A long term goal for biophysical studies has been to fabricate bio-membranes on solid supports. A highly hydrated ¿cushion¿ between the membrane and the underlying support can be used to allow the study of membranes under more biologically relevant conditions. Due to its biocompatibility, polyethylene glycol (PEG) has become a commonly used platform for cushioning membranes. A phase diagram for PEG lipopolymer membrane cushions show that these systems are potentially highly tunable and can yield qualitatively different architectures. For the proposed experiments, polarized NR and magnetic contrast variation will be used to characterize PEG lipopolymer membrane architectures and identify the region in phase space in which they reside. Membranes incorporating lipopolymer will be manipulated into different regions within the phase diagram by changing the surface potential of the support.