Influences of surfactant and nanoparticle assembly on effective interfacial tensions

Abstract

We have studied assembly at air-water and liquid-liquid interfaces with an emphasis on systems containing both surfactants and nanoparticles. Anionic surfactants, sodium dodecyl sulfate (SDS) and non-ionic surfactants, Triton X-100 and tetraethylene glycol alkyl ethers (C(8)E(4), C(12)E(4) and C(14)E(4)), effectively decrease the surface tension of air-water interfaces. The inclusion of negatively charged hydrophilic silica nanoparticles (diameters of approximately 13 nm) increases the efficiency of the SDS molecules but does not alter the performance of the non-ionic surfactants. The former is likely due to the repulsive Coulomb interactions between the SDS molecules and nanoparticles which promote the surfactant adsorption at air-water interfaces. For systems involving trichloroethylene (TCE)-water interfaces, the SDS and Triton X-100 surfactants effectively decrease the interfacial tensions and the nanoparticle effects are similar compared to those involving air-water interfaces. Interestingly, the C(12)E(4) and C(14)E(4) molecules, with or without the presence of nanoparticles, fail to decrease the TCE-water interfacial tensions. Our molecular dynamics simulations have suggested that the tetraethylene glycol alkyl ether molecules tend to disperse in the TCE phase rather than adsorb at the TCE-water interfaces.

Heat of adsorption of surfactants and its role on nanoparticle stabilization

“…In the case of surfactant-coated nanoparticles the structure of the surfactant tail and head group play an important role on the stability of the nanoparticles. Previous studies on the interaction between surfactant and iron nanoparticles have involved the use of various techniques such as surface tension [4,5], thermogravimetric analysis [6][7][8], and Fourier transform infrared spectroscopy (FTIR) [7,8]. The results from those studies suggest that a bilayer is formed on the particles at high surfactant concentrations [5][6][7].…”

Enhancement of surfactant flooding performance by the use of silica nanoparticles

“…a r t i c l e i n f o 23 Article history: 24 Received 11 August 2013 25 Received in revised form 11 November 2014 26 Accepted 13 November 2014 27 Available online xxxx 28 Keywords: 29 Enhanced oil recovery 30 Hydrophilic silica nanoparticle 31 Slightly hydrophobic silica nanoparticle 32 Surfactant adsorption 33 Interfacial tension 34 3 5 a b s t r a c t 36 One of the most significant current discussions in petroleum industry is the use of nanotechnology to 37 improve oil recovery. The aim of this study is the implication of silica nanoparticles in combination with 38 anionic surfactant to see if the surfactant properties are influenced in the presence of nanoparticles and to 39 investigate the capability of these particles to enhance oil recovery.…”

Self-assembly of amphiphilic molecules: A review on the recent computer simulation results

“…In addition to aggregate on solid surface, the adsorption behaviors of amphiphilic molecules at other interfaces, such as oil-water interface [42][43][44][45][46], liquid-vapor interface [47][48][49][50][51][52], are also studied in recent years.…”