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Álvarez-Cuartas JD, González-Cabrera DL, Camargo M. Epitaxial growth in one dimension. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:463001. [PMID: 39111342 DOI: 10.1088/1361-648x/ad6c98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 08/07/2024] [Indexed: 08/24/2024]
Abstract
The final structure and properties of layers grown by epitaxy techniques are determined in the very early stage of the process. This review describes one-dimensional models for epitaxial growth, emphasizing the basic theoretical concepts employed to analyze nucleation and aggregation phenomena in the submonolayer regime. The main findings regarding the evolution of quantities that define the properties of the system, such as monomer and island densities, and the associated island size, gap length, and capture zone distributions are discussed, as well as the analytical tools used to evaluate them. This review provides a concise overview of the most widely used algorithms for simulating growth processes, discusses relevant experimental results, and establishes connections with existing theoretical studies.
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Affiliation(s)
| | | | - Manuel Camargo
- DCA & CICBA, Universidad Antonio Nariño-Campus Farallones, Km 18 vía Cali-Jamundí, 760030 Cali, Colombia
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2
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Akdeniz B, Wood JA, Lammertink RGH. Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5934-5944. [PMID: 38451220 PMCID: PMC10956496 DOI: 10.1021/acs.langmuir.3c03916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
Diffusiophoresis, the movement of particles under a solute concentration gradient, has practical implications in a number of applications, such as particle sorting, focusing, and sensing. For diffusiophoresis in an electrolyte solution, the particle velocity is described by the electrolyte relative concentration gradient and the diffusiophoretic mobility of the particle. The electrolyte concentration, which typically varies throughout the system in space and time, can also influence the zeta potential of particles in space and time. This variation affects the diffusiophoretic behavior, especially when the zeta potential is highly dependent on the electrolyte concentration. In this work, we show that adsorbing a single bilayer (or 4 bilayers) of a polyelectrolyte pair (PDADMAC/PSS) on the surface of microparticles resulted in effectively constant zeta potential values with respect to salt concentration throughout the experimental range of salt concentrations. This allowed a constant potential model for diffusiophoretic transport to describe the experimental observations, which was not the case for uncoated particles in the same electrolyte system. This work highlights the use of simple polyelectrolyte pairs to tune the zeta potential and maintain constant values for precise control of diffusiophoretic transport.
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Affiliation(s)
- Burak Akdeniz
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Jeffery A. Wood
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Rob G. H. Lammertink
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
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3
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Alessio BM, Gupta A. Diffusiophoresis-enhanced Turing patterns. SCIENCE ADVANCES 2023; 9:eadj2457. [PMID: 37939177 PMCID: PMC10631721 DOI: 10.1126/sciadv.adj2457] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023]
Abstract
Turing patterns are fundamental in biophysics, emerging from short-range activation and long-range inhibition processes. However, their paradigm is based on diffusive transport processes that yield patterns with shallower gradients than those observed in nature. A complete physical description of this discrepancy remains unknown. We propose a solution to this phenomenon by investigating the role of diffusiophoresis, which is the propulsion of colloids by a chemical gradient, in Turing patterns. Diffusiophoresis enables robust patterning of colloidal particles with substantially finer length scales than the accompanying chemical Turing patterns. A scaling analysis and a comparison to recent experiments indicate that chromatophores, ubiquitous in biological pattern formation, are likely diffusiophoretic and the colloidal Péclet number controls the pattern enhancement. This discovery suggests that important features of biological pattern formation can be explained with a universal mechanism that is quantified straightforwardly from the fundamental physics of colloids.
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Affiliation(s)
- Benjamin M. Alessio
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, USA
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4
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Samanta S, Mahapatra P, Ohshima H, Gopmandal PP. Diffusiophoresis of Weakly Charged Fluid Droplets in a General Electrolyte Solution: An Analytical Theory. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12452-12466. [PMID: 37615654 DOI: 10.1021/acs.langmuir.3c01667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Owing to the importance of analytical results for electrokinetics of colloidal entities, we performed a mathematical analysis to determine the closed form analytical results for the diffusiophoretic velocity of a hydrophobic and polarizable fluid droplet. A comprehensive mathematical model is developed for diffusiophoresis, considering the background aqueous medium as general electrolytes (e.g., binary valence-symmetric/asymmetric electrolytes and a mixed solution of binary electrolytes). We performed our analysis under a weak concentration gradient, and the analytical results for diffusiophoretic velocity are calculated within the Debye-Hückel electrostatic framework. The exact form of the diffusiophoretic velocity is further approximated with negligible error, and the approximate form is found to be free from any of the cumbersome exponential integrals and thus very convenient for practical use. The present theory also covers the diffusiophoresis of perfectly dielectric as well as perfectly conducting droplets as its limiting case. In addition, we have further derived a number of closed form expressions for diffusiophoretic velocity pertaining to several particular cases, and we observed that the derived limit correctly recovers the available existing analytical results for diffusiophoretic velocity. Thus, the present analytical theory for diffusiophoresis can be applied to a wide class of fluidic droplets, e.g., hydrophobic and dielectric oil/conducting mercury droplets, air bubbles, nanoemulsions, as well as any polarizable and hydrophobic fluidic droplet suspended in a solution of general electrolytes.
