Liquid-liquid immiscibility in spinodal systems exhibits a rich variety of domain morphologies and shape transitions.  A generic description for domain formation invokes competing interactions; van der Waals attraction and long-range dipolar repulsion. In equilibrated Langmuir films, such a description predicts a variety of ordered shapes, the most common being stripes and bubbles.[1] In practice however disordered stripes are most frequently observed.  These have been most extensively documented for interfacial Langmuir monolayers of phospholipids and cholesterol examples such as 65% DMPC: 35% Cholesterol.[2],[3]^,[4]  Despite vast experimental effort in equilibrated phospholipid monolayers, reports on the observations of ordered morphologies (and transitions among them) are rare.  Herein, we report the observation of homogeneous-bubble-stripe morphology during relaxation of pre-compressed langmuir monolayers of Poly(oxyethylene) (PEG)-amphiphile and a phospholipid at vanishing pressures. The PEG-amphiphiles used are single-chain polymers terminated with an alkyl tail.  The bubble to stripe transition in these PEG/phospholipid systems only occurs at a specific percent concentration of the mixtures.  The domain evolution is area and time dependent as well (figure 1).