Reversible attachment of nanostructures at molecular printboards through supramolecular glue

Regenerable surfaces and reversible attachment of nanostructures onto them is an important aim in nanotechnology. Reversible attachment of nanostructures at molecular printboards was illustrated by the adsorption and desorption of beta-cyclodextrin (beta-CD)-functionalized nanoparticles onto and from stimuli-responsive preadsorbed ferrocenyl-functionalized poly(propylene imine) dendrimers at a beta-CD self-assembled monolayer (SAM). Electrochemical oxidation of the ferrocenyl endgroups was employed to induce desorption of nanostructures from the beta-CD SAMs. A combined surface plasmon resonance spectroscopy and electrochemistry setup was used to monitor the in situ adsorption and desorption of ferrocenyl dendrimers and beta-CD-functionalized Au nanoparticles (CD-Au, d similar to 2.8 nm) onto and from the molecular printboard. In the case of the larger beta-CD-functionalized silica nanoparticles (CD-SiO2, d similar to 60 nm), ultrasonication was used to reduce the desorption time. By electrochemical oxidation applied to a specific area of a nanoparticle layer, local desorption of nanoparticles was observed. In the nonoxidized area, nanoparticles remained robustly attached to the surface; whereas nanoparticles on the electrochemically oxidized area were completely removed.