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Affiliation(s)
- Susmita Samanta
- Department of Mathematics, National Institute of Technology Durgapur, Durgapur 713209, India
| | - Paramita Mahapatra
- Department of Mathematics, National Institute of Technology Durgapur, Durgapur 713209, India
| | - H Ohshima
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Partha P Gopmandal
- Department of Mathematics, National Institute of Technology Durgapur, Durgapur 713209, India
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5
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Chakra A, Singh N, Vladisavljević GT, Nadal F, Cottin-Bizonne C, Pirat C, Bolognesi G. Continuous Manipulation and Characterization of Colloidal Beads and Liposomes via Diffusiophoresis in Single- and Double-Junction Microchannels. ACS NANO 2023; 17:14644-14657. [PMID: 37458750 PMCID: PMC10416570 DOI: 10.1021/acsnano.3c02154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 07/10/2023] [Indexed: 08/09/2023]
Abstract
We reveal a physical mechanism that enables the preconcentration, sorting, and characterization of charged polystyrene nanobeads and liposomes dispersed in a continuous flow within a straight micron-sized channel. Initially, a single Ψ-junction microfluidic chip is used to generate a steady-state salt concentration gradient in the direction perpendicular to the flow. As a result, fluorescent nanobeads dispersed in the electrolyte solutions accumulate into symmetric regions of the channel, appearing as two distinct symmetric stripes when the channel is observed from the top via epi-fluorescence microscopy. Depending on the electrolyte flow configuration and, thus, the direction of the salt concentration gradient field, the fluorescent stripes get closer to or apart from each other as the distance from the inlet increases. Our numerical and experimental analysis shows that although nanoparticle diffusiophoresis and hydrodynamic effects are involved in the accumulation process, diffusio-osmosis along the top and bottom channel walls plays a crucial role in the observed particles dynamics. In addition, we developed a proof-of-concept double Ψ-junction microfluidic device that exploits this accumulation mechanism for the size-based separation and size detection of nanobeads as well as for the measurement of zeta potential and charged lipid composition of liposomes under continuous flow settings. This device is also used to investigate the effect of fluid-like or gel-like states of the lipid membranes on the liposome diffusiophoretic response. The proposed strategy for solute-driven manipulation and characterization of colloids has great potential for microfluidic bioanalytical testing applications, including bioparticle preconcentration, sorting, sensing, and analysis.
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Affiliation(s)
- Adnan Chakra
- Department
of Chemical Engineering, Loughborough University, Loughborough, LE11 3TU, United Kingdom
- Department
of Chemistry, University College London, London, WC1H 0AJ, United Kingdom
| | - Naval Singh
- Manchester
Centre for Nonlinear Dynamics, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Goran T. Vladisavljević
- Department
of Chemical Engineering, Loughborough University, Loughborough, LE11 3TU, United Kingdom
| | - François Nadal
- Commissariat
à l’Énergie Atomique, BP2, 33114, Le Barp, France
| | - Cécile Cottin-Bizonne
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon 1- CNRS, Université de Lyon, Villeurbanne Cedex, 69622, France
| | - Christophe Pirat
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon 1- CNRS, Université de Lyon, Villeurbanne Cedex, 69622, France
| | - Guido Bolognesi
- Department
of Chemical Engineering, Loughborough University, Loughborough, LE11 3TU, United Kingdom
- Department
of Chemistry, University College London, London, WC1H 0AJ, United Kingdom
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6
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Raj RR, Shields CW, Gupta A. Two-dimensional diffusiophoretic colloidal banding: optimizing the spatial and temporal design of solute sinks and sources. SOFT MATTER 2023; 19:892-904. [PMID: 36648425 DOI: 10.1039/d2sm01549h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Diffusiophoresis refers to the phenomenon where colloidal particles move in response to solute concentration gradients. Existing studies on diffusiophoresis, both experimental and theoretical, primarily focus on the movement of colloidal particles in response to one-dimensional solute gradients. In this work, we numerically investigate the impact of two-dimensional solute gradients on the distribution of colloidal particles, i.e., colloidal banding, induced via diffusiophoresis. The solute gradients are generated by spatially arranged sources and sinks that emit/absorb a time-dependent solute molar rate. First we study a dipole system, i.e., one source and one sink, and discover that interdipole diffusion and molar rate decay timescales dictate colloidal banding. At timescales shorter than the interdipole diffusion timescale, we observe a rapid enhancement in particle enrichment around the source due to repulsion from the sink. However, at timescales longer than the interdipole diffusion timescale, the source and sink screen each other, leading to a slower enhancement. If the solute molar rate decays at the timescale of interdipole diffusion, an optimal separation distance is obtained such that particle enrichment is maximized. We find that the partition coefficient of solute at the interface between the source and bulk strongly impacts the optimal separation distance. Surprisingly, the diffusivity ratio of solute in the source and bulk has a much weaker impact on the optimal dipole separation distance. We also examine an octupole configuration, i.e., four sinks and four sources, arranged in a circle, and demonstrate that the geometric arrangement that maximizes enrichment depends on the radius of the circle. If the radius of the circle is small, it is preferred to have sources and sinks arranged in an alternating fashion. However, if the radius of the circle is large, a consecutive arrangement of sources and sinks is optimal. Our numerical framework introduces a novel method for spatially and temporally designing the banded structure of colloidal particles in two dimensions using diffusiophoresis and opens up new avenues in a field that has primarily focused on one-dimensional solute gradients.
