ◽  
pp. 448-451 ◽  
Author(s):  
Hu Chen ◽  
Yang Gang ◽  
Chen Wenbin ◽  
Luo Kaijun ◽  
Liu Feng
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Thermal Evaporation ◽  
Thickness Distribution ◽  
Evaporation Process ◽  
Organic Thin Film ◽  
Thin Film Thickness

Optical Interferometric Observations of the Effects of a Bump on Point Contact EHL

1992 ◽  
Vol 114 (4) ◽  
pp. 779-784 ◽  
Author(s):  
M. Kaneta ◽  
T. Sakai ◽  
H. Nishikawa
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Numerical Simulations ◽  
Contact Region ◽  
Thickness Distribution ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Interesting Phenomenon ◽  
Contact Conditions ◽  
Average Speed

The effects of surface kinematic conditions on micro-elastohydrodynamic lubrication (micro-EHL) are investigated under rolling and/or sliding point contact conditions using the optical interferometry technique. A long bump of chromium sputtered on the surface of a highly polished ball is used as a model asperity. It is shown that the film thickness distribution or the elastic deformation of the bump is influenced significantly by the surface kinematic conditions and the orientation of the bump. An interesting phenomenon is also found when contacting surfaces move with different speeds; the thin film formed on a transversely oriented bump existing at the entrance of the contact travels through the contact region at the average speed of the surfaces. The experimental results obtained qualitatively confirm published numerical simulations.

Controlling thin film thickness distribution in two dimensions

2001 ◽  
Author(s):  
David M. Broadway ◽  
Michael D. Kriese ◽  
Yuriy Y. Platonov
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Thickness Distribution ◽  
Two Dimensions ◽  
Thin Film Thickness

Prediction of film inversion in two-phase flow in coiled tubes

1992 ◽  
Vol 236 ◽  
pp. 497-511 ◽  
Author(s):  
G. F. Hewitt ◽  
S. Jayanti
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Two Phase Flow ◽  
Thickness Distribution ◽  
Thin Liquid Film ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
New Criterion ◽  
Good Agreement

Depending on the flow conditions, the liquid film in annular two-phase flow in coiled tubes may be pushed towards the outer or the inner side by the centrifugal force. It is important to understand the mechanism of this ‘film inversion’ in order to develop a predictive model for the film thickness distribution. In this paper, this phenomenon is studied analytically, and a new criterion, based on the secondary flow in the thin liquid film, is proposed to predict its occurrence. The criterion shows good agreement with available experimental data. It is suggested that the analytical model can readily be extended to predict the distribution of the film thickness and film flow rate in coiled tubes.

Thin film thickness distribution by alpha absorption

1960 ◽  
Vol 7 (2) ◽  
pp. 160-166 ◽  
Author(s):  
M. De Croës ◽  
W. Parker ◽  
K. Sevier
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Thickness Distribution ◽  
Thin Film Thickness
Sign in / Sign up

Export Citation Format

Share Document