scholarly journals Nonaffine deformation and tunable yielding of colloidal assemblies at the air–water interface

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18343-18351 ◽  
Author(s):  
Armando Maestro ◽  
Alessio Zaccone
Keyword(s):  
Theoretical Model ◽  
Shear Deformation ◽  
Colloidal Nanoparticles ◽  
Fluid Interfaces ◽  
Water Interface ◽  
Air Water Interface ◽  
Nonaffine Deformation

A theoretical model that explains the deformation of colloidal nanoparticles assembled at fluid interfaces under shear deformation.

scholarly journals Soft electrostatic repulsion in particle monolayers at liquid interfaces: surface pressure and effect of aggregation

2016 ◽  
Vol 374 (2072) ◽  
pp. 20150130 ◽  
Author(s):  
Peter A. Kralchevsky ◽  
Krassimir D. Danov ◽  
Plamen V. Petkov
Keyword(s):  
Theoretical Model ◽  
Surface Pressure ◽  
Charged Particles ◽  
Interparticle Distance ◽  
Electrostatic Repulsion ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Polar Fluid ◽  
Air Water Interface ◽  
Oil Water

Non-densely packed interfacial monolayers from charged micrometre-sized colloid particles find applications for producing micropatterned surfaces. The soft electrostatic repulsion between the particles in a monolayer on an air/water (or oil/water) interface is mediated by the non-polar fluid, where Debye screening is absent and the distances between the particles are considerably greater than their diameters. Surface pressure versus area isotherms were measured at the air/water interface. The experiments show that asymptotically the surface pressure is inversely proportional to the third power of the interparticle distance. A theoretical model is developed that predicts not only the aforementioned asymptotic law but also the whole surface pressure versus area dependence. An increase in the surface pressure upon aggregation of charged particles in the interfacial monolayers is experimentally established. This effect is explained by the developed theoretical model, which predicts that the surface pressure should linearly increase with the square root of the particle mean aggregation number. The effect of added electrolyte on the aggregation is also investigated. The data lead to the conclusion that ‘limited aggregation’ exists in the monolayers of charged particles. In brief, the stronger electrostatic repulsion between the bigger aggregates leads to a higher barrier to their coalescence that, in turn, prevents any further aggregation, i.e. negative feedback is present. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.

scholarly journals Photoswitching the mechanical properties in Langmuir layers of semifluorinated alkyl-azobenzenes at the air–water interface

2015 ◽  
Vol 17 (43) ◽  
pp. 28844-28852 ◽  
Author(s):  
Antigoni Theodoratou ◽  
Ulrich Jonas ◽  
Benoit Loppinet ◽  
Thomas Geue ◽  
René Stangenberg ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Light Stimulus ◽  
Fluid Interfaces ◽  
Water Interface ◽  
Structure And Dynamics ◽  
Air Water Interface

Manipulation of the structure and dynamics of semifluorinated alkyl-azobenzene layers at the air–water interface by an external light stimulus suggests ways of tailoring responsive fluid interfaces.

scholarly journals A theoretical model of Surtseyan bomb fragmentation

2021 ◽  
Vol 477 (2253) ◽  
pp. 20210166
Author(s):  
Emma Greenbank ◽  
Mark J. McGuinness ◽  
C. Ian Schipper
Keyword(s):  
Mathematical Model ◽  
Theoretical Model ◽  
High Pressures ◽  
Volcanic Eruptions ◽  
Steam Pressure ◽  
Water Interface ◽  
Important Class ◽  
Air Water Interface ◽  
Flow Through ◽  
The 1960S

Surtseyan eruptions are an important class of mostly basaltic volcanic eruptions first identified in the 1960s, where erupting magma at an air–water interface interacts with large quantities of slurry, a mixture of previously ejected tephra that re-enters the crater together with water. During a Surtseyan eruption, hot magma bombs are ejected that initially contain pockets of slurry. Despite the formation of steam and anticipated subsequent high pressures inside these bombs, many survive to land without exploding. We seek to explain this by building and solving a simplified spherical mathematical model that describes the coupled evolution of pressure and temperature due to the flashing of liquid to vapour within a Surtseyan bomb while it is in flight. Analysis of the model provides a criterion for fragmentation of the bomb due to steam pressure build-up, and predicts that if diffusive steam flow through the porous bomb is sufficiently rapid the bomb will survive the flight intact. This criterion explicitly relates fragmentation to bomb properties, and describes how a Surtseyan bomb can survive in flight despite containing flashing liquid water, contributing to an ongoing discussion in volcanology about the origins of the inclusions found inside bombs.

scholarly journals Multistable interaction between a spherical Brownian particle and an air–water interface

Soft Matter ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 960-969
Author(s):  
Stefano Villa ◽  
Antonio Stocco ◽  
Christophe Blanc ◽  
Maurizio Nobili
Keyword(s):  
Brownian Particle ◽  
Fluid Interfaces ◽  
Water Interface ◽  
Air Water Interface

A novel multi-stable interaction between microparticles and fluid interfaces is measured pointing out the still unaccounted role of surface heterogeneities.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

Sign in / Sign up

Export Citation Format

Share Document