scholarly journals Infrared microlenses and gratings of chalcogenide: confined self-organization in solution processed thin liquid films

RSC Advances ◽  
2018 ◽  
Vol 8 (49) ◽  
pp. 27946-27955 ◽  
Author(s):  
Priyanka Sachan ◽  
Radhakant Singh ◽  
Prabhat K. Dwivedi ◽  
Ashutosh Sharma
Keyword(s):  
Thin Films ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Self Organization ◽  
Glassy Material ◽  
Solution Processed ◽  
Micro Structures ◽  
Liquid Thin Films

Directed self-organization of a glassy material is demonstrated to generate ultra smooth, optically useful micro structures such as lens arrays and gratings. Liquid thin films of chalcogenide re-organize within the confinement provided by the mould.

scholarly journals Double flow reversal in thin liquid films driven by megahertz-order surface vibration

2014 ◽  
Vol 470 (2169) ◽  
pp. 20130765 ◽  
Author(s):  
Amgad R. Rezk ◽  
Ofer Manor ◽  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Thin Films ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Intermolecular Forces ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Propagation Direction ◽  
Flow Reversal ◽  
Order Surface ◽  
Over Time

Arising from an interplay between capillary, acoustic and intermolecular forces, surface acoustic waves (SAWs) are observed to drive a unique and curious double flow reversal in the spreading of thin films. With a thickness at or less than the submicrometre viscous penetration depth, the film is seen to advance along the SAW propagation direction, and self-similarly over time t 1/4 in the inertial limit. At intermediate film thicknesses, beyond one-fourth the sound wavelength λ ℓ in the liquid, the spreading direction reverses, and the film propagates against the direction of the SAW propagation. The film reverses yet again, once its depth is further increased beyond one SAW wavelength. An unstable thickness region, between λ ℓ /8 and λ ℓ /4, exists from which regions of the film either rapidly grow in thickness to exceed λ ℓ /4 and move against the SAW propagation, consistent with the intermediate thickness films, whereas other regions decrease in thickness below λ ℓ /8 to conserve mass and move along the SAW propagation direction, consistent with the thin submicrometre films.

Spin-coating of vertically stratified thin liquid films

2010 ◽  
Vol 647 ◽  
pp. 265-285 ◽  
Author(s):  
A. McINTYRE ◽  
L. N. BRUSH
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Lower Layer ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Uniform Thickness ◽  
Viscous Forces ◽  
Liquid Free Surface ◽  
Device Applications ◽  
Lower Liquid

Spin-coating is a process used to fabricate thin films for device applications. In this paper, lubrication theory is used to derive an axisymmetric model for the spin-coating of two immiscible vertically stratified Newtonian thin films. The model includes gravitational, van der Waals, capillary and viscous forces, differences in liquid layer properties and evaporation/condensation effects. Thinning calculations focus on the effects of viscosity and condensation/evaporation. In this case, for layers of uniform thickness, the lower layer thins monotonically yet never reaches zero thickness. With evaporation mass loss the upper layer disappears in finite time, whereas with condensation effects the upper layer approaches a steady-state thickness. Fully nonlinear calculations are carried out for films with non-uniform thickness and the deviation of the interfaces from the flat state is monitored. In general, disturbances to the lower layer have a greater effect on the upper layer than those of disturbances of the upper layer on the lower layer. Disturbances along the upper gas–liquid free surface propagate outward more rapidly than those along the lower liquid–liquid interface and disturbances that decrease the film thickness tend to dissipate more slowly.

Transport Properties of Polyelectrolyte Solutions. Effect of Confinement in Thin Liquid Films

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Jérôme Delacotte ◽  
Dominique Langevin
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Conductivity Measurements ◽  
Polyelectrolyte Solutions

AbstractThe role of condensed counterions in transport properties, such as electrical conductivity and viscosity, has been investigated with solutions of a flexible polyelectrolyte. Comparisons with existing theories are proposed. Viscosity is strongly affected by confinement in thin films, depending whether polyelectrolyte chains are adsorbed or not at the film surfaces. The role of counterion mobility is however difficult to assess because the measurements are not accurate enough. It is proposed that this role could be tested by electrical conductivity measurements.

scholarly journals Dynamics of thin liquid films on vertical cylindrical fibres

2019 ◽  
Vol 865 ◽  
pp. 303-327 ◽  
Author(s):  
H. Ji ◽  
C. Falcon ◽  
A. Sadeghpour ◽  
Z. Zeng ◽  
Y. S. Ju ◽  
...  
Keyword(s):  
Thin Films ◽  
Stability Analysis ◽  
Wave Solution ◽  
Liquid Films ◽  
Travelling Wave ◽  
Thin Liquid Films ◽  
Travelling Wave Solution ◽  
Slip Boundary Conditions ◽  
Slip Boundary ◽  
Physical Effects

Recent experiments on thin films flowing down a vertical fibre with varying nozzle diameters present a wealth of new dynamics that illustrate the need for more advanced theory. We present a detailed analysis using a full lubrication model that includes slip boundary conditions, nonlinear curvature terms and a film stabilization term. This study brings to focus the presence of a stable liquid layer playing an important role in the full dynamics. We propose a combination of these physical effects to explain the observed velocity and stability of travelling droplets in the experiments and their transition to isolated droplets. This is also supported by stability analysis of the travelling wave solution of the model.

HEAT TRANSFER IN THIN LIQUID FILMS FLOWING DOWN HEATED INCLINED GROOVED PLATES

2010 ◽  
Vol 2 (5) ◽  
pp. 455-468 ◽  
Author(s):  
Hongyi Yu ◽  
Karsten Loffler ◽  
Tatiana Gambaryan-Roisman ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Liquid Films ◽  
Thin Liquid Films

Sulfur-Vacancy Passivation in Solution-Processed Sb2S3 Thin Films: Influence on Photovoltaic Interfaces

2019 ◽  
Vol 3 (1) ◽  
pp. 810-821 ◽  
Author(s):  
Abhishek Maiti ◽  
Soumyo Chatterjee ◽  
Amlan J. Pal
Keyword(s):  
Thin Films ◽  
Sulfur Vacancy ◽  
Solution Processed
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