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Affiliation(s)
- Ritu R Raj
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
| | - C Wyatt Shields
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Ankur Gupta
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
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7
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Singh N, Vladisavljević GT, Nadal F, Cottin-Bizonne C, Pirat C, Bolognesi G. Enhanced Accumulation of Colloidal Particles in Microgrooved Channels via Diffusiophoresis and Steady-State Electrolyte Flows. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14053-14062. [PMID: 36350104 PMCID: PMC9686125 DOI: 10.1021/acs.langmuir.2c01755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The delivery of colloidal particles in dead-end microstructures is very challenging, since these geometries do not allow net flows of particle-laden fluids; meanwhile, diffusive transport is slow and inefficient. Recently, we introduced a novel particle manipulation strategy, based on diffusiophoresis, whereby the salt concentration gradient between parallel electrolyte streams in a microgrooved channel induces the rapid (i.e., within minutes) and reversible accumulation, retention, and removal of colloidal particles in the microgrooves. In this study, we investigated the effects of salt contrast and groove depth on the accumulation process in silicon microgrooves and determined the experimental conditions that lead to a particle concentration peak of more than four times the concentration in the channel bulk. Also, we achieved an average particle concentration in the grooves of more than twice the concentration in the flowing streams and almost 2 orders of magnitude larger than the average concentration in the grooves in the absence of a salt concentration gradient. Analytical sufficient and necessary conditions for particle accumulation are also derived. Finally, we successfully tested the accumulation process in polydimethylsiloxane microgrooved channels, as they are less expensive to fabricate than silicon microgrooved substrates. The controlled and enhanced accumulation of colloidal particles in dead-end structures by solute concentration gradients has potential applications in soft matter and living systems, such as drug delivery, synthetic biology, and on-chip diagnostics.
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Affiliation(s)
- Naval Singh
- Department
of Chemical Engineering, Loughborough University, LoughboroughLE11 3TU, United Kingdom
| | - Goran T. Vladisavljević
- Department
of Chemical Engineering, Loughborough University, LoughboroughLE11 3TU, United Kingdom
| | - François Nadal
- Wolfson
School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, LoughboroughLE11 3TU, United Kingdom
| | - Cécile Cottin-Bizonne
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon 1—CNRS, Université de Lyon, Villeurbanne Cedex69622, France
| | - Christophe Pirat
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon 1—CNRS, Université de Lyon, Villeurbanne Cedex69622, France
| | - Guido Bolognesi
- Department
of Chemical Engineering, Loughborough University, LoughboroughLE11 3TU, United Kingdom
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8
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Composite Norland Optical Adhesive (NOA)/silicon flow focusing devices for colloidal particle manipulation and synthesis. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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9
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Shah PR, Tan H, Taylor D, Tang X, Shi N, Mashat A, Abdel-Fattah A, Squires TM. Temperature dependence of diffusiophoresis via a novel microfluidic approach. LAB ON A CHIP 2022; 22:1980-1988. [PMID: 35445222 DOI: 10.1039/d1lc00916h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The temperature dependence of the diffusiophoretic mobility (DDP) is investigated experimentally and compared with theoretical predictions. These systematic measurements were made possible by a new microfluidic approach that enables truly steady state gradients to be imposed, and direct and repeatable measurements of diffusiophoretic migration to be made over hours-long time scales. Diffusiophoretic mobilities were measured for fluorescent, negatively charged polystyrene particles under NaCl gradients, at temperatures ranging from 20 °C to 70 °C. Measured DDP values were found to increase monotonically with temperature, and to agree, both qualitatively and relatively quantitatively, with theoretical predictions based on electrophoretically-measured zeta potentials. These results provide confidence that existing diffusiophoresis theories can accurately predict DP mobilities over a range of temperatures. More broadly, we anticipate our new microfluidic approach will facilitate and enable new tests of diffusiophoretic phenomena under a wide range of physical and chemical conditions.
