Hybrid GUVs were prepared using the electroformation method from 6.57 mM POPC and PBd-b-PEO solutions in various polymer-to-lipid ratios, with either 2 mol% DiO and 10 mol% PBd22-PEO14 -TMR for FRAP and lipid/polymer mixing ratio experiments, or 0.5 mol% Laurdan for membrane hydration measurements. True mole fractions of POPC, PBd-PEO, DiO and PBd22-PEO14 -TMR in PBd22-PEO14 and PBd12-PEO11 GUV compositions are provided in the ESI.