Reversible Bubble Transfer on a Bioinspired Tridirectionally Anisotropic Lubricant-Infused Surface

Underwaterbubble transfers on functional surfaces with specialwettability have important research value for many fields such aswater purification, gas-evolving electrochemistry, heterogeneous catalysis,etc. However, realizing multi-interface collaborated and multi-directionalbubble transfers are still challenging. Herein, inspired by butterflywings, pitcher plants, and rice leaves, we present a tridirectionallyanisotropic lubricant-infused surface (TALIS) with micro-nanohierarchical step-like structures that are covered with silicone oil.The TALIS exhibits significant tridirectional anisotropy in termsof bubble sliding, specifically, the slippery property parallel tothe grooves with an ultra-low bubble sliding angle (BSA) of & SIM;2 & DEG;,and the unidirectional wettability perpendicular to the grooves withBSA difference of & SIM;48 & DEG; result from the step-edge pinningeffect. By adjusting the step height and width, TALISs with differenttridirectionally anisotropic wettability and stable bubble-holdingefficiency (& SIM;0.4 mg/cm(2)) are obtained. In addition,horizontal and anti-buoyancy unidirectional bubble transfers are realizedby collaborative squeezing of two face-to-face TALISs. By adjustingthe distance between the two TALISs, bubbles can be reversibly transferredbetween the two interfaces by multi-interfaces collaboration. Thiswork opens a new avenue to understand the bubble behaviors on functionalinterfaces with anisotropic wettability and provides a method to realizecontrollable bubble transfer on multi directions.

Automated summary

This study presents a tridirectionally anisotropic lubricant-infused surface (TALIS) with micro-nanohierarchical step-like structures inspired by butterfly wings, pitcher plants, and rice leaves. The TALIS exhibits significant tridirectional anisotropy in terms of bubble sliding and wettability, and enables controllable bubble transfer on multiple directions.