Soft matter is an important class of materials that typically consists of colloidal particles and/or polymers in a liquid medium. For certain compositions, these types of systems tend to (micro-)phase separate and unmix into coexisting phases that differ in composition, structure, and properties. Ph.D.-researcher Joeri Opdam developed theoretical methods to accurately predict the phase behavior of soft matter systems that consist of colloidal mixtures and block copolymers, which is crucial for their applications in products as coatings, pharmaceuticals and food.