Polymer-mediated phase stability of colloids

Abstract

In this thesis, we have isolated some key parameters governing the (in)stability of colloid--polymer mixtures. The term `colloid' refers to a state of matter in which a certain amount of material (with one of its dimensions between {one nanometre to one micrometre}) is dispersed in another medium. Polymers are macromolecules constituted of many repeating units called segments; depending on the number and nature of these segments, polymers may dissolve or phase-separate in solution. Colloid--polymer mixtures are widespread in biological systems (including blood, the cytoplasm of a living cell, and plant sap), as well as in man-made products (such as paints, drinking yogurt, and printing inks). Better control over the stability limits during product development is possible via a fundamental understanding of the effect of some relevant parameters in the system at hand. In the examples given above, multiple colloids, polymers, and other components are often present. Building knowledge on the interactions between components of the same nature, and pairs of different components is a logical starting point. We focus on three kind of colloids (spherical, anistropic, and associative) and study how the phase stability is affected upon addition of polymers.