Gelation of non-aqueous microgels

Pastes play a critical role in a wide range of industrial technologies and processes. They may be
formed from either (a) a high concentration of expanded microgels particles, or (b) via a
concentrated entangled high molecular weight polymer solution or (c) through a dense, space filling
suspensions of colloidal particles with an added polymer for rheology control. While aqueous pastes
have been studied for many years our understanding of how to produce, control and regulate the
rheology of non-aqueous pastes is by comparison, very limited. A major obstacle to-date has been
(i) a lack of methods to visualise the three-dimensional structure of these highly disordered soft
glassy materials and (ii) a conceptual framework to rationalize and hence predict the relationship
between processing conditions, intermolecular interactions and the constitutive rheological
properties of the paste.
The aim of this project will be to develop a physical understanding of the links between the
microstructure of a non-aqueous paste and its rheological properties. Using fluorescence confocal
microscopy in combination with single particle micro-rheological and bulk rheology measurements
we will quantify the network geometry of a range of competing non-aqueous pastes. These
structural insights will be used to develop conceptual models to predict the rheological properties of
the paste from the underlying microstructure.