A recyclable supramolecular membrane for size-selective separation of nanoparticles

Abstract

Most practical materials are held together by covalent bonds, which are irreversible. Materials based on noncovalent interactions can undergo reversible self-assembly, which offers advantages in terms of fabrication, processing and recyclability, but the majority of noncovalent systems are too fragile to be competitive with covalent materials for practical applications, despite significant attempts to develop robust noncovalent arrays. Here, we report nanostructured supramolecular membranes prepared from fibrous assemblies in water. The membranes are robust due to strong hydrophobic interactions, allowing their application in the size-selective separation of both metal and semiconductor nanoparticles. A thin (12 µm) membrane is used for filtration (∼5 nm cutoff), and a thicker (45 µm) membrane allows for size-selective chromatography in the sub-5 nm domain. Unlike conventional membranes, our supramolecular membranes can be disassembled using organic solvent, cleaned, reassembled and reused multiple times.

Hydrophobic Self‐Assembly Affords Robust Noncovalent Polymer Isomers

“…Hydrophobic interactions appear to be the most suitable to emulate covalent polymerization as they can be sufficiently strong to dramatically influence chemical properties, [4] and create robust functional materials from well-defined amphiphiles. [5] While the hydrophobic assemblies are robust in neat water, the presence of an organic solvent mitigates hydrophobic bonding to render the assemblies dynamic and adaptive. [6] Herein we report on the employment of a single building block to assemble two supramolecular polymer isomers in water, two isomers that have different structures as well as electronic and photophysical properties.…”

Ultra‐Thin Self‐Assembled Protein‐Polymer Membranes: A New Pore Forming Strategy

“…In earlier studies this proved a suitable method to determine selectivity using TEM and spectrophotometry. [ 11,40 ] For this a single stock solution of a mixture of gold nanoparticles in the range of 2-30 nm was used in all experiments. The fi ltration was performed in the same setup as was described before at 40 °C since above the LCST the most signifi cant difference in permeation was observed.…”

Advances in Switchable Supramolecular Nanoassemblies

“…Filtration of a 5 10 À4 m aqueous solution of assembled 16 on a cellulose acetate (CA) filter with a pore size of 0.45 mm produced a approximate 45 mm thick layer of the supramolecular network on top of the CA support ( Figure 35). [47] This network could then be used to size-separate gold nanoparticles from solution by filtration. Cryo-TEM images confirmed that gold nanoparticles bigger than about 5 nm were not able to pass through the membrane and remained on the network.…”