Coupling electrostatic and polymeric surface interactions in soft matter and biology

The behaviour of soft matter and biological systems crucially depends on the forces between the surfaces of their constituents. In recent years, driven by mounting interest in biology, biomimetics and environmental concerns, water based systems are becoming commonplace in experiment. A typical system will comprise water soluble colloids, surfactants, polymers. In water, any ionisable groups will become dissociated, so that theoretical treatments need to account for electrostatic interactions or justify their neglect. As is known to any (perhaps reluctant) student of electromagnetism, neutral, but polarisable!, dielectrics can be strongly affected in the presence of charge. Only recently has the theoretical treatment of soft matter and biology begun to address this, with few unheeded historical exceptions. Within this context, using a simple mean field model, my PhD explored how the interactions between charged surfaces are modified when they interact across an electrolytic solution of dielectric polymers, considering these must electrostatically couple to the surfaces. I will discuss the application of the model to predict the phase behaviour of polymer doped smectics and discuss when it is reasonable to neglect electrostatic interactions in soft matter and biology.