Nanostructured lipid aggregates offer enormous potential as tools for membrane structural biology and biophysics. Poly(Styrene-Maleic Acid) stabilized lipid nanodiscs have a number of attractive characteristics including stability, ease of preparation and cost, but questions remain over the mechanism by which the polymer interacts with the lipids to stabilize the nanodiscs. So far our experiments have used a polydisperse commercial polymer. We have now synthesised polymers with well-defined molecular weights using RAFT polymerisation, and also analogues with the styrene component deuterated providing a new set of contrasts in this polymer-lipid system. Here we propose to investigate the effect of polymer molecular weight on the nanodisc size and shape for several lipid compositions, and also, using contrast, to highlight the location and role of the polymer in stabilizing the nanodiscs.