title: Unveiling One-Dimensional Supramolecular Structures Formed through π-π Stacking of Phenothiazines by Differential Pulse Voltammetry.
abstract: Organic-based nanomaterials can be self-assembled by strong and directional intermolecular forces such as π-π interactions. Experimental information about the stability, size, and geometry of the formed structures is very limited for species that easily aggregate, even at very low concentrations. Differential pulse voltammetry (DPV) can unveil the formation, growth, and also the stability window of ordered, one-dimensional, lamellar self-aggregates formed by supramolecular π stacking of phenothiazines at micromolar (10-6mol L-1) concentrations. The self-diffusion features of the species at different concentrations are determined by DPV and used to probe the π staking process through the concept of the frictional resistance. It is observed that toluidine blue and methylene blue start to self-aggregate around 9 μmol L-1, and that the self-aggregation process occurs by one-dimensional growth as the concentration of the phenothiazines is increased up to around 170 μmol L-1for toluidine blue and 200 μmol L-1for methylene blue. At higher concentrations, the aggregation process leads to structures with lower anisometry.
authors.affiliation: Department of Chemstry, State University of Maringa, Av. Colombo 5790-CE, 87020-90, Maringá, Paraná, Brazil.
authors.forename: Fernando R
authors.initials: FR
authors.lastname: Carvalho
authors.affiliation: Department of Chemstry, State University of Maringa, Av. Colombo 5790-CE, 87020-90, Maringá, Paraná, Brazil.
authors.forename: Eduardo H
authors.initials: EH
authors.lastname: Zampieri
authors.affiliation: Department of Chemstry, State University of Maringa, Av. Colombo 5790-CE, 87020-90, Maringá, Paraná, Brazil.
authors.forename: Wilker
authors.initials: W
authors.lastname: Caetano
authors.affiliation: Department of Chemstry, State University of Maringa, Av. Colombo 5790-CE, 87020-90, Maringá, Paraná, Brazil.
authors.forename: Rafael
authors.identifier: http://orcid.org/0000-0002-1591-3772
authors.initials: R
authors.lastname: Silva
keywords: differential pulse voltammetry; diffusion coefficients; molecular stacking; one-dimensional organic clusters; phenothiazines