Chemically coded time-programmed self-assembly

Abstract

Coupling of a pH clock reaction (activation) with lactone hydrolysis (deactivation) can control and drive the self-assembly of pH-responsive building blocks.

Clocking the Clock: Programmable Acid Autocatalysis in the Chlorite‐Tetrathionate Reaction

“…This behavior is often due to autocatalysis, a positive feedback mechanism in which a reaction product catalyzes its own formation . Clock reactions are versatile tools for programming the assembly and/or disassembly of pH‐responsive building blocks, as well as for controlling polymerization and sol‐gel transition in the time domain.…”

Transient supramolecular assembly of a functional perylene diimide controlled by a programmable pH cycle

“…Notably, the overall pH evolution was not affected by the presence of the PDIamine building block, demonstrating that it is possible to obtain macroscopic selfassembly without impacting on the molecular control network. 29 Eventually, as showed in Fig. 4D, periodic cycles of assembly and disassembly were obtained under semi-batch conditions by restoring the pH to alkaline with controlled additions of NaOH.…”

“…28 Among lactones, d-gluconolactone (GL) has risen to the forefront thanks to its non-toxicity, water solubility, availability, and the relatively low pK a (3.86) of its hydrolysis product, gluconic acid. This approach was recently applied 29 to control the reversible assembly and disassembly of micelles and colloids, as well as the swelling/shrinking of a pH-responsive hydrogel. However, so far only one short-lived pH pulse has been demonstrated, due to the fast hydrolysis of GL ( Fig.…”

Two‐Stage Polyelectrolyte Assembly Orchestrated by a Clock Reaction

“…Clock reactions, molecular reaction networks characterized by an abrupt increase in the product(s) concentration after a well-defined lag time, [13] are promising alternatives for the programming of pH changes. [14][15][16][17] Clock reactions have been applied to temporally modify the viscosity of polyelectrolyte solutions, [18] to regulate the (dis)assembly of micelles and polymeric networks [19] , to control the rate of polymerization [20] or the formation of nanoparticles [21] and supramolecular assemblies [22,23] in time. In this regard, the formaldehyde-sulfite (FÀ S) clock reaction is of special interest.…”