Capillary-driven binding of thin triangular prisms at fluid interfaces

Abstract

We observe capillary-driven binding between thin, equilateral triangular prisms at a flat air-water interface. The edge length of the equilateral triangle face is 120 μm, and the thickness of the prism is varied between 2 and 20 μm. For thickness to length (T/L) ratios of 1/10 or less, pairs of triangles preferentially bind in either tip-to-tip or tip-to-midpoint edge configurations; for pairs of prisms of thickness T/L = 1/5, the tip of one triangle binds to any position along the other triangle's edge. The distinct binding configurations for small T/L ratios result from physical bowing of the prisms, a property that arises during their fabrication. When bowed prisms are placed at the air-water interface, two distinct polarity states arise: prisms either sit with their center of mass above or below the interface. The interface pins to the edge of the prism's concave face, resulting in an interface profile that is similar to that of a capillary hexapole, but with important deviations close to the prism that enable directed binding. We present corresponding theoretical and numerical analysis of the capillary interactions between these prisms and show how prism bowing and contact-line pinning yield a capillary hexapole-like interaction that results in the two sets of distinct, highly-directional binding events. Prisms of all T/L ratios self-assemble into space-spanning open networks; the results suggest design parameters for the fabrication of building blocks of ordered open structures such as the Kagome lattice.

Shape-Anisotropic Colloids at Interfaces

“…In the case of ellipsoidal and cylindrical particles of similar wettability (i.e., both hydrophilic), a capillary charge reversal is observed. ,, The reversal of capillary charges is also observed when the wettability of the ellipsoidal and cylindrical particles changes from hydrophilic to hydrophobic. ,,,, Thus, both shape and wettability changes can lead to capillary charge reversal. The other particle shapes whose interface deformations are investigated include 3D printed objects with different branch curvatures, equilateral triangular prisms of different thickness, and thermo­responsive soft-programmed gel particles (SPGPs) . The interface profiles based on theoretical calculations and simulations support the experimental observations, i.e., quadrupolar-type ,,, deformation for ellipsoids/cylinders and octupolar-type ,,, deformation for cuboidal particles.…”

“…The interface profiles based on theoretical calculations and simulations support the experimental observations, i.e., quadrupolar-type ,,, deformation for ellipsoids/cylinders and octupolar-type ,,, deformation for cuboidal particles. The Surface Evolver simulations have been used extensively to investigate various aspects of particle-laden interfaces such as the wetting behavior, interface deformation, capillary bridge formation, and resulting particle assemblies. ,, …”

“…In another study, the capillary assembly of branched millimeter-scale objects at the air–water interface shows various mesoscopic structures that can be controlled by subtle changes in particle morphology . In a recent study, the interfacial adsorption and assembly of thin equilateral triangular prisms of varying thickness at the air–water interface are investigated . When adsorbed at the air–water interface, the triangular prisms occupy different equilibrium positions and induce a hexapolar-type deformation that directs the assembly of neighboring prisms.…”

Janus Particles at Fluid Interfaces: Stability and Interfacial Rheology

“…The interfacial distortions can originate from the weight of particles (gravity-driven capillary attraction for heavier or bigger particles) [162] or electrostatic stresses caused by the particles dipolar field (electrodipping) [158,163]. In addition, surface roughness, chemical inhomogeneity, and shape anisotropy of particles cause the meniscus to take an irregular shape over the particle surface in order to satisfy the correct contact angle at all points along the perimeter, as shown in Figure 3d [152,[164][165][166][167][168]. The attractive force between two particles at a separation distance of r is shown to scale as F ∼ r −5 , which is especially consequential in case of heterogeneous particles [139,[167][168][169][170].…”

Boric Acid (H3(BO3): Recognize The Molecular Interactions in Solutions

“…Asam Borat memiliki bentuk molekul (125) segitiga datar (126)(127)(128)(129)(130) dengan momen dipol (131) nol. Molekul (132) dikatakan bersifat polar (133) jika memiliki momendipol >0 atau ≠0 dan dikatakan non polar (134) jika momen dipolnya 0.…”