Influences of alcohol and diol on the aggregation behaviour, modes of interaction and the thermodynamic properties of the mixture of bromocresol green dye and sodium dodecyl sulphate at numerous temperatures

Abstract

The aggregation of the mixture of anionic surfactant – sodium dodecyl sulfate (SDS), and an anionic dye – bromocresol green sodium salt (BCG) was investigated by conductometric technique in water and alcoholic/diolic media within a temperature range of 300.55–320.55 K (with 5 K interval). The observed critical micelle concentration (cmc) decreases with surging of the concentration of BCG, following the same trend for β value. In presence of additives (ethanol, propanol, and ethylene glycol), the cmc value decreases up to a certain concentration and then the cmc values start enhancing with increasing concentration in all the cases. With the increased additive percentage, the β values continually decrease. Again, the cmc value increases gradually with the increase of temperature both in water and aq. additives media. The free energy of studied aggregation phenomena is negative which experiences an augmentation with the escalation of temperature. The increased negative value of free energy at elevated temperature indicates that the process becomes more spontaneous at a higher temperature. The $\mathrm{\Delta }{H}_m^0$ and $\mathrm{\Delta }{S}_m^0$ values reveal that the probable interaction forces between BCG and SDS are hydrophobic, ion-ion, as well as electrostatic interactions.

GRAPHICAL ABSTRACT

KEYWORDS:

• Anionic surfactant (SDS)
• anionic dye (BCG)
• micelle
• cmc
• thermodynamic parameters

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are grateful to the Deanship of Scientific Research, King Saud University for funding through Vice Deanship of Scientific Research Chairs and this research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding Program.