Ulf Olsson

The phase behavior of some different colloid systems is reviewed. Starting off with polymer solutions, we recall that while the monomers are soluble in the solvent, the polymer may not. Two polymers are even less miscible. Block copolymer melts, formed by two immiscible blocks, undergo “microphase separation” and form ordered liquid crystalline phases. Colloidal spheres crystallize at higher concentrations depending on the interactions. Similarly, rod-like and disk-like colloids form nematic liquid crystalline phases. Surfactant systems represent very important systems of association or self-assembly colloids. Here, similar to the block copolymer systems, the phase behavior is particularly rich because of the many ways that space can be divided into separate hydrophobic and hydrophilic domains. Microemulsions are thermodynamically stable liquid phases that can contain simultaneously large amounts of both water and oil. Microemulsions and lamellar phases can be described in terms of flexible surfaces. Here, the monolayer spontaneous curvature plays an important role in dictating the phase behavior and the structure of the microemulsion.