Effect of gold nanoparticles on chemical oscillators: A comparative study of the experimental and simulated results

Non-autonomous zinc-methylimidazole oscillator and the formation of layered precipitation structures in a hydrogel

Oscillations are one of the intrinsic features of many animate and inanimate systems. The oscillations manifest in the temporal periodic change of one or several physical quantities describing the systems. In chemistry and biology, this physical quantity is the concentration of the chemical species. In most chemical oscillatory systems operating in batch or open reactors, the oscillations persist because of the sophisticated chemical reaction networks incorporating autocatalysis and negative feedback. However, similar oscillations can be generated by periodically changing the environment providing non-autonomous oscillatory systems. Here we present a new strategy for designing a non-autonomous chemical oscillatory system for the zinc-methylimidazole. The oscillations manifested in the periodic change of the turbidity utilizing the precipitation reaction between the zinc ions and 2-methylimidazole (2-met) followed by a partial dissolution of the formed precipitate due to a synergetic effect governed by the ratio of the 2-met in the system. Extending our idea spatiotemporally, we also show that these precipitation and dissolution phenomena can be utilized to create layered precipitation structures in a solid agarose hydrogel.

0D–2D heterostructures as nanocatalysts for self-oscillating reactions: an investigation into chemical kinetics

Ceria-decorated graphene nanocomposites as an efficient catalyst for the oscillatory Belousov–Zhabotinsky reaction.

Oscillations of pH in the urea–urease system in a membrane reactor

Urea–urease reaction in an open reservoir–membrane–reactor system displays regular spontaneous oscillations of pH.

Tuning the oscillatory dynamics of the Belousov–Zhabotinsky reaction using ruthenium nanoparticle decorated graphene

Ruthenium nanoparticle decorated graphene nano-mats to enhance chemical oscillations in BZ reactions.

The fabrication of a supra-amphiphile for dissipative self-assembly

Dissipative self-assembly is a challenging but attractive field of supramolecular science, because it generally concerns complex systems but is more close to the self-assembly of living bodies. In this article, we realized dissipative self-assembly by coupling a supra-amphiphile with a chemical oscillator. The supra-amphiphile was fabricated with iodine and a double hydrophilic block copolymer containing PEG segments, as the non-covalent interaction between PEG and iodine could turn PEG hydrophobic, leading to the formation of the supra-amphiphile. The self-assembly and disassembly of the supra-amphiphile could be controlled by varying the concentration of iodine. Therefore, the dissipative self-assembly of the supra-amphiphile was realized when it was coupled with the IO3--NH3OH+-OH- chemical oscillator, which was able to produce iodine periodically. Meanwhile, the kinetic data of the self-assembly and disassembly of the supra-amphiphile could be estimated by the theoretical simulation of the chemical oscillations. This line of research promotes the self-assembly of supra-amphiphiles one step forward from thermodynamic statics to a dissipative system, and also suggests a new strategy to investigate the kinetics of stimuli-responsive molecular self-assembly.

Self-Assembly of Charged Nanoparticles by an Autocatalytic Reaction Front

In this work we present that aggregation of charged and pH sensitive nanoparticles can be spatiotemporally controlled by an autonomous way using the chlorite-tetrathionate autocatalytic front, where the front regulates the electrostatic interaction between nanoparticles due to protonation of the capping (carboxylate-terminated) ligand. We found that the aggregation and sedimentation of nanoparticles in liquid phase with the effect of reversible binding of the autocatalyst (H(+)) play important roles in changing the front stability (mixing length) and the velocity of the front in both cases when the fronts propagate upward and downward. Calculation of interparticle interactions (electrostatic and van der Waals) with the measurement of front velocity revealed that the aggregation process occurs fast (within a few seconds) at the front position.

Solvent-starved conditions in confinement cause chemical oscillations excited by passage of a cathodic delamination front

In situand operando Raman spectroscopy shows oscillations in pH during delamination of a polymer coating.