# Characterization of a Commercial Anion-Exchange Membrane Modified with Electrosynthesized Polyaniline Deposits at Different Temperatures

## TL;DR

This paper studies how modifying a membrane with polyaniline at different temperatures affects its ionic transport and selectivity properties.

## Contribution

The study introduces a method to modify anion-exchange membranes with polyaniline at varying temperatures and analyzes the resulting changes in membrane properties.

## Key findings

- Permselectivity increases with higher synthesis temperatures (0.757 to 0.808).
- Contact angle decreases with higher synthesis temperatures, indicating increased hydrophilicity.
- Morphological changes in polyaniline deposits explain the observed property trends.

## Abstract

Phenomena associated with an ion-exchange membrane (IEM) in contact with an ionic solution, such as its selectivity and ionic transport, commonly occur when an ion approaches the membrane surface. Because of this, if a change occurs in the IEM/Solution interfacial region, then it is expected that these processes will be affected. For example, if the IEM surface is modified with an electronic conducting polymer (ECP), then its selectivity and the phenomena associated with ionic transport will change. These changes can be quantified by parameters such as the permselectivity, the contact angle, and others, and are associated with the hydrophilic/hydrophobic balance of its surface. This work reports the characterization of commercial anion-exchange membrane samples modified voltammetrically with polyaniline (PAni) obtained at different temperatures (10, 15, and 20 °C). Among the main results obtained, it was found that with an increase in synthesis temperature of the PAni, the membrane’s permselectivity will increase from 0.757 to 0.782 to 0.808. While contrary behavior is observed in the case of the contact angle, since an increase in the synthesis temperature will cause a greater hydrophilic character when going from 67° to 53° to 50°. According to this work, these trends in the properties of the modified membranes are related to the morphological characteristics of PAni deposits conferred by the variation in the synthesis temperature.