Novel microcapsule designs and manufacturing processes

This project aims to tackle major industrial challenges, which limit the full uptake of microencapsulation technology in a broad range of areas including paints and coatings, home and personal care, agrochemicals and lubricants to name but a few.
Ideal microcapsules are typically core-shell structures, of sizes in the range of micrometres, capable of retaining valuable active ingredients such as pharmaceutical drugs or fragrance oils within their core and releasing them in a controlled manner at a location and rate that is predetermined. In order to design efficient microcapsule systems, it is critical that the properties of both microcapsule core and their protective shell are well controlled and fully optimised for their specific application. This includes for example delivery of enzymes in washing powders, of pesticides for agro-chemicals, of flavours in foods, of biocides in paints/coatings and of antioxidants in cosmetics.
Currently, most commercial microcapsules are spherical structures with a shell made from synthetic or bio-sourced polymers. These designs suffer from significant drawbacks, including: a) microcapsule shell porosity is often too high and does not allow for efficient retention of the active ingredients before the intended delivery - this is a significant challenge in medical applications to minimise the side effects from leaching drugs; b) microcapsule deposition and retention on the targeted surface is often too low - this leads to a very large proportion of microcapsules containing perfume oils being washed down the drain in a washing machine cycle, thus potentially causing both water contamination and higher doses needed (i.e. increased product cost); c) polymer shells are often made from synthetic non-recyclable and non-biodegradable materials, which cause environmental pollution when they unintentionally accumulate, a major current environmental safety concern currently being increasing regulated; and d) microcapsules are mostly manufactured from precursor objects in the form of emulsion droplets, which are typically produced using very energy-intensive and wasteful processes.

Addressing the important challenges above is key if the large potential of microencapsulation technology is to be harnessed a) for more targeted and more efficient delivery (including the use of much lower dosages and the drastic reduction in side effects) of pesticides in agricultural fields, potent drugs in treating serious diseases for example and b) for developing new solutions in a wide variety of industries, for example via designing new energy storage devices for more efficient home insulation.

On this basis, our project will combine the strength of three of the most active UK academic groups and strongly committed key industrial partners to develop solutions to these challenges, including:
- Developing a low energy manufacturing process to produce the emulsion droplet precursors to microcapsules;
- Designing and testing a range of alternative microcapsule shell inorganic chemistries (i.e. not organic polymers) that improve properties of current systems, including:
- More robust and less permeable shells to decrease shell permeability and thus also reduce potential for undesired leaching (and side effects) of the encapsulated active ingredients;
- More sustainable and biodegradable shells that do not linger in the locations they accumulate;
Producing microcapsules of non-spherical shapes to improve their deposition and retention on the targeted surfaces (through increased surface area of interaction with the surfaces), thus enabling more efficient use and lower dosages of active ingredients to be achieved.

The project will fund 3 post-doctoral researchers working on the various aspects discussed above via EPSRC and a combination of the academic institutions and the industrial partners will provide additional funding for 2 PhD students also working on parts of the overall project.