A common problem of pesticides is that they can be washed away from leaves by rain or from seeds by groundwater which makes the pesticide ineffective and results in higher costs and/or lower crop yields. The efficacy of pesticides can be dramatically increased when applied together with a coating that locks the active ingredients in place. This coating is very similar to paint: it is a waterborne emulsion that can be applied by spraying or simple mixing and forms a thin, coalescent, non-sticky film.
However, the currently used coating materials, which contain polymers—plastics—, are not biodegradable. There are concerns about placing these polymers (as their purpose requires!) directly into the environment. The plastic film, once it physically breaks off a germinated seed, or is left behind by a withered leaf, is expected to fragment into microplastics which ultimately reach waterways and the ocean. This is the same fate of most plastic waste leaked into the environment which has attracted wide-spread attention because of the harmful effects of microplastics on marine life, the food chain, and their suspected role in transferring pathogens. Many governments (including the UK’s) are taking action to reduce microplastics with the current coating technology at risk of facing restrictions. A ban could ultimately result in lower crop yields and a reduced food security in the UK and globally.
While a number of polymers are well-known to be biodegradable, they do not possess the appropriate chemical structure and production route to allow being manipulated into an emulsion with the above paint-like properties. In fact, the paint industry has spent decades of research developing coatings that are as durable as possible and not, by any means, degradable. Very limited literature exists on degradable paint-like coatings.
The University of Surrey has recently developed a novel way to produce biodegradable plastics. Uniquely, this method installs biodegradable linkages into polyacrylates—the material most commonly used in paint—which is not possible with other methods. In this project, we will synthesise new, custom-made materials and will expose them to soil samples, soil microorganisms, and their enzymes in order to quantify, understand, and tune their biodegradation. The project is supported by Syngenta, who will help maximise the project’s real-world impact. Additionally, it is expected that several high-impact publications will arise from this work.
The project is supervised by Dr Peter Roth, an expert in polymer synthesis, and Dr Jose Jimenez, a leading microbiologist experienced in the biodegradation of polymers.
First class or high second class BSc or Master’s level degree (or international equivalent) in chemistry, biochemistry, or a closely related subject area. For non-native English speakers: average score of 6.5 with each individual category at least 6.0 in an Academic IELTS test not older than 2 years.
How to apply:
Please submit your application online: https://www.surrey.ac.uk/postgraduate/chemistry-phd
. Applicants are encouraged to contact Dr Peter Roth first to discuss their application.