Can interfacial relaxation encode three-dimensional membrane remodelling?

Biological membranes are dynamic soft interfaces in which molecular interactions govern their structure and organization across multiple length and time scales. Processes such as structural remodelling, fusion and curvature generation arise from collective molecular rearrangements within these highly complex environments. Despite the widespread use of simplified membrane models, establishing meaningful links between (two-dimensional) interfacial systems and three-dimensional membrane behaviour remains a major challenge. In this perspective, we discuss how studies on Langmuir monolayers may provide access not only to equilibrium membrane thermodynamics, but also to the relaxation phenomena underlying membrane transformations. Focusing on interfacial rheology, with particular attention to mechanical hysteresis, we discuss how dynamic interfacial observables may provide experimentally accessible indicators of how lipid assemblies accumulate, dissipate, and reorganize lateral stresses, and how such responses may become linked to membrane organization and remodelling. Beyond their role as simplified membrane mimics, we discuss recent literature on Langmuir monolayers, and we explore the possibility that dilatational and shear relaxation modes measured in monolayers (2D relaxation) contain information relevant to membrane self-assembly (3D remodelling).