
NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
Recipient: |
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Initial Amendment Date: | August 26, 2016 |
Latest Amendment Date: | August 30, 2018 |
Award Number: | 1605809 |
Award Instrument: | Standard Grant |
Program Manager: |
Karl Rockne
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
Start Date: | September 1, 2016 |
End Date: | December 31, 2020 (Estimated) |
Total Intended Award Amount: | $328,441.00 |
Total Awarded Amount to Date: | $362,789.00 |
Funds Obligated to Date: |
FY 2018 = $34,348.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
W5510 FRANKS MELVILLE MEMORIAL LIBRARY STONY BROOK NY US 11794-0001 (631)632-9949 |
Sponsor Congressional District: |
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Primary Place of Performance: |
NY US 11794-2300 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): |
SSA-Special Studies & Analysis, EnvE-Environmental Engineering |
Primary Program Source: |
01001819DB NSF RESEARCH & RELATED ACTIVIT |
Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
1605809
Colosqui, Carlos
This project will examine an innovative approach for separation of water and oils, generally defined as organic compounds insoluble in water, by tuning the in wetting/de-wetting dynamics of drainage and absorption dynamics in engineered porous media. This project will advance the fundamental knowledge of (dynamic) wetting and liquid adhesion on "real" surfaces having complex nano- and microscale structure. The new knowledge will advance technologies for anti-fouling, drag reduction, and micro/nano-fluidic handling, having large impacts on the U.S. economy, infrastructure, and the environment.
Recent theoretical developments by the PI indicate that the dynamics of the wetting process, present nontrivial regimes not described by conventional continuum-based and deterministic predictions. These theoretical predictions have been confirmed by molecular dynamics simulations and, more recently, through experimental work by the PI's group and other groups. Building upon these developments this project will examine the feasibility of exploiting novel phenomena such as the crossover from capillary-driven to thermally-activated wetting for innovative technical applications. The accomplishment of specific research objectives will be enabled by interdisciplinary and complementary skills of the PI and Co-PIs. To understand this will require incorporating the effects of thermal motion of the contact line which dominate the dynamics as mechanical equilibrium is approached. This project aims to generate fundamental knowledge required to understand and control the dynamics of spontaneous and forced imbibition or drainage in nano/microstructured media such as synthetic filters, sponges, and fabrics, or soil, sandstone, and biological membranes. The research hypothesis this project will examine is that significant asymmetries in wetting/de-wetting dynamics (wetting hysteresis) of different liquid pairs on micro/nanostructured surfaces can be designed and controlled to engineered capillary "diodes" for efficient separation of immiscible liquids. The PIs approach to test this hypothesis is to use the surface nano/microstructure to control dynamic hysteresis effects that will lead to fast or slow (arrested) wetting depending on the direction of motion of the wetting line and physicochemical properties of the liquids (e.g., viscosity, density, interfacial tensions). The central objective of this project is to generate fundamental knowledge required to understand and control the dynamics of spontaneous and forced imbibition/drainage by different liquid pairs on nano/micro-structured media such as synthetic filters, sponges, and fabrics, or soil, sandstone, and biological membranes. Building upon theoretical developments and preliminary experimental results the project has two specific objectives: (1) Tuning the crossover points between fast and slow wetting regimes; (2) Controlling the relaxation rate in the slow (kinetic) regime. Theoretical predictions will guide the selection of experimental parameters and physical conditions to accomplish two specific objectives: (1) Tuning the crossover point between fast and slow wetting regimes; and, (2) Controlling the relaxation rate in the slow (kinetic) regime. The proposed research has the potential to be highly transformative to environmental remediation and water treatment. The engagement of students and underrepresented minorities is extensive from graduate education to K-12.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Outline.
Combining experimental studies, micro/nanofabrication, and theoretical analysis this project has examined the feasibility of an innovative approach based on capillary action for the separation of water and oils, generally defined as organic compounds insoluble in water. We have designed, fabricated, and tested simple fluidic devices called capillary diodes (Figure 1) for potential application in passive separation and filtering processes for immiscible liquids in water. The concept is analogous to conventional diodes, since a junction between two surfaces with dissimilar surface energies induce a threshold pressure head that must be overcome to observe the ?forward? transport of certain liquid pairs. In vertical imbibtion, the threshold pressure head corresponds to a critical immersion depth of the device inlet (Figure 1).
Intellectual merit
By designing the surface micro/nanostructure and geometry of the capillary conducts with section having dissimilar surface energies we proved that one can effectively promote or prevent the spontaneous (capillarity driven) imbibition of selected fluid pairs (e.g., water-air, oil-air, water-oil). Our work has been able to predict, induce, and control the effective hydrodynamic conductivity and the threshold pressure head to observe imbibition (forward liquid displacement) and drainage (backward liquid displacement) of water and oils in a rectangular glass capillary that was partially micro/nanotextured using a single-step laser-based fabrication method. The fabrication approach developed and employed as a part of this project produces both a well-defined micropattern with controlled geometry and the deposition of nanomaterial with complex morphologies (Figure 2). The nanomaterial deposition and coverage extent was a critical factor to control the surface energy and resulting affinity of different liquids to each section the device surface.
The key hypothesis that this project examined and verified is that significant asymmetries in the wetting and de-wetting dynamics by specific fluid pairs (water-air, oil-air, oil-water) can be effectively controlled through the surface micro/nanostructured in order to engineered capillary "diodes" for potential applications as passive separators and filters for immiscible organic liquids in water. To test or working hypothesis, we employed a laser-based method to design and fabricate surfaces having microscale patterns and complex nanoscale structures that once infused by water or oil break the symmetry of the energies and forces required for wetting/de-wetting and the associated forward/backward fluid transport inside the device. This resulted in the ability to prevent the spontaneous imbibition and wetting by simple oils when the micro/nanopatterned slits were pre-infused by water and immersed in water-oil mixtures at controlled immersion depths that were predicted by analytical models (Figure 3).
Broader impacts
The research work in this project has contributed to the fundamental knowledge of (dynamic) wetting/dewetting processes and liquid adhesion phenomena on surfaces having complex micro/ nanostructure. A better understanding of these phenomena is relevant to a wide range of natural processes and industrial applications. The new knowledge gained and the predictive models produced in this project can help develop new strategies for anti-fouling, drag reduction, and micro/nano-fluidic handling in diverse engineering applications. The theoretical developments and experimental analysis produced by this project indicate that the dynamics of imbibition and drainage processes present nontrivial regimes with long-lived metastable states that are not described by conventional continuum-based predictions (e.g., the Lucas-Washburn equation). To understand the presence of metastable states and the hindering of imbibition or drainage by different liquid pairs required new analytical descriptions considering the effects of thermal motion and the surface nanostructure, which largely dominate the wetting dynamics near thermodynamic equilibrium conditions. This project has thus generated fundamental knowledge and analytical tools to help understand and control the dynamics of imbibition and drainage in synthetic nano/microstructured materials such as filters, sponges, and fabrics, or natural porous media that are relevant to environmental engineering applications such as soil, sandstone, or biological membranes.
This project supported 3 PhD students who have graduated during the completion of the project, 2 of these students belong to underrepresented minorities in STEM.
Last Modified: 06/09/2021
Modified by: Carlos E Colosqui
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