The project sought to
I. develop high precision nanotextured (<10 nm) surfaces with controlled nanomechanical properties
II. gain fundamental insights to how such nanoengineered surfaces can (i) delay ice formation and resist high-speed liquid impacts and (ii) protect against abrasion and corrosion.
A number of advances were made in order to deliver the three work packages (WPs) in the project.
First, we focussed on electrochemical anodization can achieve morphology control at the nanoscale, while using environment friendly electrolytes and etchants. This allowed us to investigate how safer chemicals can be used to achieve similar surface texture orecision as previously. The work was published as a journal article and a thorough book chapter.
Second, for further precision, surface grown metal-organic frameworks (MOFs) were introduced as sustainable, transparent, and amphiphobic (repels water as well as organic solvents) coatings. The approach enabled us to overcome issues such as avoiding use of per and polyfluoroalkyl substances (PFAS) which are known to have major health and environmental issues. These surfaces were also able to resist high-speed liquid impact (up to ∼35 m/s, typical of cars on a highway for example) and offered low ice adhesion (
https://doi.org/10.1021/acs.nanolett.1c00157(s’ouvre dans une nouvelle fenêtre)). Perhaps just as interestingly these surfaces offer a texture with hierarchy of nanoscale features. We call this nanohierarchical surfaces which have sub-nanometer scales pores. We also think that this surfaces may absorb pollutants directly from air. So far, we have demonstrated this by these surfaces absorbing water pollutants. The approach of highly precise nanoengineered surfaces was extended by using covalent organic frameworks (COFs), based coatings (
https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202302466(s’ouvre dans une nouvelle fenêtre)). These are chemical more stable and the precision allowed us to avoid ice formation down to -28C and scaling. We feel that these nano-precision, PFAS free surfaces should have fairly wide range of applications.
Third, we showed that by using flexible materials we can improve the robustness of liquid repellent surfaces. This is a principle that natural examples of liquid repellent surfaces such as butterfly wings or plant leaves inherently benefit from. The work was published in Nature Materials (
https://doi.org/10.1038/s41563-018-0044-2(s’ouvre dans une nouvelle fenêtre)) and we have now used it to make robust coatings with a wide variety of materials. This line of work led to an ERC Proof of Concept project around developing sustainable coatings for wind turbine blades. We are currently in the process of raising seed round to set-up a spin outcompany around sustainable, PFAS free coatings.
Fourth, we developed another nanocomposite which is simultaneously piezoelectric and piezocatalytic without requiring any poling step (i.e. self-poled). The films made of this material (
https://doi.org/10.1016/j.nanoen.2020.105339(s’ouvre dans une nouvelle fenêtre)) feature high power density (47.14 mW cm-3) subject to simple hand tapping and degrade harmful carcinogenic dyes (i.e. water pollutants with >90% within 20 min. This water remediation can happen in dark just with mechanical action, which is very different to light activated water remediation which relies on a source of light.
These innovations allowed us to team up with clinician to develop sensorised surgical gloves. These sensors are essentially similar to some of the nanocomposite coatings mentioned above. These are very inexpensive and we think they should enable safer surgeries. For example, we used such sensorised gloves to measure forces in real-time, during validated surgical tasks and other interventional applications. (10.1227/neu.0000000000002239). We are also investigating use of these sensors for helping to detect fetal orientation during labour (
https://www.bbc.co.uk/programmes/w3ct31zn(s’ouvre dans une nouvelle fenêtre))
