Nonlinear Kinetic Behavior in Constitutional Dynamic Reaction Networks

Creating synthetic chemical systems which emulate the complexity observed in cells relies on exploiting chemical networks exhibiting nonlinear kinetic behavior. While control over reaction complexity using synthetic gene regulatory networks and DNA nanotechnology has developed greatly, little control exists over small molecule reaction networks. Toward this goal, we demonstrate a general framework for inducing nonlinear kinetic behavior in dynamic chemical networks based on molecules containing reversible chemical bonds. Specifically, this strategy relies on constituent species with differing thermodynamic stabilities that readily exchange components at rates that are faster than their formation rates. Such nonlinear networks (NLN) readily lead to sigmoidal kinetic profiles as a function of the relative thermodynamic stabilities of the constituent species. Furthermore, this behavior could be readily extended to more complex mixtures while maintaining nonlinearity. The generality of this method opens the possibility to generate nonlinear networks using a broad range of small molecule structures

Anisotropic Self-Assembly of Supramolecular Polymers and Plasmonic Nanoparticles at the Liquid–Liquid Interface

The study of supramolecular polymers in the bulk, in diluted solution, and at the solid–liquid interface has recently become a major topic of interest, going from fundamental aspects to applications in materials science. However, examples of supramolecular polymers at the liquid–liquid interface are mostly unexplored. Here, we describe the supramolecular polymerization of triarylamine molecules and their light-triggered organization at a chloroform–water interface. The resulting interfacial nematic layer of these 1D supramolecular polymers is further used as a template for the precise alignment of spherical gold nanoparticles coming from the water phase. These hybrid thin films are spontaneously formed in a single process, without chemical prefunctionalization of the metallic nanoparticles, and their ordering is improved by centrifugation. The resulting polymer chains and strings of nanoparticles can be co-aligned with high anisotropy over very large distances. By using a combination of experimental and theoretical investigations, we decipher the full sequence of this oriented self-assembly process. In such a highly anisotropic configuration, electron energy loss spectroscopy reveals that the self-assembled nanoparticles behave as plasmonic waveguides