Foam and cluster structure formation by latex particles at the air/water interface

Structural optimization of model colloidal clusters at the air–water interface using genetic algorithms

“…10 shows the sketch of a cluster structure observed in a video image of the interfacial colloid cluster shown in Fig. 2 of [1], and Fig. 1 of [3].…”

“…In order to explain the formation of these meso-structures, Ruiz-Garcia et al [1,2] used a simple DLVO [7] inter-particle interaction and determined the equilibrium cluster size assuming three macroscopic energies, the particle-particle electrostatic energies, the line tension along the perimeter of cluster, and the cluster-cluster interaction. Ghezzi and Earnshaw [3], on the other hand, have analyzed the microscopic inter-particle potential in more detail using DLVO force as well as dipolar and capillary force.…”

“…For example, instead of flocculation and sedimentation in the bulk solvent, the stable clusters and various macro structures appear at the surface, which is attributed to the colloid-colloid attraction. Recent experimental studies of Ruiz-Garcia et al [1,2], and Ghezzi and Earnshaw [3,4] revealed spontaneous formation of loosely bounded ordered structure in colloidal mono-layer trapped at the air-water interface. These include clusters that consist of several colloidal particles, a fragment of two-dimensional crystals, large voids within an extended two-dimensional structure which resembles foams, etc.…”

Predicting the Phase Diagram of Two-Dimensional Colloidal Systems with Long-Range Interactions

“…This unexpected attraction has been observed in systems of latex spheres trapped between glass plates 4 or at fluid-fluid interfaces. [5][6][7][8] For colloidal systems trapped between glass plates, the particles repel each other electrostatically through a Yukawatype potential. If the separation of the walls is small enough to restrict the movement of the particles to a plane, a secondary minimum in the micrometer range of the pair interaction potential is formed.…”

“…[5][6][7]9,10 The formation of these patterns cannot be explained solely on the basis of repulsive interactions. We have recently measured the pair interaction potential at low particle surface density, 11 and indeed the potential shows a secondary minimum in the micrometer range, similar to those found in colloidal systems trapped between glass plates.…”