Aqueous Bubbles\nStabilized with Millimeter-Sized Polymer\nPlates

Abstract

(Sub)millimeter-sized hexagonal polymer plates that were\nmonodisperse\nin shape and size were utilized as stabilizers for aqueous bubbles,\nand the effects of the hydrophilic–hydrophobic property, size,\nand solid concentration of the plates on the formability, stability,\nand shape and structure of aqueous bubbles were investigated. The\nformability and stability of the bubbles were improved by increasing\nthe hydrophobicity of the plate surface, decreasing the plate size,\nand increasing the solid concentration of the plates. For plates with\nsuitable water wettability, three-dimensional bubbles with nearly\nspherical and polyhedral shapes were formed by the adsorption of plates\nto the bare air bubbles introduced into the continuous water phase\nby air–water mixing. On the contrary, two-dimensional bubbles\nwith accordion-type structures consisting of alternating layers of\nplates and entrapped air bubbles were formed by the transfer of multiple\nplates with poor wettability from the air phase to the water phase\nby air–water mixing. Furthermore, a correlation was found between\nthe bubble/stabilizer size ratio and bubble shape for plates with\nthe suitable wettability: bubbles with nearly spherical shapes were\nformed when the bubble/plate size ratios were >2, bubbles with\nhexahedral,\npentahedral, and tetrahedral shapes were formed when the size ratios\nwere approximately 1, and bubbles with triangular and sandwich shapes\nwere formed when the size ratios were <0.8. Additionally, bubbles\nwith similar shapes were formed when the bubble/plate size ratios\nwere close, even when the sizes of the plates and bubbles were different.