Modifying Properties of Aqueous Cetyltrimethylammonium Bromide with External Additives: Ionic Liquid 1-Hexyl-3-methylimidazolium Bromide versus Cosurfactant n-Hexyltrimethylammonium Bromide

Abstract

Understanding the effect of external additives on the properties of aqueous surfactant solutions is of utmost importance due to widespread applications of surfactant-based systems. Role of ionic liquids (ILs) in this regard may turn out to be crucial as these substances are known to possess unusual properties. To unambiguously understand and establish the role of ILs in modifying properties of aqueous surfactant systems, changes in the physicochemical properties of aqueous cetyltrimethylammonium bromide (CTAB) upon addition of an IL 1-hexyl-3-methylimidazolium bromide ([hmim][Br]) are compared with those when a cosurfactant n-hexyltrimethylammonium bromide (HeTAB) is added to aqueous CTAB. Important physicochemical properties, such as critical micelle concentration (cmc), aggregation number (N(agg)), solution conductance and microfluidity, and average aggregate size and polydispersity, are observed to change as either [hmim][Br] or HeTAB is added to aqueous CTAB; the experimental outcomes clearly imply the changes in most of the physicochemical properties to be significantly more dramatic in case of IL [hmim][Br] addition. The fact that, between the two, only IL [hmim][Br] may show cosolvent-type behavior at high concentrations is evoked to explain the differences in the behavior of the two additives. It is demonstrated that both [hmim][Br] and HeTAB show electrolytic as well as cosurfactant-type behavior within aqueous CTAB when present at low concentrations, with the changes in physicochemical properties being very similar. At high concentrations, although HeTAB still acts as a cosurfactant forming mixed micelles with CTAB, IL [hmim][Br] behaves partly as a cosolvent toward altering the physicochemical properties of aqueous CTAB. The unique role of IL in changing properties of aqueous surfactant systems is demonstrated.

Effect of [C n mim][Br] Based Ionic Liquids on the Aggregation Behavior of Tetradecyltrimethylammonium Bromide in Aqueous Medium

“…with n = 6 and 8) and anions [Br -] in the solution after dissociation. Pandey's group has reported similar conductivity behavior for cationic, anionic and non-ionic surfactants such as CTAB [51], SDS [25,26] and Tirton X-100 [23,24]. At fixed concentration of SDS, cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), Pal (Fig.…”

“…While selecting TTAB as the surfactant, we are studying the influence of the investigated ILs on the alkyl chain of the single chain cationic surfactant by comparing the new results with already published results for CTAB [51]. In this respect, here we investigate the affects of concentration and alkyl chain length of ILs in changing the physicochemical properties of the aqueous TTAB solution.…”

Interactions of new 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) based surface active ionic liquids with amitriptyline hydrochloride: Micellization and interfacial studies

“…With the possibility of finetuning the amphiphilicity of ILs by changing the alkyl chain length or polarizability of the cation and anion, one can generate specific self-assembled structures. The self-assembling behaviour of ILs has been a focus of many recent investigations [8][9][10][11][12][13][14][15]. But most of the papers have reported the aggregation behaviour of imidazolium based SAILs with different hydrophobic alkyl chains and anions [8][9][10][11][12].…”

Catanionic surfactant formation from the interaction of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) and the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate (bmim-octyl SO4) in aqueous solution

“…The effect of the ionic liquid on the surfactant properties depends on the IL structure and concentration. Behera and Pandey [1,4,8] reported that at low concentration some ILs act similarly to an electrolyte decreasing the surfactant cmc whereas at high concentration they behave as a cosolvent increasing this parameter. In the case of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) the effect of ILs on the surfactant cmc confirms the trend above described [8][9][10][11][12][13].…”

“…Behera and Pandey [1,4,8] reported that at low concentration some ILs act similarly to an electrolyte decreasing the surfactant cmc whereas at high concentration they behave as a cosolvent increasing this parameter. In the case of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) the effect of ILs on the surfactant cmc confirms the trend above described [8][9][10][11][12][13]. However, when IL posses surface activity as reported for long alkyl chain ionic liquids [14][15][16][17][18][19][20][21] and some short alkyl chain ILs [22,23] the ionic liquid / surfactant mixture behaves as a typical binary surfactant system [24][25][26].…”