The main research question is to research and develop a method for measuring in line viscosity of non-Newtonian complex fluids with particular applications to personal care products such as hair shampoos and conditioners. The objective is to develop and test a appropriate methods in the lab in static samples and then build up to demonstrating it in Unilever's pilot plant facility and/or manufacturing plants. The motivation for addressing this problem is that currently samples being processed have to be extracted and taken to a nearby laboratory for manual measurement of viscosity. With the returned result, changes or further processing may need to be made to the produced product and the overall process. If an in-line sensors could be developed then there is the scope for significant wastage reduction, energy reduction and time spent in processing leading to increased efficiency. A smart sensor would also contribute to the overall process control of the system.

The approach being investigated is to explore non-invasive optical spectroscopic techniques such as mid-infrared and near-infrared spectroscopy and Raman spectroscopy. Suitable probe designs will also need to be investigated. The data will require advanced multivariate data analytical techniques to correlate any changes in the spectra with viscosity. Studies of different feedstocks and different process regimes such as flow rates will be considered in addition to the influence of temperature which strongly influences viscosity. The complication is that the types fluids under consideration are complex and behave in a non-Newtonian manner.

Fundamental understanding of the physical origin of any correlations will be explored in terms of changes to the microstructure of the materials and how this influences viscosity.

The research fits into the EPSRC Future Manufacturing and digital manufacturing themes.