Integration of molecular machines into supramolecular materials: actuation between equilibrium polymers and crystal-like gels. Issue 46 (21st November 2017)

• Record Type: Journal Article
• Authors: Mariani, Giacomo; Goujon, Antoine; Moulin, Emilie; Rawiso, Michel; Giuseppone, Nicolas; Buhler, Eric
• Is Part Of: Nanoscale. Volume 9:Issue 46(2017)
• Page Start: 18456
• Page End: 18466
• Publication Date: 2017-11-21
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c7nr04251e
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : A phase transition between equilibrium polymer solutions and crystal-like gels can be controlled by the pH nano-actuation of the mechanical bond of a rotaxane-based supramolecular polymer. Abstract : In this article, the dynamic structure of complex supramolecular polymers composed of bistable [ c 2]daisy chain rotaxanes as molecular machines that are linked by ureidopyrimidinones (Upy) as recognition moieties was studied. pH actuation of the integrated mechanically active rotaxanes controls the contraction/extension of the polymer chains as well as their physical reticulation. Small-angle neutron and X-ray scattering were used to study in-depth the nanostructure of the contracted and extended polymer aggregates in toluene solution. The supramolecular polymers comprising contracted nanomachines were found to be equilibrium polymers with a mass that is concentration dependent in dilute and semidilute regimes. Surprisingly, the extended polymers form a gel network with a crystal-like internal structure that is independent of concentration and reminiscent of a pearl-necklace network.