Light-Driven Spatiotemporal Pickering Emulsion Droplet Manipulation Enabled by Plasmonic Hybrid Microgels

Guan, Xin; Cheng, Guangyao; Ho, Yi Ping; Binks, Bernard P.; Ngai, To

Abstract

The past decades have witnessed the development of various stimuli-responsive materials with tailored functionalities, enabling droplet manipulation through external force fields. Among different strategies, light exhibits excellent flexibility for contactless control of droplets, particularly in three-dimensional space. Here, we present a facile synthesis of plasmonic hybrid microgels based on the electrostatic heterocoagulation between cationic microgels and anionic Au nanoparticles. The hybrid microgels are effective stabilizers of oil-in-water Pickering emulsions. In addition, the laser irradiation on Au nanoparticles creats a “cascade effect” to thermally responsive microgels, which triggers a change in microgel wettability, resulting in microgel desorption and emulsion destabilization. More importantly, the localized heating generated by a focused laser induces the generation of a vapor bubble inside oil droplets, leading to the formation of a novel air-in-oil-in-water (A/O/W) emulsion. These A/O/W droplets are able to mimic natural microswimmers in an aqueous environment by tracking the motion of a laser spot, thus achieving on-demand droplet merging and chemical communication between isolated droplets. Such proposed systems are expected to extend the applications of microgel-stabilized Pickering emulsions for substance transport, programmed release and controlled catalytic reactions.

Citation

Guan, X., Cheng, G., Ho, Y. P., Binks, B. P., & Ngai, T. (2023). Light-Driven Spatiotemporal Pickering Emulsion Droplet Manipulation Enabled by Plasmonic Hybrid Microgels. Small, 19(47), Article 2304207. https://doi.org/10.1002/smll.202304207

• Journal Article Type: Article
• Acceptance Date: Oct 19, 2022
• Online Publication Date: Jul 25, 2023
• Publication Date: Nov 22, 2023
• Deposit Date: Feb 18, 2024
• Publicly Available Date: Feb 22, 2024
• Journal: Small
• Print ISSN: 1613-6810
• Electronic ISSN: 1613-6829
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 19
• Issue: 47
• Article Number: 2304207
• DOI: https://doi.org/10.1002/smll.202304207
• Keywords: Light-driven droplet manipulation; Photothermal effect; Pickering emulsion; Plasmonic hybrid microgels
• Public URL: https://hull-repository.worktribe.com/output/4348686