Formation of redox-active self-assembled polyelectrolyte–surfactant complexes integrating glucose oxidase on electrodes: Influence of the self-assembly solvent on the signal generation

Mass and charge transport in highly mesostructured polyelectrolyte/electroactive-surfactant multilayer films

HYPOTHESIS

Dimensionally stable electroactive films displaying spatially addressed redox sites is still a challenging goal due to gel-like structure. Polyelectrolyte and surfactants can yield highly mesostructured films using simple buildup strategies as layer-by-layer. The use of redox modified surfactants is expected to introduce order and an electroactive response in thin films.

EXPERIMENTS

The assembly of polyacrylic acid and different combinations of redox-modified and unmodified hexadecyltrimethylammonium bromide yields highly structured and electroactive thin films. The growth, viscoelastic properties, mass, and electron transport of these films were studied by combining electrochemical and quartz crystal balance with dissipation experiments.

FINDINGS

Our results show that the films are highly rigid and poorly hydrated. The mass and charge transport reveal that the ingress (egress) of the counter ions during the electrochemical oxidation (reduction) is accompanied with a small amount of water, which is close to their hydration sphere. Thus, the generated mesostructured films present an efficient charge transport with negligible changes in their structures during the electron transfer process. The control over the meso-organization and its stability represents a promising tool in the construction of devices where the vectorial transfer of electrons, or ions, is required.

Ionic-surfactants-based thermotropic liquid crystals

Ionic surfactants can be combined with various functional groups through electrostatic interaction, resulting in a series of thermotropic liquid crystals (TLCs).

Solvent Effects on the Structure-Property Relationship of Redox-Active Self-Assembled Nanoparticle-Polyelectrolyte-Surfactant Composite Thin Films: Implications for the Generation of Bioelectrocatalytic Signals in Enzyme-Containing Assemblies

The search for strategies to improve the performance of bioelectrochemical platforms based on supramolecular materials has received increasing attention within the materials science community, where the main objective is to develop low-cost and flexible routes using self-assembly as a key enabling process. Important contributions to the performance of such bioelectrochemical devices have been made based on the integration and supramolecular organization of redox-active polyelectrolyte-surfactant complexes on electrode supports. Here, we examine the influence of the processing solvent on the interplay between the supramolecular mesoorganization and the bioelectrochemical properties of redox-active self-assembled nanoparticle-polyelectrolyte-surfactant nanocomposite thin films. Our studies reveal that the solvent used in processing the supramolecular films and the presence of metal nanoparticles not only have a substantial influence in determining the mesoscale organization and morphological characteristics of the film but also have a strong influence on the efficiency and performance of the bioelectrochemical system. In particular, a higher bioelectrochemical response is observed when nanocomposite supramolecular films were cast from aqueous solutions. These observations seem to be associated with the fact that the use of aqueous solvents increases the hydrophilicity of the film, thus favoring the access of glucose, particularly at low concentrations. We believe that these results improve our current understanding of supramolecular nanocomposite materials generated via polyelectrolyte-surfactant complexes, in order to use the processing conditions as a variable to improve the performance of bioelectrochemical devices.