TY - JOUR

T1 - Self-assembly based on hydrotropic counterion - Single-chain amphiphile ion pairs

AU - Rosholm, Kadla R.

AU - González-Pérez, Alfredo

AU - Mouritsen, Ole G.

PY - 2010/10/1

Y1 - 2010/10/1

N2 - We investigate the effect of organic hydrotropic counterions on the self-assembled structures formed by pure counterion-single-chain amphiphile ion pairs. The effect of inorganic counterions on singlechain amphiphiles has been studied for years, taking into account the Hofmeister series that directly affects the micellization. Here, hexadecyldimethylbenzylammonium salicylate (C16Sal) in aqueous solution is used as a model for the influence of organic counterions, and the results have been compared with those previously published for inorganic counterions, specifically hexadecyldimethylbenzylammonium chloride (C16Cl). The studies have been performed by using conductivity, dynamic light scattering, as well as atomic force microscopy. We demonstrate the formation of vesicles and suggest the presence of a vesicle-to-micelle transition at higher concentrations. The Gibbs free energy associated with the self-assembly process has been estimated on the basis of the well-known massaction model. The main conclusion is that the use of hydrotropic counterions instead of classical inorganic ions dramatically changes the packing parameter of singlechain amphiphiles to higher values, resulting in bilayer structures. We propose that these systems are good and cheap alternatives to double-chain amphiphiles for forming more complex structures like vesicles.

AB - We investigate the effect of organic hydrotropic counterions on the self-assembled structures formed by pure counterion-single-chain amphiphile ion pairs. The effect of inorganic counterions on singlechain amphiphiles has been studied for years, taking into account the Hofmeister series that directly affects the micellization. Here, hexadecyldimethylbenzylammonium salicylate (C16Sal) in aqueous solution is used as a model for the influence of organic counterions, and the results have been compared with those previously published for inorganic counterions, specifically hexadecyldimethylbenzylammonium chloride (C16Cl). The studies have been performed by using conductivity, dynamic light scattering, as well as atomic force microscopy. We demonstrate the formation of vesicles and suggest the presence of a vesicle-to-micelle transition at higher concentrations. The Gibbs free energy associated with the self-assembly process has been estimated on the basis of the well-known massaction model. The main conclusion is that the use of hydrotropic counterions instead of classical inorganic ions dramatically changes the packing parameter of singlechain amphiphiles to higher values, resulting in bilayer structures. We propose that these systems are good and cheap alternatives to double-chain amphiphiles for forming more complex structures like vesicles.

KW - Atomic force microscopy

KW - Conductivity

KW - Dynamic light scattering

KW - Hydrotropic counterion

KW - Single-chain amphiphile

KW - Vesicle

KW - Vesicle-to-micelle transition

UR - http://www.scopus.com/inward/record.url?scp=84856443228&partnerID=8YFLogxK

U2 - 10.1007/s00396-010-2241-7

DO - 10.1007/s00396-010-2241-7

M3 - Review

AN - SCOPUS:84856443228

VL - 288

SP - 1351

EP - 1357

JO - Colloid and Polymer Science

JF - Colloid and Polymer Science

SN - 0303-402X

IS - 14-15

ER -