Self-assembly of planar supported lipid bilayers on top of hydrophilic polymer brushes is a desirable alternative to solid supported lipid bilayers and covalently tethered lipid bilayers for applications like sensing on transmembrane proteins which require a large aqueous volume between membrane and substrate. We present a simple dip-and-rinse method to produce poly(ethylene glycol) (PEG) brushes with sparse positively charged hydrophobic tethers, using poly(l-lysine)-graft-poly(ethylene glycol)-quaternary ammonium compound copolymers. The interaction of such polymer coatings with liposomes of different compositions and the conditions for formation of planar lipid bilayers of extraordinarily high fluidity on top of the >10 nm thick reservoir by liposome self-assembly and sequentially triggered rupture are investigated.