Personal InfoBSc 2003, Department of Chemical Engineering, Technion IIT
MSc 2006, Department of Chemical Engineering, Technion IIT
PhD 2010, Department of Mathematics and Statistics, The University of Melbourne
Ofer and his group study the transport, stability, and adsorption of colloidal systems in liquid films. Specifically, the study concentrates on the deposition of colloidal particles for improving fabrication procedures for microelectronic devices, water recovery in the oil industry, and particles/interface dynamics on microfluidic platforms in the presence and absence of acoustic waves.
In his postdoctoral studies, Ofer and colleagues worked on acoustic flows. The study took place at RMIT and at Monash University and was supervised by Prof. Leslie Yeo and Prof. James Friend. The work captured a new phenomenon, known nowadays as ‘Acoustowetting’, in which propagating acoustic waves in a solid body support the spreading of liquid films over the surface of the solid. Acoustowetting is further studied nowadays for coating surfaces in the absence of moving parts, pumping liquid through nano-channels, and for liquid atomization.
Ofer’s PhD research involved the theoretical analysis and simulation of model systems and experimental evidence in the field of colloid physics. The study that took place at The University of Melbourne was supervised by Prof. Derek Chan and Prof. Steven Carnie. Ofer studied the contributions of colloidal forces and micro flows to collisions between solid surfaces, micro-drops, and micro-bubbles, benefiting mining and pharmaceutical industries. In addition, Ofer studied Marangoni flows and surface viscosity effects during his MSc thesis in the Technion. The study that took place at the Technion was supervised by Prof. Avi Nir, and Dr. Olga Lavrenteva.
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The pattern deposition of polymers and nanoparticles from a volatile carrier liquid is employed nowadays for the manufacturing of arrays of electrical circuits, touch screens, infrared antennas, Faraday cages, etc. We use both theory and experiment to study fundamental aspects of pattern deposition. In particular, we concentrate on contributions of colloidal forces (van der Waals forces, electrical double layer forces, molecular steric forces, etc.) between nano-particles and between the particles and the solid substrate to the morphology of the deposit. Another aspect we study is the contribution of the Marangoni flow to pattern deposition. Marangoni flow is excited by variations in the surface tension of a liquid. We concentrate on cases where the surface tension of the suspension is altered due to a phase change of the solute or particles in the liquid during the deposition process.
Stability of colloidal suspensions and emulsions
The stability of suspensions and emulsions determine the shelf life of products that are made of complex fluids, such as milk, paint, shampoo, etc. and the quality of coating and many device fabrication processes. Moreover, the stability of suspensions and emulsions determine the efficiency of separation processes in the mining, petroleum, and chemical industries.
We study the recovery of water that were used in the petroleum industry for the extraction of oil from wells in the ground. The used water product is contaminated by bitumen particles and hydrocarbons in the form of solute molecules and suspended drops. An efficient separation of the contaminates from the water phase is conducted by the destabilisation of the contaminant particles and drops. The destabilised contaminants undergo particle coagulation and drop coalescence, which allow for the extraction of the water phase.
We investigate the destabilisation of the contaminant phases by altering the colloidal forces between the particles and the drops while accounting for hydrodynamic contributions. Theoretical analysis is combined with different model experimental systems for the identification and verification of the mechanisms taking place during the dynamic collision of particles and drops in water and the consequent coagulation and coalescence processes.
Acoustic flow in thin liquid films
The flow of fluid which is excited by acoustic waves is known as acoustic streaming. KHz to MHz acoustic excitations (in particular surface acoustic waves – SAWs – and Flexural waves) are employed nowadays in order to actuate and manipulate liquids and particles on microfluidic lab-on-a-chip platforms, enhance mass and heat transport in fluids, repel water off solid surfaces, etc.
We explore the mechanisms that give rise to the greater efficiency of the process of electro–polishing under the influence of KHz–MHz flexural acoustic waves. In addition, we explore liquid drainage and coating under the influence of MHz surface acoustic waves.
