Behavior of Janus Particles at Liquid Interfaces

Volume 1D, Symposia: Transport Phenomena in Mixing; Turbulent Flows; Urban Fluid Mechanics; Fluid Dynamic Behavior of Complex Particles; Analysis of Elementary Processes in Dispersed Multiphase Flows; Multiphase Flow With Heat/Mass Transfer in Process Technology; Fluid Mechanics of Aircraft and Rocket Emissions and Their Environmental Impacts; High Performance CFD Computation; Performance of Multiphase Flow Systems; Wind Energy; Uncertainty Quantification in Flow Measurements and Simulations ◽

10.1115/fedsm2014-22144 ◽

2014 ◽

Author(s):

Hossein Rezvantalab ◽

Shahab Shojaei-Zadeh

Keyword(s):

Small Difference ◽

Separation Distance ◽

Janus Particles ◽

Interface Plane ◽

Fluid Interfaces ◽

Liquid Interfaces ◽

Ellipsoidal Particles ◽

Particle Force ◽

Energetic Interactions

We study the capillary-induced interactions and configuration of spherical and non-spherical Janus particles adsorbed at flat liquid-fluid interfaces. For Janus spheres, the equilibrium orientation results in each hemisphere being exposed to its more favored fluid. However, experimental observations suggest that some of these particles may take a tilted orientation at the interface, giving rise to a deformed interface. On the other hand, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt even at equilibrium. The overlap of deformed menisci results in energetic interactions between neighboring particles. We numerically calculate the interface shape around the particles by minimizing the total surface energy of the system comprising of the interface and particle-fluid regions. We quantify these interactions through evaluation of capillary energy variation as a function of the orientation and separation distance between the particles. We find that Janus spheres with similar orientations undergo a relative realignment in the interface plane in order to minimize the capillary energy. In case of ellipsoidal particles, the particles assemble in a preferred side-by-side configuration. We evaluate the role of anisotropy and degree of amphiphilicity on the inter-particle force and the capillary torque. The results can be used to predict the migration and oriented assembly of Janus particles with various geometrical and surface properties at liquid-fluid interfaces.

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Janus Particles at Fluid Interfaces: Stability and Interfacial Rheology

Nanomaterials ◽

10.3390/nano11020374 ◽

2021 ◽

Vol 11 (2) ◽

pp. 374

Author(s):

Elton L. Correia ◽

Nick Brown ◽

Sepideh Razavi

Keyword(s):

Colloidal Particles ◽

Janus Particles ◽

Shear Stresses ◽

Fluid Interfaces ◽

Interfacial Rheology ◽

Pickering Emulsions ◽

Interfacial Mechanics ◽

Anisotropic Surface ◽

Particle Anisotropy

The use of the Janus motif in colloidal particles, i.e., anisotropic surface properties on opposite faces, has gained significant attention in the bottom-up assembly of novel functional structures, design of active nanomotors, biological sensing and imaging, and polymer blend compatibilization. This review is focused on the behavior of Janus particles in interfacial systems, such as particle-stabilized (i.e., Pickering) emulsions and foams, where stabilization is achieved through the binding of particles to fluid interfaces. In many such applications, the interface could be subjected to deformations, producing compression and shear stresses. Besides the physicochemical properties of the particle, their behavior under flow will also impact the performance of the resulting system. This review article provides a synopsis of interfacial stability and rheology in particle-laden interfaces to highlight the role of the Janus motif, and how particle anisotropy affects interfacial mechanics.

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Multiple interactions in riverine biofilms - surfactant adsorption, bacterial attachment and biodegradation

Water Science & Technology ◽

10.2166/wst.1995.0015 ◽

1995 ◽

Vol 31 (1) ◽

pp. 61-70 ◽

Cited By ~ 6

Author(s):

Graham F. White

Keyword(s):

Organic Pollutants ◽

Bacterial Attachment ◽

Solid Surfaces ◽

Sediment Surface ◽

Liquid Interfaces ◽

Polluted Soils ◽

Biofilm Bacteria ◽

The Impact ◽

Multiple Interactions

Many organic pollutants, especially synthetic surfactants, adsorb onto solid surfaces in natural and engineered aquatic environments. Biofilm bacteria on such surfaces make major contributions to microbial heterotrophic activity and biodegradation of organic pollutants. This paper reviews evidence for multiple interactions between surfactants, biodegradative bacteria, and sediment-liquid interfaces. Biodegradable surfactants e.g. SDS, added to a river-water microcosm were rapidly adsorb to sediment surface and stimulated the indigenous bacteria to attach to the sediment particles. Recalcitrant surfactants and non-surfactant organic nutrients did not stimulate attachment Attachment of bacteria was maximal when biodegradation was fastest, and was reversed when biodegradation was complete. Dodecanol, the primary product of SDS-biodegradation, markedly stimulated attachment. When SDS was added to suspensions containing sediment and either known degraders or known non-degraders, only the degraders became attached, and attachment accelerated surfactant biodegradation to dodecanol. These cyclical cooperative interactions have implications for the design of biodegradability-tests, the impact of surfactant adjuvants on biodegradability of herbicides/pesticides formulated with surfactants, and the role of surfactants used to accelerate bioremediation of hydrocarbon-polluted soils.

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Substrate wettability guided oriented self assembly of Janus particles

Scientific Reports ◽

10.1038/s41598-020-80760-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Meneka Banik ◽

Shaili Sett ◽

Chirodeep Bakli ◽

Arup Kumar Raychaudhuri ◽

Suman Chakraborty ◽

...

