The project aims to investigate sev-eral fundamental issues of a break-through technology on high-flux loe-fouling water purification filters being developed at Stony Brook. This breakthrough technology is based on a new concept of com-posite membrane design, involving (1) the replacement of convention-al flux-limited porous membrane layer with a high flux non-woven nanofibrous support, containing an asymmetric structure with inter-connected void morphology, and (2) the coating of a very thin barri-er layer of strong and functional polymer nanocomposite on the nanofibrous scaffold. Preliminary experiments on the hierarchical structure of the design and assem-bly of this unique nanofibrous nanocomposite membrane, with or without the mid-layeer support, have already revealed very promis-ing potential (e.g. by using a non-porous hydrophilic nanocomposite coating top-layer, an asymmetric electrospun nanofibrous mid-layer and a conventional non-woven microfibrous support, the flux rate of several such not yet optimized systems, is already 5-10 times more than that of the best among conventional UF media with com-parable rejection ratio and low fouling criteria. (ONR)