Final Report Summary - SBL (Study of high frequency vibration induced steady wetting and of high frequency vibration induced nanoparticle assembly for molecular electronics)
One of the main goals of nowadays-scientific research is to develop methods to prompt and control natural processes?at nanometer and micrometer resolutions for advancing technological capabilities at such length resolutions. Many corresponding examples exist, from which we highlight the field of molecular electronics as an example. Although advanced remarkably in recent years, this field lacks cheap and efficient integration methods for fabricating nano- and micro-scale complex and inter- and intra-connected artificial structures made of large quantities of electronic building-blocks such as gold nano-particles, carbon nano-tubes, polymeric semiconductor wires, and other molecules of electronic viability.
Further, in recent years one has observed an increasing interest in the patterned deposition of solute molecules or colloidal particles from an evaporating carrier liquid. Traditionally this interest has been in avoiding the formation of unwanted patterns of solute material in coating processes. Nowadays, however, patterned deposition is employed by various companies to replace classical clean-room and photolithography processes with this method in order to generate medium resolution, one layer, and simple geometry electric circuitry on large surfaces. Further applications presented in recent academic studies include separation processes, the manufacturing of optical resonators, and the fabrication of photo-functional surfaces.
In this project we study the physics associated with translating MHz and higher frequency electronic signals to MHz surface acoustic waves (SAWs) that invoke uniquely determined micron and submicron non-linear flow patterns, capable of integrating particulate suspensions into structures
To date we have been using microfluidic platforms in the laboratory and theoretical insights in order to demonstrate the SAW may invoke dynamic wetting of liquids atop solids; the principles of which support the interference of the SAW with the convective pattern deposition of a non-volatile solute mass from an evaporating solvent, also known as the coffee-ring effect.
MHz SAWs in a solid substrate support the convective wetting or de-wetting of liquid films. We showed that the dynamic wetting transition is dependent on a balance between the Stokes drift of mass the SAW invokes in the liquid film and capillary stress. We observed motion of the three phase contact line should the stress associated with the drift of liquid mass overcame the capillary stress. We then further introduced an evaporating liquid that contained solute and colloidal particles. We showed the mechanisms that alter the dynamic wetting properties of the liquid interfere with the pattern deposition of the non volatile solute or particle phase on the solid substrate.
Our model systems were shown to de-wet the solid substrate parallel to the propagating front of the SAW. The hundred-nanometer viscous penetration depth of the SAW into the solution appeared to support a Stokes drift of mass in the de-wetting meniscus of the solution, opposing the evaporative convection of the solute. The drift appears to reduce the variations in the concentration of the solute near the de-wetting meniscus and thus to reduce the deriving mechanism for a patterned deposition, occurring in the absence of the SAW. The deposited patterns under SAW appear then to take the topography of a solid film rather than of the separated patterns to appear in the absence of the SAW.
Our goal is to deposit several layers of SAW controlled layers of solute or colloidal mass, one on top of the other. This study will then contribute to establishing procedures for 3D printing of nano to micro scale designs, where the solution or suspension is the ?ink? and the natural pattern formation due to the evaporating carrier liquid and the SAW excitation are the passive and active carriers of information about the pattern to be printed, respectively. This procedure is thus meant to replace the highly polluting, expensive, and slow photolithography production of electrical circuitry with the cheap, fast, and low pollution method we develop.
The PI transitioned almost five years ago from Melbourne, Australia, where he worked in RMIT University to its current position in the Technion at Haifa, Israel. The CIG program has helped the PI to commence his research program by funding the preliminary stage in which the PI has being establishing the foundations of his laboratory and his research program. Further, during this period the PI has been supervising 4 MSc and 3 PhD graduate students. The PI has further established connections with the European community in the fields of Soft Matter, and Colloid and Interface Science and with Israeli academics in the Ben Gurion University, Ariel University, and Tel-Aviv University that work in similar fields of research. In addition, the PI has been teaching several undergraduate courses, namely, Process analysis using Numerical Methods, Particulate liquids, Student Research course, and Principles of Chemical Engineering 2 (heat and mass transfer).
Further, in recent years one has observed an increasing interest in the patterned deposition of solute molecules or colloidal particles from an evaporating carrier liquid. Traditionally this interest has been in avoiding the formation of unwanted patterns of solute material in coating processes. Nowadays, however, patterned deposition is employed by various companies to replace classical clean-room and photolithography processes with this method in order to generate medium resolution, one layer, and simple geometry electric circuitry on large surfaces. Further applications presented in recent academic studies include separation processes, the manufacturing of optical resonators, and the fabrication of photo-functional surfaces.
In this project we study the physics associated with translating MHz and higher frequency electronic signals to MHz surface acoustic waves (SAWs) that invoke uniquely determined micron and submicron non-linear flow patterns, capable of integrating particulate suspensions into structures
To date we have been using microfluidic platforms in the laboratory and theoretical insights in order to demonstrate the SAW may invoke dynamic wetting of liquids atop solids; the principles of which support the interference of the SAW with the convective pattern deposition of a non-volatile solute mass from an evaporating solvent, also known as the coffee-ring effect.
MHz SAWs in a solid substrate support the convective wetting or de-wetting of liquid films. We showed that the dynamic wetting transition is dependent on a balance between the Stokes drift of mass the SAW invokes in the liquid film and capillary stress. We observed motion of the three phase contact line should the stress associated with the drift of liquid mass overcame the capillary stress. We then further introduced an evaporating liquid that contained solute and colloidal particles. We showed the mechanisms that alter the dynamic wetting properties of the liquid interfere with the pattern deposition of the non volatile solute or particle phase on the solid substrate.
Our model systems were shown to de-wet the solid substrate parallel to the propagating front of the SAW. The hundred-nanometer viscous penetration depth of the SAW into the solution appeared to support a Stokes drift of mass in the de-wetting meniscus of the solution, opposing the evaporative convection of the solute. The drift appears to reduce the variations in the concentration of the solute near the de-wetting meniscus and thus to reduce the deriving mechanism for a patterned deposition, occurring in the absence of the SAW. The deposited patterns under SAW appear then to take the topography of a solid film rather than of the separated patterns to appear in the absence of the SAW.
Our goal is to deposit several layers of SAW controlled layers of solute or colloidal mass, one on top of the other. This study will then contribute to establishing procedures for 3D printing of nano to micro scale designs, where the solution or suspension is the ?ink? and the natural pattern formation due to the evaporating carrier liquid and the SAW excitation are the passive and active carriers of information about the pattern to be printed, respectively. This procedure is thus meant to replace the highly polluting, expensive, and slow photolithography production of electrical circuitry with the cheap, fast, and low pollution method we develop.
The PI transitioned almost five years ago from Melbourne, Australia, where he worked in RMIT University to its current position in the Technion at Haifa, Israel. The CIG program has helped the PI to commence his research program by funding the preliminary stage in which the PI has being establishing the foundations of his laboratory and his research program. Further, during this period the PI has been supervising 4 MSc and 3 PhD graduate students. The PI has further established connections with the European community in the fields of Soft Matter, and Colloid and Interface Science and with Israeli academics in the Ben Gurion University, Ariel University, and Tel-Aviv University that work in similar fields of research. In addition, the PI has been teaching several undergraduate courses, namely, Process analysis using Numerical Methods, Particulate liquids, Student Research course, and Principles of Chemical Engineering 2 (heat and mass transfer).