Keyword(s):

Self Assembly ◽

Janus Particles ◽

Water Molecules ◽

Functional Coatings ◽

Hexagonal Close Packed ◽

Local Densities ◽

Inhomogeneous Properties ◽

Metal Polymer ◽

Specific Orientation

AbstractSelf-assembly of Janus particles with spatial inhomogeneous properties is of fundamental importance in diverse areas of sciences and has been extensively observed as a favorably functionalized fluidic interface or in a dilute solution. Interestingly, the unique and non-trivial role of surface wettability on oriented self-assembly of Janus particles has remained largely unexplored. Here, the exclusive role of substrate wettability in directing the orientation of amphiphilic metal-polymer Bifacial spherical Janus particles, obtained by topo-selective metal deposition on colloidal Polymestyere (PS) particles, is explored by drop casting a dilute dispersion of the Janus colloids. While all particles orient with their polymeric (hydrophobic) and metallic (hydrophilic) sides facing upwards on hydrophilic and hydrophobic substrates respectively, they exhibit random orientation on a neutral substrate. The substrate wettability guided orientation of the Janus particles is captured using molecular dynamic simulation, which highlights that the arrangement of water molecules and their local densities near the substrate guide the specific orientation. Finally, it is shown that by spin coating it becomes possible to create a hexagonal close-packed array of the Janus colloids with specific orientation on differential wettability substrates. The results reported here open up new possibilities of substrate-wettability driven functional coatings of Janus particles, which has hitherto remained unexplored.

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Three-particle quantization condition in a finite volume: 1. The role of the three-particle force

Journal of High Energy Physics ◽

10.1007/jhep09(2017)109 ◽

2017 ◽

Vol 2017 (9) ◽

Cited By ~ 56

Author(s):

Hans-Werner Hammer ◽

Jin-Yi Pang ◽

Akaki Rusetsky

Keyword(s):

Finite Volume ◽

Quantization Condition ◽

Particle Force

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Surface activity of Janus particles adsorbed at fluid–fluid interfaces: Theoretical and experimental aspects

Advances in Colloid and Interface Science ◽

10.1016/j.cis.2015.06.002 ◽

2016 ◽

Vol 233 ◽

pp. 240-254 ◽

Cited By ~ 34

Author(s):

Miguel Angel Fernandez-Rodriguez ◽

Miguel Angel Rodriguez-Valverde ◽

Miguel Angel Cabrerizo-Vilchez ◽

Roque Hidalgo-Alvarez

Keyword(s):

Surface Activity ◽

Janus Particles ◽

Fluid Interfaces

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Experimental insight on the role of forced flow velocity and separation distance on reverse smoldering

Aeronautics and Aerospace Open Access Journal ◽

10.15406/aaoaj.2018.02.00073 ◽

2018 ◽

Vol 2 (6) ◽

pp. 414-422

Author(s):

Vinayak Malhotra ◽

Rakshantha M ◽

Bunny Venkat Y

Keyword(s):

Flow Velocity ◽

Separation Distance ◽

Forced Flow

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Capillary interactions between spherical Janus particles at liquid–fluid interfaces

Soft Matter ◽

10.1039/c3sm27380f ◽

2013 ◽

Vol 9 (13) ◽

pp. 3640 ◽

Cited By ~ 40

Author(s):

Hossein Rezvantalab ◽

Shahab Shojaei-Zadeh

Keyword(s):

Janus Particles ◽

Fluid Interfaces ◽

Capillary Interactions

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Magneto-capillary dynamics of amphiphilic Janus particles at curved liquid interfaces

Soft Matter ◽

10.1039/c8sm00518d ◽

2018 ◽

Vol 14 (23) ◽

pp. 4661-4665 ◽

Cited By ~ 12

Author(s):

Wenjie Fei ◽

Michelle M. Driscoll ◽

Paul M. Chaikin ◽

Kyle J. M. Bishop

Keyword(s):

Magnetic Particles ◽

Janus Particles ◽

Liquid Interfaces ◽

Capillary Dynamics

Static homogeneous fields drive motions of magnetic particles along curved liquid interfaces.

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Adsorption of surfactants at solid/liquid interfaces

Surfactants ◽

10.1093/oso/9780198828600.003.0007 ◽

2019 ◽

pp. 130-155

Author(s):

Bob Aveyard

Keyword(s):

Strong Influence ◽

Langmuir Equation ◽

Solid Surfaces ◽

Polymeric Surfactant ◽

Fluid Interfaces ◽

Liquid Interfaces ◽

Free Energies ◽

Micellar Aggregates ◽

Diffuse Part ◽

Solid Liquid

The physical properties of solid/liquid interfaces are more diverse than those of liquid/fluid interfaces, and consequently the interactions giving rise to adsorption of surfactant or polymeric surfactant are more varied. Solid surfaces can be either hydrophilic or hydrophobic, the former being water-wetted and containing polar or ionogenic sites. Electrical charge at the solid surface is neutralized by ions in the inner and outer Helmholtz planes and in the diffuse part of the electrical double layer. Surface charge has a strong influence on adsorption of ionic surfactants. Standard free energies of surfactant adsorption are obtained by use of an appropriate adsorption isotherm such as the Stern–Langmuir equation. Micellar aggregates of various shapes and sizes can also form at solid/liquid interfaces.

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