In Situ High-Speed Electrochemical Sensing of Surface Cleaning

Cleaning at a solid/liquid interface plays a vital role in many human activities. Whether this is in the food industry, the fabrication of electronic components, sterilisation of instrumentation in the healthcare sector or as a basic hygiene requirement, the same issue occurs: how to clean the material involved in an efficient manner but without degrading or damaging it? As such, many technological approaches have been developed. Amongst the many techniques employed to clean surfaces, ultrasonic systems (like cleaning baths) have many appealing qualities. This technology uses the action of bubbles driven by sound to clean an interface. Ultimately it is the interaction of sound and bubbles that is thought to drive the cleaning action although the exact mechanism may vary depending on the conditions employed. Cavitation is certainly a key factor, as the unusual physical as well as the chemical effects (the production of strong oxidants for example) are useful in this role. Ultrasonic cleaning has the advantage that it is relatively simple to deploy with the ubiquitous ultrasonic cleaning bath common in many academic, medical, industrial, and even domestic environments. However, there are technological limitations in all cleaning systems. Critical to the assessment and development of any cleaning technology for a particular substrate is a measure of 'how clean is it?' and 'is the cleaning system benign?'. Here recesses and in particular those that need further modification (through electroplating, for example) are pertinent. For example, if ultrasonic cleaning of a recess is invoked, how far into the recess has been cleaned and are there residual bubbles which may inhibit further critical treatment of the structure? In order to address these issues, this project will utilise a set of well controlled experiments designed to understand the important factors which come into play during cleaning. These sensing strategies will be based on new sensitive systems with the ultimate aim of producing a prototype deployable sensor for cleaning assessment within a range of commercial and academic environments.