The mechanical failure of hybrid materials made from polymers and single-wall carbon nanotubes (SWNT) is primarily attributed to poor matrix-SWNT connectivity and severe phase segregation. Both problems can be successfully mitigated when the SWNT composite is made following the protocol of layer-by-layer assembly. This deposition technique prevents phase segregation of the polymer/SWNT binary system, and after subsequent crosslinking, the nanometre-scale uniform composite with SWNT loading as high as 50 wt% can be obtained. The free-standing SWNT/polyelectrolyte membranes delaminated from the substrate were found to be exceptionally strong with a tensile strength approaching that of hard ceramics. Because of the lightweight nature of SWNT composites, the prepared free-standing membranes can serve as components for a variety of long-lifetime devices.

Stable hollow polyelectrolyte capsules were produced by means of the layer-by-layer assembling of poly(allylamine), PAH, and poly-(styrenesulfonate), PSS, on melamine formaldehyde microcores followed by the core decomposition at low pH. These capsules are nonpermeable for urease in water and become permeable in a water/ethanol mixture. The capsules were loaded with urease in water/ethanol mixture and then resuspended in water. The urease molecules are kept in the capsule, whereas the small urea molecules rapidly diffuse through the capsule wall providing a substrate for the biocatalytic reaction.