Oscillating endoskeletal antibubbles

TL;DR

This study investigates how endoskeletal structures within antibubbles influence their oscillation response to ultrasound, revealing that the endoskeleton dampens oscillation amplitude, which is relevant for biomedical and industrial applications.

Contribution

It provides the first experimental analysis of how endoskeletal structures affect antibubble oscillations under ultrasound exposure.

Findings

Endoskeletons dampen antibubble oscillations.

Ultrasound response differs between antibubbles with and without endoskeletons.

High-speed microscopy captures detailed oscillation behavior.

Abstract

An antibubble is a gas bubble with a liquid droplet inside. Antibubbles have a potential role in ultrasonic imaging, ultrasound-guided drug delivery, and hydrocarbon leakage detection. The liquid core droplets inside antibubbles can be stabilised with a process called Pickering stability. Other systems proposed include spoke crystals to suspend the droplet or endoskeletal structures. In this study, the oscillatory response of microscopic endoskeletal antibubbles to ultrasound has been investigated, primarily to determine whether the presence of an endoskeleton attenuates the oscillation amplitude of the antibubble. Three emulsions containing (anti)bubbles were prepared for evaluation. Each emulsion was pipetted into the observation chamber of a high-speed microscopic observation system. A high-speed camera, operating at 10 million frames per second, was couples to the microscope. During camera recording, the materials were subjected to ultrasound pulses from a laboratory-assembled single-element transducer. The presence of an endoskeleton with droplets hampers the oscillation of antibubbles as compared to identical bubbles without endoskeleton and droplet content.