Professor Colby’s research group is interested in a molecular-level understanding of dynamics in interesting liquids. Polymer liquids are good examples because they are viscoelastic: While polymer liquids do flow, they have considerable elastic character. Other examples include many “complex fluids” such as liquid crystals and surfactants. The Colby group measures the dynamics of these liquids using mechanical rheology and dielectric spectroscopy and also characterizes the liquid structure using neutron and x-ray scattering and optical methods. This is classical materials science research on structure-property relations but at the same time is highly innovative because it is applied to the liquid state! One nice example is the study of ion transport in ionomer membranes. Ionomers are polymers with one type of ion covalently bonded to the chain and are ‘single-ion conductors’ in that only the unattached counterions can move rapidly in response to an applied electric field. Designing ionomers for facile ion transport is challenging and the Colby group is attacking this problem with ab initio calculations of ion interactions that guides our synthesis of new ionomers. We use small-angle X-ray scattering (picture above), mechanical rheology and dielectric spectroscopy to understand what the ions are doing in these new ionomers. We quantify the temperature dependences of the fraction of ions in ion pairs, conducting triple ions and quadrupoles, for different ionomers with various counterions (figure below). There are a great many interesting liquids known in the world today and more are being discovered every day. The Colby group’s mission is to understand in detail the structure-property relations of all interesting liquids. This is a great challenge and as such, only the best highly motivated students are able to participate in this exciting mission.