Rheology of Colloidal Gels

Lead Research Organisation: University of Oxford
Department Name: Oxford Chemistry


Gelling agents are of interest for both academic and industrial purposes. In fact, in industry they can be used as thickeners preventing sedimentation and allowing a better homogeneity of products that can last for longer without the disadvantage of microbial spoilage, for example. Hence, a huge diversity of gelling agents with different rheological properties exists on the market and are suitable for different systems (water or oil based system) and applications (food or cosmetic). However, it is also possible to tailor their rheological properties by changing interactions between the particles or molecules in a system. It can be achieved by using salt, varying the pH or changing the surface of the particles. Nevertheless, a gelling agent having desired rheological properties can also feature some benefits due to the effect of time on the matrix for instance. Hence, this project can lead to the formulation of gels or the synthesis of modified gelling agent having desired rheological properties. The understanding of these properties will contribute in building a better comprehension of the gel structure and its evolution with time, and could serve as guide to tailor rheological properties of gels. With the support of Syngenta as industrial partner, this project aims at developing alternative gelling agents or formulations to replace the currently used one while complying with rheological requirements. From an academic point of view, the goals of this project are multiple. One is to understand how inorganic gelling compounds behave with time by determining an aging kinetic as well as trying to prevent it. Another goal is to understand why they feature the same rheological properties as polymeric compounds. This project is mainly focused on using mineral compounds as gelling agent. As part of the project, different inorganic materials will be rheologically characterised. These inorganic materials will consist mainly of clays which can be either synthetic or naturals. First of all, clays already available on the market are investigated. The ones having the most promising characteristics will be kept. Then, several options can be conceivable to create a gel having the same rheological properties as the already existing and referenced one. One will be to work on the formulation of the gel, trying to mix different clays or playing with salt and/or pH. Another option will be to modify the selected clays by coating them for example to tailor their rheological properties. This project falls within the EPSRC Physical sciences research area and Prosperity ambition as it contributes in bringing academic purpose and industry relevance together through the high involvement of the Colloid group at the University of Oxford and Syngenta. It will also contribute in developing new systems that could be used in the future by industries to improve manufacturing of products while building a better understanding of them.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S513866/1 01/10/2018 31/03/2024
2217585 Studentship EP/S513866/1 01/10/2018 30/09/2022 Camille Boulet
Description A new formulation based on the blend of two inorganic compounds was developed in order to mimic the rheological properties obtained using the standard polymer (xanthan) -clay combination currently used for product formulation in industry. This combination has been filed for patenting in June 2020. Further work was carried out to better understand this mixture at a microscopic scale for instance its microscopic structure and to figure out or to predict its rheological properties when submitted to different environmental constraints, i.e change of pH, salt or surfactant concentration for instance.
Furthermore, the ageing of another mixture of clays compared to the ageing of each clay on their own, revealed an interesting structure in which the needle-shaped clay "coated" the platelet-shaped clay.
Exploitation Route Regarding the research related to the patent, the University of Oxford owns the patent but a discussion between the University and Syngenta (industry supporting this project) may lead to Syngenta using it for new product development and commercialisation.
Regarding the study of the ageing of clays: The two clays are used in industry in the formulation of final products so that they can meet suitable rheological properties. However, such systems are prone to ageing, which impacts the shelf life of the product. By mixing clays, which seems to age via different mechanisms, we expect to slow down the ageing effect. We will also study the interaction between these clays at a microscopic level.
Sectors Agriculture, Food and Drink,Chemicals,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

Description Our finding can be used in the future for the formulation of products to prevent phase separation like sedimentation from happening. Hence, it allows the active ingredients to stay homogeneously distributed in the gel, whilst the gel can still easily flow. It can be used in different sectors such as in agriculture, paints, cosmetics, pharmaceutics, etc.
First Year Of Impact 2019
Sector Agriculture, Food and Drink,Chemicals
Impact Types Economic

Description Industrial partner - Syngenta 
Organisation Syngenta International AG
Department Syngenta Ltd (Bracknell)
Country United Kingdom 
Sector Private 
PI Contribution We have been able to find a combination of clays, which mimics the rheological behavior of the composition currently used by the company. We have patented the formulation, and expect it to be used in the future by the company in their products.
Collaborator Contribution This project is supported by Syngenta which also gives me access to their research facilities. Hence, I regularly perform some Cryo-SEM there and Ih have taken a one week course on how Syngenta makes and assesses products during the research stage. I have also attended a conference gathering researchers supported by Syngenta throughout the UK during which talks were given by professors and posters were presented by students. Besides, some people within this industry helped me with my project by designing an experimental plan for instance or by giving me ideas on where to focus my research on.
Impact Cryo-SEM pictures of gels were taken to access the micro-structure of the gel. In addition, we are trying to establish a mathematical model using response surface methodology in order to map or predict the rheological behaviour of the gel according to different environmental conditions (for instance the pH, the ionic strength of the gel, temperature and so on). Experiments were already performed and the model seems promising to predict certain responses but further work need to be carried out to improve it.
Start Year 2018
Description The invention relates to a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification. 
IP Reference WO 2021/250383 Al 
Protection Patent application published
Year Protection Granted 2021
Licensed No
Impact Patent has been published in December and hasn't had any impact yet.