Biological membranes are a dynamic platform essential to many biological functions; however, it is still not clear how the bilayer structure, dynamics and functionalities are correlated.   Our understanding is in part limited by experimental challenges in accessing the necessary length and time scales to probe the dynamics that span several orders of magnitude in these complicated systems.   We are interested in understanding the structures, molecular motions and collective membrane dynamics in these self assembled systems as a function of lipid composition as well as inclusions such as cholesterol and proteins and how those might be affected by external stimuli from charge screening to pressure. In particular we are interested in correlating the membrane mechanical properties with their dynamical responses and functional activity. Our primary tools are neutrons spectroscopy and scattering which allows us to measure the time scales and length scales of interest with the unique ability to selectively probe a portion of the assembly by isotopic labelling.