Influence of Polymer Architecture on the Electrochemical Deposition of Polyelectrolytes

Abstract

This study demonstrates the effect of polymer topology and molar mass on the electrodeposition of preformed polyelectrolytes. The polyelectrolyte solubility is manipulated electrochemically using a counterion switching approach. Upon this, a triggered film formation occurs upon oxidation of hexacyanoferrate(II). The resulting Pt-electrode deposit consists of polycationic chains, namely poly{[2-(methacryloyloxy)ethyl]trimethylammonium chloride} (PMOTAC), which are physically crosslinked by polymer-complexing ferricyanides. Within this study the architecture of the polyelectrolyte is varied from monomeric units over linear and star-shaped polymers to network-like microgel colloids. Film deposition is observed only for linear and star-shaped polymers being pronounced for shorter linear chains at equimolar charge ratios. Quantification is achieved by help of the deposition efficiency DE obtained by analyzing the currents of a rotating ring disk electrode (RRDE) during hydrodynamic voltammetry. DE relates the amount of deposited ferricyanides to the total amount of electrochemically-produced ferricyanides. DE is used to estimate the deposited mass and film thickness showing good agreement with the film thickness determined experimentally by Scanning Force Microscopy. For future applications these results might help optimizing beneficial film formation or minimizing detrimental film formation during other procedures.

Cargo shuttling by electrochemical switching of core–shell microgels obtained by a facile one-shot polymerization

“…Less common is the use of polymeric nanoparticles 20. Though redox-active polymers have been known for decades, utilization of an electrochemical stimulus21–23 to switch polymer properties is a rather undiscovered field compared to the vast majority of reports dealing with stimuli such as temperature, light and pH to induce changes in the polymer chain conformation 13,24. This particularly holds for microgels,25 which are crosslinked polymeric particles in the colloidal size range, often with an ability to undergo a volume phase transition (VPT) upon response to the environmental changes 9,11,26.…”

Influence of Polycation Composition on Electrochemical Film Formation

“…Another way of introducing electrochemical stimulation in those systems is the complex formation of polyelectrolytes with electroactive counterions [ 26 , 27 ]. As in previous works, we use this modular approach to perform a counterion valency-induced deposition (CVID) of cationic polyelectrolytes interacting with hexacyanoferrate ions [ 28 ]. Film formation and film dissolution triggered by a valency change of the hexacyanoferrate redox couple has already been known since the 1980s.…”

“…In a previous study, we investigated different architectures of the cationic poly{[2-(methacryloyloxy)ethyl]trimethylammonium chloride} (PMOTAC) and their influence on electrodeposition using the CVID approach [ 28 ]. The architecture was varied between monomer units, linear and star-shaped polymers, and crosslinked polymer particles (microgels).…”

Photoresponsive Conjugated Microporous Polymer Films Fabricated by Electrochemical Deposition for Controlled Release

“…CMP is becoming an important functional material because of its unique advantages of high specific surface area and π‐conjugated skeleton . ED approach is an electrochemical way to fabricate crosslinking polymer films from small molecule or polymeric precursors, which combines polymerization in solution and in situ deposition on the destination electrodes in one step . ED films have been proved to be potential materials used in organic light‐emitting diodes (OLED) devices, and patterned surface morphology devices, because of their characteristics of high crosslinking density, good stability, and well‐controlled structure.…”