Changes in membrane hydration with increasing polymer fraction in PBd22-PEO14 /POPC and PBd12-PEO11 /POPC vesicle compositions was monitored using the fluorescent probe Laurdan. Previous studies have used the shift in Laurdan fluorescence emission between 444 nm and 488 nm to calculate a General Polarisation (GP) value that can be a quantitative measure for lipid packing. These studies have shown that lipids in the fluid phase are more hydrated, while lipids in the gel phase have more restricted motion, and are less hydrated. GP values close to 1 indicate a highly ordered environment with little to no while a GP towards -1 indicates Laurdan is a well hydrated, disordered environment.