Covalent Partners, LLC (Hayward, CA) inventors Joshua W. Kriesel, Donald B. Bivin, David J. Olson and Jeremy J. Harris developed a catalog of nanofilms with polymeric components that can be made impermeable to viruses and larger biological species. The films are used to make selectively permeable membrane barriers for the separation or filtration of materials from fluids, according to United States Patent 7,595,368. The 134 page patent divulges a variety of nanofilms for material separation.
Conventional membranes used in a variety of separation processes can be made selectively permeable to various molecular species. The permeation properties of conventional membranes generally depend on the pathways of transport of species through the membrane structure. For example, while the diffusion pathway in conventional selectively permeable materials can be made tortuous in order to control permeation, porosity is not well defined or controlled by conventional methods. The ability to fabricate regular or unique pore structures of membranes is a long-standing goal of separation technology. Covalent’s discoveries are a step closer to that goal.
Selective filtration and relative clearance of solutes is exemplified in the Table Clearance of Solutes by Nanofilms, where the heading "high permeability" indicates a clearance of greater than about 70-90% of the solute. The heading "medium permeability" indicates a clearance of less than about 50-70% of the solute. The heading "low permeability" indicates a clearance of less than about 10-30% of the solute.
Nanoflims for filtration were prepared from amphiphilic species and one or more polymeric components. The amphiphilic species or components may be oriented on an interface or surface. Nanofilms may be prepared by coupling one or more of the components. The nanofilms may also be deposited or attached to a substrates.