Synergistic Effects of Mixed Aromatic Counterions on Nanostructures and Drag Reducing Effectiveness of Aqueous Cationic Surfactant Solutions

Abstract

Drag reduction effectiveness of two dilute quaternary ammonium surfactant aqueous solutions with different pairs of mixed aromatic counterions was investigated along with their micellar nanostructures revealed by cryo-TEM imaging, zeta potential, particle size, and (1)H NMR measurements. Certain combinations of aromatic counterion mixtures showed significant synergistic effects. They dramatically improved drag reduction effectiveness relative to either single aromatic counterion. Using mixed aromatic counterions with different sizes and binding abilities, the effective drag reducing temperature range can be significantly expanded and higher shear stress stability can be achieved. The synergistic effects are believed to be induced by increased degree of branching in the surfactant micellar networks as shown by cryo-TEM images.

Review on Drag Reduction and Its Heat Transfer by Additives

“…Thus, cationic surfactants can have wide temperature ranges suitable for both district heating and cooling systems. The effects of mixed counterions were similar but less dramatic [11,172,176].…”

“…Sodium salicylate is the most widely studied counterion. Chou et al [171, 174] found that an Ethoquad O-12/sodium salicylate solution at a molar ratio of 1.5 : 1 showed most effective drag reduction at 2°C. Excess quantities of sodium salicylate (0.2 wt.%) in the cetyl trimethyl ammonium salicylate (CTASal) system (0.2 wt.%) were observed by Rose et al [168, 170] to increase the critical Reynolds number (from about 20000 to about 50000) and the critical temperature (from 50°C to 70°C).…”

“…Chou [174] and Ge et al [13, 176] observed increased drag reduction temperature ranges with certain mixtures of counterions. Chou et al [169, 174] proposed a number of counterions that may be very effective at temperatures between 40°C and 90°C.…”

Going against the flow—A review of non-additive means of drag reduction

“…Additionally, nonionic surfactants have been proven to be effective for a limited range of temperatures and concentrations only [29][30][31]. Cationic surfactants performance as DRAs have been tested extensively by many researchers, especially when they are combined with a suitable counter-ion [32][33][34][35][36]15]. The presence of the counter-ion will help the cationic surfactants to form long rod-like micelles by dispersing the head group charge.…”

Influence of Surfactants on the Fluorescein Fluorescence Properties

“…З одного боку ПАР є аналітичними реагентами, а з іншого -здатні ефективно впливати на фізико-хімічні властивості інших речовин у розчинах. Відомо [2,3], що використання міцелярних систем дає можливість збільшити квантові виходи у 2-10 разів, інтенсивність флюоресценції в 3-80 разів, і, відповідно, знизити межі виявлення аналітів на 1-2 порядки. Організовані середовища на основі ПАР впливають на флюоресценцію люмінесцентних індикаторів та їх комплексних сполук завдяки зміні у міцелярному розчині їхніх фотофізичних характеристик, агрегатного стану та характеру мікрооточення [4,5].…”