Abstract: An asymmetric membrane. The asymmetric membrane includes a membrane wall with a first and a second porous surface and an interior situated between the surfaces; a first asymmetrical region towards the first surface; a second asymmetrical region towards the second surface; wherein the asymmetric membrane is made from a polymeric blend comprising an aromatic sulfone polymer and poly (2-oxazoline); and wherein the asymmetric membrane is in the form of a flat sheet.

Abstract: Solutions containing oppositely-charged nanoparticles (NPs) deposit “patchy” coatings of alternating charge distribution on various types of materials, including polymers, elastomers, and semiconductors. Surface adsorption of the NPs is driven by cooperative electrostatic interactions and does not require chemical ligation or layer-by-layer schemes. The composition and the quality of the coatings can be regulated by the types, charges, and the relative concentrations of the NPs used and by the pH. Dense coatings can be formed on flat, curvilinear, or micropatterned surfaces. The coatings are stable against common chemicals for prolonged periods of time, and can be used in applications ranging from bacterial protection to plasmonics.