Aggregation of methyl orange probed by electrical impedance spectroscopy

Area of Science:

• Physical Chemistry
• Materials Science

Background:

• Dye aggregation significantly influences solution properties.
• Understanding aggregation is crucial for applications involving dyes and surfactants.

Purpose of the Study:

• To investigate the aggregation of methyl orange (MO) in aqueous solutions using electrical impedance spectroscopy (EIS).
• To identify specific dielectric signatures associated with MO dimer and oligomer formation.

Main Methods:

• Electrical impedance spectroscopy (EIS) was employed to analyze MO solutions at varying concentrations.
• The constant phase element (CPE) approximation was used to model the electrical response.

Main Results:

• Specific signatures were observed in the loss and capacitive components of the dielectric response, correlating with MO aggregation.
• Changes in dielectric properties were linked to molecular rearrangements and altered current pathways during aggregation.
• Observed dielectric changes coincided with known critical concentrations for MO dimer and oligomer formation.

Conclusions:

• EIS can effectively detect and characterize methyl orange aggregation in aqueous solutions.
• The technique provides a competitive and sensitive method for studying aggregation phenomena in dyes and surfactants.