Zigelman and O. Manor. A theoretical analysis of the deposition of colloidal particles from a volatile liquid meniscus in a rectangular chamber. Colloids and Surfaces A: Physicochemical and Engineering Aspects, (DOI: 10.1016/j.colsurfa.2018.02.038) 2018 https://doi.org/10.1016/j.colsurfa.2018.02.038
M. Morozov and O. Manor. Vibration-driven mass transfer and dynamic wetting. Current Opinion in Colloid & Interface Science,
(DOI: 10.1016/j.cocis.2017.12.002) 2018
S. Collignon, O. Manor, J. Friend. Improving and Predicting Fluid Atomization via Hysteresis-Free Thickness Vibration of Lithium Niobate, Adv. Func. Mater. (DOI: 10.1002/adfm.201704359) 2017
A. Zigelman and O. Manor. The deposition of colloidal particles from a sessile drop of a volatile suspension subject to particle adsorption and coagulation, J. Colloids Interface Sci. 509 (195) 2018
H. Horesh, M. Morozov and O. Manor. Enhanced drainage and thinning of liquid films between bubbles and solids which support surface waves, Phys. Rev. E. 95 (05283) 2017 https://doi.org/10.1103/PhysRevE.95.052803
M. Morozov and O. Manor. An extended Landau–Levich model for the dragging of a thin liquid films with a propagating surface acoustic wave, J. Fluid Mech., 810 (307) 2017
S. Mhatre, A. Zigelman, L. Abezgauz, and O. Manor. Influence of a Propagating Megahertz Surface Acoustic Wave on the Pattern Deposition of Solute Mass off an Evaporating Solution, Langmuir (DOI: 10.1021/acs.langmuir.6b01341) 2016 http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.6b01341
G. Altshuler and O. Manor. Free films of a partially wetting liquid under the influence of a propagating MHz surface acoustic wave, Phys. Fluids, 28, (072102) 2016 http://dx.doi.org/10.1063/1.4955414
A. Zigelman and O. Manor. A model for pattern deposition off an evaporating solution subject to contact angle hysteresis and finite solubility, Soft Matter, (DOI: 10.1039/C6SM00579A) 2016
G. Altshuler and O. Manor. Spreading dynamics of a partially wetting water film atop a MHz substrate vibration, Phys. Fluids, 27 (102103) 2015 http://scitation.aip.org/content/aip/journal/pof2/27/10/10.1063/1.4932086
O. Manor. and L. Pismen. Effect of high-frequency in-plane substrate vibration on a three-phase contact angle, Phys. Fluids, 27 (062101) 2015 http://scitation.aip.org/content/aip/journal/pof2/27/6/10.1063/1.4922054
O. Manor, A. R. Rezk, J. R. Friend and L. Y. Yeo. On the dynamics of liquid films exposed to high frequency surface vibration, Phys. Rev. E 91 (053015) 2015 http://journals.aps.org/pre/abstract/10.1103/PhysRevE.91.053015
O. Manor. Diminution of contact angle hysteresis under the influence of an oscil- lating force, Soft Matter, 30(6841) 2014 http://pubs.acs.org/doi/abs/10.1021/la5006924
A. R. Rezk, O. Manor, J. R. Friend and L. Y. Yeo. Double flow reversal in thin liquid films driven by MHz order surface vibration, Proc. Roy. Soc. A, 470(20130765) 2014
O. Manor, J. R. Friend and L. Y. Yeo. Vibration-Induced Wetting, Ency. Surface Colloid Sci., (DOI: 10.1081/E-ESCS-120047379) 2013
D.J. Collins, A. Winkler, O. Manor, L. Y. Yeo, H. Schmidt and J. R. Friend. Droplet size control using surface acoustic wave atomization, Phys. Rev. E, 86(056312) 2012
A. R. Rezk, O. Manor, J. R. Friend and L. Y. Yeo. Anomalous film spreading, fingering instabilities and soliton-like wave trains, Nat. Commun., 3(1167) 2012
O. Manor, L. Y. Yeo, and J. R. Friend. The appearance of boundary layers and drift flows due to high-frequency surface waves, J. Fluid Mech., 707(482) 2012 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8690256
O. Manor, T. T. Chau, G. W. Stevens, D. Y. C. Chan, F. Grieser and R. R. Dagastine. Polymeric stabilised emulsions: steric effects and deformation in soft systems. Langmuir, 28(4599) 2012 http://pubs.acs.org/doi/abs/10.1021/la204272u
O. Manor, M. Dentry, L. Y. Yeo, and J. R. Friend. Substrate dependent drop de- formation and wetting under high frequency vibration. Langmuir, 7(7976) 2011 http://pubs.rsc.org/en/Content/ArticleLanding/2011/SM/c1sm06054f#!divAbstract
O. Manor and D. Y. C. Chan. Influence of surfactants on the force between two bubbles. Langmuir 26(655), 2010 http://pubs.acs.org/doi/abs/10.1021/la902243q
O. Manor and D. Y. C. Chan. Terminal Velocity and Mobile Surface Species in Rising Micro-Bubbles. Langmuir 25(8899) 2009
S. A. Edwards, S. L. Carnie, O. Manor and D. Y. C. Chan. Effects of Internal Flow and Viscosity Ratio on Measurements of Dynamic Forces between Deformable Drops. Langmuir 25(3352), 2009 http://pubs.acs.org/doi/abs/10.1021/la8042473
O. Manor, I. U. Vakarelski, G. W. Stevens, F. Grieser, R. R. Dagastine and D. Y. C. Chan. Dynamic forces between bubbles and surfaces and hydrodynamic boundary conditions. Langmuir 24(11533), 2008
O. Manor, I. U. Vakarelski, X. Tang, S. J. O’Shea, G. W. Stevens, F. Grieser, R. R. Dagastine and D. Y. C. Chan. Hydrodynamic boundary conditions and dynamic forces between bubbles and surfaces. Phys. Rev. Lett. 101(024501), 2008 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.101.024501
D. Y. C. Chan, O. Manor, J. N. Connor and R. G. Horn. From shapes to forces on the nanoscale. Soft Matter 4(471), 2008 http://pubs.rsc.org/en/Content/ArticleLanding/2008/SM/B712924F#!divAbstract
O. Manor, O. Lavrenteva and A. Nir. Effects of non-homogeneous surface viscosity on the Marangoni migration of a droplet in viscous fluid. J. Colloid Interface Sci. 321(142), 2008