The peak-to-peak measurements from SAXS, cryo-ET, FFT and SPA profiles of 100 mol% PBd22PEO14 and thick 50 mol% PBd22PEO14 membranes can be compared with the theoretical values obtained from a polymer random walk model. The peak-to-peak values from all techniques are all below the predicted hydrophobic thickness for fully segregated polymer leaflets, but above the thickness calculated from fully interdigitated membranes (55 Å), suggesting PBd22-PEO14 forms only partially interdigitating membranes.