External Control of Liquid Nanofilms for Switchable Friction and Adhesion

Información del proyecto

LIQUISWITCH

Identificador del acuerdo de subvención: 676861

DOI

10.3030/676861

Proyecto cerrado

Fecha de la firma de la CE 1 Febrero 2016

Fecha de inicio 1 Abril 2016

Fecha de finalización 30 Septiembre 2021

Financiado con arreglo a

• EXCELLENT SCIENCE - European Research Council (ERC)

Coste total

€ 1 492 828,00

Aportación de la UE

€ 1 492 828,00

Coordinado por

THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
United Kingdom

Periodic Reporting for period 4 - LIQUISWITCH (External Control of Liquid Nanofilms for Switchable Friction and Adhesion)

Período documentado: 2020-10-01 hasta 2021-09-30

Resumen del contexto y de los objetivos generales del proyecto

Many of the natural and technological materials we encounter in life have important characteristics defined by their surface or interface. For example our sense of touch mostly relies on the mechanical characteristics of the surface of objects; and new technologies exploit interfaces such as the finely tuned electrical properties of the touch-screens on mobile devices. Surfaces and interfaces have been studied for many years, but less understood is the role of thin liquid films on solid materials or confined between two solid materials. These thin liquid films – which are ubiquitous in atmospheric conditions – can drastically alter the surface characteristics. From our common experience we know that dry sand runs freely whereas a small amount of water causes sand to hold its shape; and small amounts of oil are effective in lubricating mechanical parts. With this project the aim is to transform these well-known and ‘passive’ effects of thin liquid films into an ‘active’ technology for switching material properties. The work is fundamental in nature and aimed at understanding the underpinning concepts required to make this work: we are building delicate instruments to measure and characterise thin liquid films and to apply controlled electric fields across them. The results are anticipated to provide detailed understanding of the basic science required to control and switch surface interactions using external fields.

Trabajo realizado desde el comienzo del proyecto hasta el final del período abarcado por el informe y los principales resultados hasta la fecha

Our first objective was to build instruments capable of applying well-controlled electric fields across liquid films, and at the same time measure with high accuracy the thickness and other (optical, mechanical) properties of the liquid films. We have now succeeded in constructing several versions of this apparatus, and have published papers reporting the details of how it works so that other scientists could make similar measurements in future. Along the way, and while carrying out control experiments, we have discovered some unanticipated behaviours of the liquid films, particularly liquid containing high concentrations of ions (salt). We continue to investigate the detailed origins of the behaviour in order to better understand the properties of liquids.

Avances que van más allá del estado de la técnica e impacto potencial esperado (incluida la repercusión socioeconómica y las implicaciones sociales más amplias del proyecto hasta la fecha)

We have progressed beyond the state of the art in terms of the instruments built and reported (see publications in Review of Scientific Instruments between 2016-18), and the discovery of previously-unknown forces and screening of electric fields in highly concentrated electrolytes (publications from 2016-18 in J. Phys. Chem. Letters, Faraday Discussions, and Physical Review Letters).
The expected results by the end of the project include reports of switching liquid film properties using electric fields, and a full analysis of the field-screening properties in electrolytes.

Diagram of the adhesion switching apparatus and measurement