Transparent Surface Acoustic Wave Technologies on glass to tackle soiling, icing, and fouling issues

Abstract

Surface acoustic wave (SAW) technology is widely used in microfluidics and sensing applications, for example, cell manipulation and sensing physical variables such as UV light, humidity, gas, and bio-sensing. SAWs can transport, pump, jet, and nebulise small volumes of liquids, cells, and microparticles for drug delivery and lab-on-a-chip applications. Piezoelectric materials such as zinc oxide (ZnO) are commonly used in thin film-based SAW devices.

Glass surfaces have encountered many challenges in various applications, including fouling and icing. Most solutions to these limitations have not always been practical because of high energy consumption or potential health and environmental issues. This project aims to show that transparent SAW devices based on ZnO thin films on glass substrates have great promise for applications such as cleaning optical components, ice and fog mitigation, and bacterial inactivation, which are crucial for many industry or biological applications. In this thesis, acoustofluidics performance of ZnO/glass SAW devices has been demonstrated for pumping, jetting, nebulisation, fogging, anti-icing, at different powers with hydrophobic coatings. These thin films SAW devices showed the ability to actively clean surfaces, prevent ice formation, and kill bacteria, through mechanisms of acoustic wave agitation, streaming, acoustic radiation, and localised thermal effects. Active and passive approaches were used to study the interactions of SAWs with bacteria and ZnO tetrapods, leading to bacterial inactivation. The combination of SAW, ZnO tetrapods, and detergent in a paste-like material inhibited bacterial growth.

Date of Award	3 Sept 2024
Original language	English
Awarding Institution	Northumbria University
Supervisor	Yongqing (Richard) Fu (Supervisor), Qiang Wu (Supervisor), Kunyapat Thummavichai (Supervisor), Yunhong Jiang (Supervisor) & Lynn Dover (Supervisor)