Abstract
This paper presents the effect of some electrolytes on the Krafft temperature (T K) of cetylpyridinium chloride in aqueous solution. The results show that more chaotropic anions raise while less chaotropic anions lower the T K of the surfactant. More chaotropic Br−, SCN− and I− form contact ion pairs with the cetylpyridinium ion and reduce the electrostatic repulsion between the surfactant molecules. As a result, these ions exhibit salting-out behavior, showing an increase in the T K of the surfactant. On the other hand, less chaotropic NO3 − increase the solubility of the surfactant, with a consequent decrease in the T K. Surface tension data of the salt solutions reveal that more chaotropic ions show a relatively less molar increase in surface tension compared to less chaotropic ions. This indicates that less chaotropic ions have a preferential tendency to be negatively adsorbed at the air–water interface as well as hydrocarbon–water interface and thereby disturb the hydration of the surfactant. SO4 2− being a strong kosmotrope cannot form contact ion pairs with the cationic part of the surfactant. Rather this ion preferentially remains in the bulk because of its strong tendency for hydration and thereby stays apart. As a result, SO4 2− also causes a significant lowering of the T K of the surfactant. Thus it appears that contrary to the usual trend SO4 2− behave like a chaotrope showing salting-in effect of the surfactant.
Similar content being viewed by others
References
Myers D (2004) Surfactant science and technology, 3rd edn. Wiley Interscience, Hoboken
Rosen MJ (2006) Surfactants and interfacial phenomena, 3rd edn. Wiley Interscience, Hoboken
Tsuji K, Mino J (1978) Krafft point depression of some zwitterionic surfactants by inorganic salts. J Phys Chem 82:1610–1614
Chu Z, Feng YJ (2012) Empirical correlations between Krafft temperature and tail length for amidosulfobetaine surfactants in the presence of inorganic salt. Langmuir 28:1175–1181
Nakayama H, Shinoda K (1967) The effect of added salts on the solubilities and Krafft points of sodium dodecyl sulfate and potassium perfluoro-octanoate. Bull Chem Soc Jpn 40:1797–1799
Blanco E, González-Pérez A, Ruso JM, Pedrido R, Prieto G, Sarmiento F (2005) A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles. J Colloid Interface Sci 288:247–260
Shinoda K, Yamaguchi N, Carlsson A (1989) Physical meaning of the Krafft point: observation of melting phenomenon of hydrated solid surfactant at the Krafft point. J Phys Chem 93:7216–7218
Diamant H, Andelman D (1996) Kinetics of surfactant adsorption at fluid–fluid interfaces. J Phys Chem 100:13732–13742
Iglauer S, Wu Y, Shuler P, Tang Y, Goddard WA (2010) New surfactant classes for enhanced oil recovery and their tertiary oil recovery potential. J Petrol Sci Eng 71:23–29
Vijayan S, Ramachandran C, Shah DO (1981) Effect of salt and aging on surfactant formulation for enhanced oil recovery: a correlation of physical properties with macrostructure using spin-labels. J Am Oil Chem Soc 58:566–573
Carolina V-G, Bales BL (2003) Estimate of the ionization degree of ionic micelles based on Krafft temperature measurements. J Phys Chem B 107:5398–5403
Bakshi MS, Sood R (2004) Cationic surfactant–poly(amido amine) dendrimer interactions studied by Krafft temperature measurements. Colloids Surf A 233:203–210
Mesa CL, Ranieri GA, Terenzi M (1988) Studies on Krafft point solubility in surfactant solutions. Thermochim Acta 137:143–150
Bostrom M, Kunz W, Ninham BW (2005) Hofmeister effects in surface tension of aqueous electrolyte solution. Langmuir 21:2619–2623
