Embed Size (px)
Citation preview
CREATING THIN LIQUID LAYERSAT THE CONTACT SURFACE OF TWO
OTHER LIQUIDS
Agnieszka Słowicka
Zbigniew A. Walenta
Institute of Fundamental TechnologicalResearch
Polish Academy of Sciences
Aim- Nanomaterials of structure as shown
The emulsion with thin layers of third substanceat the surface between oil and water
The structure of nanomaterial after removingwater and oil
Molecular Dynamics Simulation
Liquid – an ensemble of molecules
Interaction between molecules
Electrostatic interaction van der Waals interaction
Coulomb potential Lennard - Jones potential
The program „Moldy” by Keith Refson used for simulation.
])()[()( 612 rrrU
Diagram of Lennard-Jones potential
r - distance between molecules , - parameters of L-J potential
2112 2
2112
Formula for different molecules parameters
t = 0 ps
Molecules of water = 1000
Diameter of the droplet ~A 38
Formation of water droplet in vacuum
t = 8 ps t = 40 ps
+
H
O
16 amu
1 amu+
H
Molecule of water
= 0.51799 = 3.2407
Molecules of water = 10648
Diameter of the droplet ~A 84
t = 0 ps
t = 16 ps
w = 1024
D ~
A 38
t = 0 ps
t = 26 ps
Simulation of emulsification process
t = 0 ps
t = 5ps t = 13ps
180 amu
Model of oil
= 0.051799 = 3.2407
O O
Oil 180 amu
16 amu
36 amu
Na+
+
Simulation of three liquids:”short” soap
t = 46ps t = 48ps
60 amu
180 amu 180 amu
”Long” soap: creating of layer
t = 45ps t = 0ps
Simulation of two liquids and solid
t = 0 ps t = 115 ps t = 165 ps
Carbon
12 amu
= 0.4257 = 3.35
t = 0 ps t = 100 ps t = 500 ps
weak interactions between oil and carbon
Quasi-Carbon
12 amu
Conclusions
•The molecular dynamics seems to be the best tool to simulate physicalprocesses on a nanoscale in liquids.
•Formation of water droplet in vacuum and oil droplet in water havebeen simulated successfully.
•The use of soap as a substance, which would concentrate at theinterface between water and oil has been tested.
•Good results were obtained only for soaps with long hydrophobic partof the molecule.
•Now we look for solid substances, which would stay at the surface of the droplets and would not mix with oil..
