Structural, Viscoelastic, and Electrochemical Characteristics of Self-Assembled Amphiphilic Comblike Copolymers in Aqueous Solutions

Abstract

Self-assembly in aqueous solutions of an amphiphilic comblike polyelectrolyte (80C12) that consists of a polystyrene (PS) backbone onto which quaternary ammonium pendant moieties have been grafted has been investigated by light scattering and cryo-transmission electron microscopy measurements in the presence of KCl and methylviologen dication (MV) under conditions mimicking those for electrochemical measurements. Polymer chains self-assemble within branched cylindrical micelles that display viscoelastic properties, characterized by a relaxation time of 4 s. To tune this time, 80C12 was mixed with a polyoxyethylene nonionic surfactant (Brij CE). Relatively increasing the amount of the latter leads to a decrease in the relaxation time of the 80C12 solution. Correlatively, electrochemical experiments with a rotating disk electrode show a transition of the mass transport rate, which deviates from the classical Newtonian behavior in the same velocity domain. This result generalizes what has been already observed with solutions of linear polymers of high molecular weight and wormlike micelles based on surfactants subjected to elongational deformations. Moreover, the critical times derived from rheological and electrochemical experiments display the same trend.

Effect of the Janus Amphiphilic Wall on the Viscosity Behavior of Aqueous Surfactant Solutions

“…For instance, it is known that small amounts of the surfactant (or polymer) can reduce the friction losses in turbulent flows (the so-called “Toms effect” − however, the detailed mechanism has not yet been completely understood.…”

Reversible 2D Supramolecular Organic Frameworks encompassing Viologen Cation Radicals and CB[8]

“…Rational design and synthesis allows the preparation of variety of supramolecular polymers 4 – 8 , cross-linked gel materials 9 , 10 , hierarchical assemblies 11 and metastable polymeric nanoparticles. In the last two decades, several supramolecular structures were designed by chemists using the concept of self-assembly 12 , templating and self-sorting strategies 13 , 14 . Complex-supramolecular architectures between electron deficient and electron rich moieties through non-covalent interactions were developed and were subjected to encapsulation upon addition of respective macrocyclic hosts such as crown ethers, cyclodextrins 15 , 16 , calixarenes 17 , cucurbiturils 18 and pillararenes 19 .…”