The research interests of the Mills group are wide and varied including: dye and semiconductor photochemistry, redox catalysis (in particular, oxygen catalysis), solar energy conversion (in particular artificial photosynthesis) and colour and fluorescence based indicators and smart inks and plastic films.
Photocatalyst Activity Indicator Inks (Paii’s) are now featured on Wikipedia. The inks were pioneered by the Mills group over a number years, and development of newer, improved ‘smart inks’ for detecting the activity of photocatalytic surfaces is ongoing.
A paper, published by the Mills group on November 14th, 2013, detailing a proposed ISO standard test for the testing of the activity of self-cleaning surfaces using a simple, inexpensive method, has been receiving considerable interest within the scientific community. The article, available via the link below, has been downloaded 667 times since its publication, with the most interest coming from the UK, US, India, China and Germany.
The article is available for download from:
Professor Mills and Dr Lawrie recently traveled to Seattle to engage with a company, Sensor Medical Technology. We met with members of the company, academia and patent lawyers in order to kick-start a new collaborative project to develop indicators for medical devices.
With the aid of travel funding awarded by the RSC, Dr Katherine Lawrie attended the world’s leading conference on optical sensors to present a poster on her work entitled ‘UV dosimetry for solar water disinfection (SODIS)’. The conference itself attracted 220 participants from 37 countries, bringing together engineers and scientists to discuss the recent progress and future trends in the design, fabrication, and application of optical sensing devices.
Wednesday March 19th was Green Impact “Platinum day” in the School of Chemistry and Chemical Engineering. After attaining a green impact gold award for our lab last year, all those in the school with gold awards came together to build on these awards and bring them beyond the localised effect of the lab, producing a series of events culminating in an “Environmental Communication Day with a Social Conscience”. During the day everyone in the school was invited to make their own smoothie (powered by a bicycle), participate in a treasure hunt and taste delights from around the world at a coffee morning which was contributed to by those of the many nationalities represented within the school. There were also a further two apple trees planted in the open quad area in the middle of the school, and the day ended with a quiz and environmental talks by Prof Martin Atkins and our very own Dr Katherine Lawrie. Katherine highlighted the work of the Mills group over the past few years which has gone some way to tackle environmental and humanitarian issues.
A novel approach to polymeric Ru(II)-diimine luminescent O2 sensors is described. The Ru(II)-diimine, tris (4,7-diphenyl-1,10-phenanthroline) ruthenium (II) dichloride ([Ru(dpp)3]2+), is first ion-paired to the surface of heterogeneous TiO2 particles, rendered negatively charged due to the alkali nature of the aqueous solution, to produce an O2 sensitive pigment with a strikingly high oxygen sensitivity (i.e. PO2 (S=1/2) = 0.002 atm, where PO2 (S=1/2) is defined as the amount of oxygen required to reduce the initial, oxygen free luminescence by 50%), and a rapid response to oxygen. The pigment is extruded in low density polyethylene (LDPE) to produce a thin (60 µm), flexible, O2 sensing plastic film, with an O2 sensitivity (PO2 (S=1/2) = 0.84 atm) comparable to the more traditional homogeneous lumophore ion-pair based O2 sensor ink films reported in the literature.
this is an open access article and can be downloaded free of charge from: http://pubs.rsc.org/en/Content/ArticleLanding/2013/AN/c3an01141k#!divAbstract
Three undergraduate students from Queen’s University of Belfast were granted summer studentships within the group, and worked on a variety of projects during their time here. Here’s what they have to say:
‘We spent the summer with the group assisting in research on photosensitive dyes. We mainly did work on the following:
– Testing photocatalytic indicator inks on a variety of active surfaces and testing prototype inks
– Modifying the formulation of inks to be used in marker pens, and producing pens featuring photocatalyst test inks. The pens provide a convenient way of applying ink to a photocatalytic surface to test its activity.
– Work with indicator dyes in development for the SODIs project. The project involves the use of solar energy to disinfect water. The inks can be used to show when the water has received enough UV light to be sterilised.
We really enjoyed the experience, and look forward to putting the skills we learnt into practice in our future studies’.
The 4th International Conference on Semiconductor Photochemistry (SP4), hosted by Professor Josef Krýsa of the Institute of Chemical Technology Prague was well attended by the Mills Group, with Professor Andrew Mills, two postdoctoral researchers and two PhD students representing the group.
Christopher O’Rourke and Nathan Wells both presented posters during the course of the conference, with the latter also giving a short oral presentation.
Mills group member Katherine Lawrie visited a research group at the University of Cadiz, Spain, as part of a collaboration aimed at creating a colourimetric UV dosimeter for solar water disinfection (SODIS). We want to develop a device which tells users of the SODIS method (typically those in third world countries) when a bottle has been exposed to sufficient amounts of sunshine and the water is safe for drinking.