Deep eutectic solvents are liquids composed of two compounds with a significant melting point depression. Most popular are mixtures of choline chloride, a provitamin produced on the megaton scale. Deep eutectic solvents composed of polymerizable compounds allow frontal polymerization at low temperature and with full conversion and thus, unique functional coatings can be obtained. To understand the origin of non-ideal mixing behavior of deep eutectic solvents, we have investigated a homologous series of choline chloride by molecular dynamics simulations. We found that the incorporation of the anion into the hydrogen bond network plays a central role for the observed properties. Additionally, we will present a polarizable force field developed to study the ion correlation in these liquids.