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Affiliation(s)
- Parth R Shah
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Huanshu Tan
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
| | - David Taylor
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Xiaoyu Tang
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Nan Shi
- EXPEC Advanced Research Center, Saudi Aramco, Dhahran 31311, Saudi Arabia
| | - Afnan Mashat
- EXPEC Advanced Research Center, Saudi Aramco, Dhahran 31311, Saudi Arabia
| | - Amr Abdel-Fattah
- EXPEC Advanced Research Center, Saudi Aramco, Dhahran 31311, Saudi Arabia
| | - Todd M Squires
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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10
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Shim S. Diffusiophoresis, Diffusioosmosis, and Microfluidics: Surface-Flow-Driven Phenomena in the Presence of Flow. Chem Rev 2022; 122:6986-7009. [PMID: 35285634 DOI: 10.1021/acs.chemrev.1c00571] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Diffusiophoresis is the spontaneous motion of particles under a concentration gradient of solutes. Since the first recognition by Derjaguin and colleagues in 1947 in the form of capillary osmosis, the phenomenon has been broadly investigated theoretically and experimentally. Early studies were mostly theoretical and were largely interested in surface coating applications, which considered the directional transport of coating particles. In the past decade, advances in microfluidics enabled controlled demonstrations of diffusiophoresis of micro- and nanoparticles. The electrokinetic nature and the typical scales of interest of the phenomenon motivated various experimental studies using simple microfluidic configurations. In this review, I will discuss studies that report diffusiophoresis in microfluidic systems, with the focus on the fundamental aspects of the reported results. In particular, parameters and influences of diffusiophoresis and diffusioosmosis in microfluidic systems and their combinations are highlighted.
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Affiliation(s)
- Suin Shim
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
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11
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Camargo M, González DL. Colloidal model of two-step protocol for epitaxial growth in one dimension. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:144006. [PMID: 35038680 DOI: 10.1088/1361-648x/ac4c14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
We explore the application of a two-step growth protocol to a one-dimensional colloidal model. The evolution of the system is described in terms of the time-dependence of both monomer and island densities,N1andN, while its structure is characterized by using distributions of the gap length, the capture zone, the inter-island distance, and the island length. Analytical results obtained from rate equations are compared with these from molecular dynamics simulations. Since the two-step growth protocol deals with nucleation and aggregation processes in two completely separated time regimes, it makes possible to gain better understanding and control on the island formation mechanism than the standard one-step protocol. The predicted features and advantages of the two-step process could be experimentally tested using deposition of colloidal spheres on pattern substrates.
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Affiliation(s)
- Manuel Camargo
- FIMEB & CICBA, Universidad Antonio Nariño-Campus Farallones, Km 18 via Cali-Jamundí, Cali, Colombia
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12
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Tan H, Banerjee A, Shi N, Tang X, Abdel-Fattah A, Squires TM. A two-step strategy for delivering particles to targets hidden within microfabricated porous media. SCIENCE ADVANCES 2021; 7:7/33/eabh0638. [PMID: 34389540 PMCID: PMC8363150 DOI: 10.1126/sciadv.abh0638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/25/2021] [Indexed: 06/01/2023]
Abstract
The delivery of small particles into porous environments remains highly challenging because of the low permeability to the fluids that carry these colloids. Even more challenging is that the specific location of targets in the porous environment usually is not known and cannot be determined from the outside. Here, we demonstrate a two-step strategy to deliver suspended colloids to targets that are "hidden" within closed porous media. The first step serves to automatically convert any hidden targets into soluto-inertial "beacons," capable of sustaining long-lived solute outfluxes. The second step introduces the deliverable objects, which are designed to autonomously migrate against the solute fluxes emitted by the targets, thereby following chemical trails that lead to the target. Experimental and theoretical demonstrations of the strategy lay out the design elements required for the solute and the deliverable objects, suggesting routes to delivering colloidal objects to hidden targets in various environments and technologies.
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Affiliation(s)
- Huanshu Tan
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106-5080, USA.
| | - Anirudha Banerjee
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106-5080, USA
| | - Nan Shi
- Saudi Aramco, EXPEC Advanced Research Center, Dhahran 31311, Saudi Arabia
| | - Xiaoyu Tang
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106-5080, USA
| | - Amr Abdel-Fattah
- Saudi Aramco, EXPEC Advanced Research Center, Dhahran 31311, Saudi Arabia
| | - Todd M Squires
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106-5080, USA.
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