Polymer stabilized lipid nanodiscs offer enormous potential as tools for enabling membrane protein structural studies & biophysics. Previously we studied discs formed using a poly(styrene-alt-maleic acid) (PSMA) copolymer, and also with a commercial poly(styrene-alt-maleimide). However these polymers can be used only over limited pH ranges, as they precipitate when their charge is neutralised. To overcome this we have devised a simple modification of the hydrolysis procedure which produces a zwitterionic version of the copolymer from the same initial poly(styrene-alt-maleic anhydride). The modification can be done to either the widely used commercial polymers, or our controlled Mw copolymers from RAFT polymerisations. Here we wish to measure particles formed using zwitterionic copolymers with DMPC to confirm that they are nanodiscs and to compare to those formed using the acid copolymers