The focus of the talk is on the preparation and study of surface modified synthetic opals. Synthetic opals form via self-assembly of sub-micron-sized silica spheres into a close-packed face-centered cubic (fcc) lattice. The opals contain highly ordered arrays of three-dimensional interconnected pores 10-100 nm in size. Synthetic opals are: • formed through self-assembly • allow easy control of nanopore size in a broad range • possess exceptionally high molecular throughput • offer a large variety of surface chemistries • allow creating multilayer membranes with orthogonal permselectivity

By chemically modifying the nanopore surface with organic molecules we are able to create membranes with selective permeation of one species compared to other diffusing species in a mixture, and with exceptionally fast environmental response. The transport through the opals is controlled in the following three modes: • Electrostatic (by charging the pore surface via protonation, irradiation with light, or metal ion binding). • Affinity (by non-covalent interactions with molecules attached to the pore surface). • Steric (by changing conformation of organic polymers inside the pore in response to external stimuli, e. g. solvent, temperature, light, or binding).

The talk will describe our recent results in controlling transport of molecules through opals, as well as preparation of suspended opal membranes.