Jarvis NL, Schelman MA (1968) Surface potentials of aqueous electrolyte solutions. J Phys Chem 72:74–78
Pegram LM, Record MTJ (2007) Hofmeister salt effects on surface tension arise from partitioning of anions and cations between bulk water and the air–water interface. J Phys Chem 111:5411–5417
Zhang Y, Cremer PS (2010) Chemistry of Hofmeister anions and osmolytes. Annu Rev Phys Chem 61:63–83
Gurau MC, Lim S-M, Castellana ET, Albertono F, Kotaoka S, Cremer PS (2004) On the mechanism of the Hofmeister effect. J Am Chem Soc 126:10522–10523
Nishikido N, Matauura R (1977) The effect of added inorganic salts on the micelle formation of micelle formation in aqueous solution. Bull Chem Soc Jpn 50:1690–1694
Zhang Y, Furyk S, Bergbreiter DE, Cremer PS (2005) Specific ion effects on the water solubility of macromolecules: PNIPAM and the Hofmeister series. J Am Chem Soc 127:14505–14510
Collins KD (2012) Why continuum electrostatics theories cannot explain biological structure, polyelectrolytes or ionic strength effects in ion–protein interactions. Biophys Chem 167:43–59
Collins KD, Neilson GW, Enderby JE (2007) Ions in water: characterizing the forces that control chemical processes and biological structure. Biophys Chem 128:95–104
Lee JD Inorganic chemistry, ELBS, 4th edn
Cheng J, Vecitis CD, Hoffmann MR, Colussi AJ (2006) Experimental anion affinities for the air/water interface. J Phys Chem 110:25598–25602
Mason PE, Neilson GW, Dempsey CE, Barnes AC, Cruickshank JM (2003) The hydration structure of guanidinium and thiocyanate ions: implications for protein stability in aqueous solution. Proc Nat Acad Sci 100:4557–4561
Zhang Y, Cremer PS (2009) The inverse and direct Hofmeister series for lysozyme. Proc Nat Acad Sci 106:15249–15253
Bostrom M, Tavares FW, Finet S, Skouri-Panet F, Tardieu A, Ninham BW (2005) Why forces between proteins follow different Hofmeister series for pH above and below pI. Biophys Chem 117:217–224
Endom L, Hertz HG, Thul B, Zeidler MD (1967) A microdynamic model of electrolyte solutions as derived from nuclear relaxation and self-diffusion data. Dtsch Bunsenges Phys Chem 71:1008–1031
Glasstone S (1947) Thermodynamics for chemists, 3rd edn, Litton Educational Publishing, New York
Roy JC, Islam MN, Aktaruzzaman G (2014) The effect of NaCl on the Krafft temperature and related behavior of cetyltrimethylammonium bromide in aqueous solution. J Surf Deterg 17:231–242
Chen X, Sarah C, Flores SC, Lim S-M, Zhang Y, Yang T, Kherb J, Cremer PS (2010) Specific anion effects on water structure adjacent to protein monolayers. Langmuir 26:16447–16454
Zhang L, Somasundaran P, Maltesh C (1996) Electrolyte effects on the surface tension and micellization of n-dodecyl β-d-maltoside solutions. Langmuir 12:2371–2373
Margolis EM. Chemical principles in calculations of ionic equilibria, Macmillan, New York, p 45
Acknowledgments
Authors thank the members of the Board of Postgraduate Studies for helpful discussion during the preparation of the research proposal. The financial assistance (CASR-236/32) approved by the Committee for Advanced Studies and Research (CASR), BUET for carrying out the present work is highly appreciated.
Author information
Authors and Affiliations
Corresponding author
Electronic Supplementary Material
Below is the link to the electronic supplementary material.
About this article
Cite this article
Nazrul Islam, M., Sarker, K.C. & Aktaruzzaman, G. Effect of Electrolytes on the Krafft Temperature of Cetylpyridinium Chloride in Aqueous Solution. J Surfact Deterg 17, 525–530 (2014). https://doi.org/10.1007/s11743-014-1577-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11743-014-1577-2