Development and Validation of a Numerical model for Structured Liquids using Formulation Science and Rheology: towards Net Zero Sustainable Products.

The Unilever Group is an international manufacturer of home, personal care and food products, with a purpose to Make Sustainable Living Commonplace. The company has over 400 brands that are sold in over 190 countries, generating an annual turnover of €60bn in 2022. Products containing complex structured liquids are a critical component of this product portfolio e.g. shampoos and hair conditioners (Dove, LUX, Sunsilk). To meet UK climate targets, novel scientific approaches are urgently needed to enable rapid reformulation of both product and process to reduce greenhouse gas (GHG) emissions and water during manufacture and in use. Unilever has pledged to achieve net-zero emissions from all its products from sourcing to point of sale by 2039. The achievement of such a rate of innovation is required due to the increasing shift to ingredients that are derived from sustainable feedstocks, as well as a reduction in the carbon footprint required to manufacture such ingredients.

This PhD project contributes to this goal by testing and development of a novel numerical framework which will enable in silico experiments to be performed to test out new formulations and their microstructures validated against experiments, with the ultimate aim of reduction of time and waste in bringing new formulations to market. The initial focus will be on concentrated products containing Lamellar Gel Networks (LGN). Composed of surfactants and long chain fatty alcohols, the structural features of LGNs are built over three orders of magnitude, from self-assembled repeat-unit bilayer structures at the nanometre-scale, to stacking of these into intermediate mesostructures to form higher order sheet-like agglomerates with dimensions in the order of tens to hundreds of micrometres, which twist, fold and interlock with other sheets. These structures build viscosity and contribute to the overall feel and flow of the product which is pleasing to the consumer.

This project aims to validate and further develop a preliminary model of microstructures using meshless numerical methods, via a combination of simulations (in silico) and laboratory (in vitro) experiments. The candidate will familiarise themselves with these and will propose low complexity experiments in both formulations and simulations to create capability to predict rheological properties of complex liquids, with an emphasis on lamellar gel networks.

The student will benefit from interactions with the Unilever team at Port Sunlight on the S&T Conditioner Programme and will practice project management within their PhD project and present their work by means of regular team and wider community updates. The student will be aligned with the CDT in Formulation Engineering and gain access to all cohort activities including research skills, soft skills and business modules offered include innovation and entrepreneurship as well as presentation practice at the CDT Spring Conference held annually.

Funding notes:

Tax free stipend of £19,795 and £5,000 industrial top up per annum plus fees paid.

To be eligible for EPSRC funding candidates must have at least a 2(1) in an Engineering or Scientific discipline or a 2(2) plus MSc.