INVESTIGATION OF INTERFACIAL INSTABILITIES WITH A TWO- LAYER SLIDE-COATING PROCESS

Transcription

1 INVESTIGATION OF INTERFACIAL INSTABILITIES WITH A TWO- LAYER SLIDE-COATING PROCESS Cornelia K. Buerkin 1, 2, 3, Ike de Vries 1, Sebastian M. Raupp 2, Philip Scharfer 2, Wilhelm Schabel 2, Pim Groen 1 1 Holst Centre, Eindhoven (Netherlands) 2 Institute of Thermal Process Engineering, Thin Film Technology, Karlsruhe Institute of Technology (Germany) 3 Corresponding author: cornelia.buerkin@web.de Presented at the 18th International Coating Science and Technology Symposium, September 19-21, 2016, Pittsburgh, PA (United States) Supporting information Used latin and greek symbols: g Gravitational acceleration in m/s² h Film height in µm u Velocity in x-direction in m/s y Cartesian coordinates β Angle of inclination in η Viscosity coefficient in mpas ρ Density in g/cm³ τ Shear stress in mpa Calculation of velocity profiles The velocity profile of the two flow is derived from the Navier-Stokes equations characterized with the boundary conditions of no slip for the liquid-plate interface and zero shear for the liquid-air interface, neglecting air resistance (eq. 3) 41; 42. No-slip condition at plate Zero shear condition at surface u 1 (y=0) = 0 eq. 3 The liquid-liquid interface has the boundary conditions of velocity continuity and equal stress (eq. 4)

2 Velocity continuity at interface Equal stress at interface eq. 4 u 1 (y= h 1 ) = u 2 (y= h 1 ) Results in: The velocity profiles for the bottom and top liquids are given in equations 6 and 7, using the abbreviations A 1 and A 2 of equation 5. Abbreviations: eq. 5 Bottom velocity: Top velocity: eq. 6 eq

3 Fluid properties Table 3: List of used solvents and their properties based on literature values. Solvent CAS Molecular Density Viscosity Surface Weight [g/mol] [g/cm 3 ] at t=20 C [mpas] at t=20 C Tension [mn/m] at t=20 C Water Toluene p-xylene Isopropanol Cyclopentanone at Propane-1,2-diol C 26 Anisole Poly Glycol Monomethyl Ether Acetate (PGMEA) at 25 C 34 Ethylene Glycol

4 Table 4: Selected slide coater combinations indicated with their interfacial tension measured with EasyDrop. If the droplet was too large or the contrast adjustable, the value was evaluable 25. Cyclopentanone Bottom liquid Isopropanol Top liquid Anisole Ethylene glycol Cyclopentanone Propane- 1,2-diol Anisole PGMEA Xylene 2.21±0.04 mn/m Water evaluable Xylene evaluable 10.40±0.05 mn/m 4.16±0.04 mn/m evaluable References 25. Buerkin, C., "Investigation of interfacial stabilities in a multi slide-coating process." Master Thesis. Karlsruhe, Eindhoven : Karlsruhe Institute of Technology (2016) 26. Riddick, J. A., Bunger, W. B. and Sakano, T. K., "Organic Solvents. Physical Properties and Methods of Purification." 2 4th Edition. New York : John Wiley & Sons (1986) 34. Kyowa Hakko Chemical Co., Ltd. Texas A&M University. Materials Characterization Facility. [Online] [Cited: June 2, 2016.] DDBST GmbH. Dynamic Viscosity of 2-Propanol. [Online] [Zitat vom: 2. June 2016.] Dr. Ahmad, Munir. Imperial College London. Department of Electrical and Electronic Engineering. [Online] [Cited: June 2, 2016.]

5 38. Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung. GESTIS- Stoffdatenbank. [Online] [Cited: June 02, 2016.] ChemicalDictionary.org. [Online] [Cited: June 2, 2016.] Chen, K., "Wave formation in the gravity-driven low-reynolds number flow of two liquid films down an inclined plane." Physics of Fluids A, 5 (12) (1993) 41. Spurk, J. H. ad Aksel, N. "Strömungslehre : Einführung in die Theorie der Strömungen." 7th Edition, Berlin, Heidelberg : Springer-Verlag (2007) 42. Kao, T. W. "Stability of Two Layer Viscous Stratified Flow Down an Inclined Plane." Physics of Fluids, 8 (5) (1965) 43. Morrison, Dr. Faith A. Common Boundary Conditions in Fluid Mechanics.Handouts CM3110 Transport Processes I. Michigan Technological University. [Online] [Cited: June 23, 2016.]