TY - JOUR
T1 - Molecular dynamics simulations of surfactant and nanoparticle self-assembly at liquid-liquid interfaces
AU - Luo, Mingxiang
AU - Dai, Lenore L.
N1 - Funding Information:
We thank the Texas Tech High Performance Computing Center (HPCC) for computational resources. We are also grateful for the financial support from the National Science Foundation (CBET-0625191).
Publisher Copyright:
© 2007 IOP Publishing Ltd Printed in the UK.
PY - 2007/8
Y1 - 2007/8
N2 - We have performed molecular dynamics (MD) simulations to investigate selfassembly at water-trichloroethylene (TCE) interfaces with the emphasis on systems containing modified hydrocarbon nanoparticles (1.2 nm in diameter) and sodium dodecyl sulfate (SDS) surfactants. The nanoparticles and surfactants were first distributed randomly in the water phase. The MD simulations have clearly shown the progress of migration and final equilibrium of the SDS molecules at the water-TCE interfaces with the nanoparticles either at or in the vicinity of the interfaces. One unique feature is the 'attachment' of surfactant molecules to the nanoparticle clusters in the water phase followed by the 'detachment' at the water-TCE interfaces. At low concentrations of surfactants, the surfactants and nanoparticles co-equilibrate at the interfaces. However, the surfactants, at high concentrations, competitively dominate the interfaces and deplete nanoparticles away from the interfaces. The interfacial properties, such as interfacial thickness and interfacial tension, are significantly influenced by the presence of the surfactants, but not the nanoparticles. The order of the surfactants at the interfaces increases with increasing surfactant concentration, but is independent of nanoparticle concentration. Finally, the simulation has shown that surfactants can aggregate along the water-TCE interfaces, with and without the presence of nanoparticles.
AB - We have performed molecular dynamics (MD) simulations to investigate selfassembly at water-trichloroethylene (TCE) interfaces with the emphasis on systems containing modified hydrocarbon nanoparticles (1.2 nm in diameter) and sodium dodecyl sulfate (SDS) surfactants. The nanoparticles and surfactants were first distributed randomly in the water phase. The MD simulations have clearly shown the progress of migration and final equilibrium of the SDS molecules at the water-TCE interfaces with the nanoparticles either at or in the vicinity of the interfaces. One unique feature is the 'attachment' of surfactant molecules to the nanoparticle clusters in the water phase followed by the 'detachment' at the water-TCE interfaces. At low concentrations of surfactants, the surfactants and nanoparticles co-equilibrate at the interfaces. However, the surfactants, at high concentrations, competitively dominate the interfaces and deplete nanoparticles away from the interfaces. The interfacial properties, such as interfacial thickness and interfacial tension, are significantly influenced by the presence of the surfactants, but not the nanoparticles. The order of the surfactants at the interfaces increases with increasing surfactant concentration, but is independent of nanoparticle concentration. Finally, the simulation has shown that surfactants can aggregate along the water-TCE interfaces, with and without the presence of nanoparticles.
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U2 - 10.1088/0953-8984/19/37/375109
DO - 10.1088/0953-8984/19/37/375109
M3 - Article
AN - SCOPUS:85043564800
SN - 0953-8984
VL - 19
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 37
M1 - 375109
ER -