Ultrathin freestanding nanoporous membranes prepared from polystyrene nanoparticles

Freestanding cross-linked polystyrene nanoparticle membranes with a thickness of 80 nm and precisely controlled pores were prepared by filtering polystyrene nanoparticles on a microfiltration membrane by using a sacrificial layer of metal hydroxide nanostrands. The membranes could quickly separate small proteins and gold nanoparticles, showing surprisingly sharp cut-off properties.