Highly ordered monolayer formation of silica beads assisted by ultra-sound and microscopic barrier at air/water interface

We fabricated closely packed monolayer of hydrophobically modified non-porous silica (NPS) beads at air/water interface. Hydrophilic silica beads were modified by hydrocarbon that render hydrophobic on their surface. Ultra-sound applied to the water subphase, inducing large scaled two-dimensional ordering of the beads by reducing three-dimensional irregular cluster formations while spreading solvent evaporated. Furthermore, surface pressure generated by polymeric surface micelle effectively pushes the silica beads and reduces voids between the 2D silica clusters.