Monte Carlo Simulation for Ternary System of Water/Oil/ABA Triblock Copolymers

摘要

We performed Monte Carlo simulation of water/oil/ABA triblock amphiphiles with hydrophilic A and hydrophobic B, on a 51×51×51 simple cubic lattice with periodic boundary conditions in x- and y-directions. Bond fluctuation model(BFM) was used to describe amphiphile, where excluded volume effect and flexible movement of polymer bonds are ascertained. The ratio of water to oil was changed from 10/85 to 50/45 with 5% fixed dilute amphiphiles. For small water/oil ratio, many cubic water clusters surrounded by loop-shaped amphiphiles dispersed in oil and they were bridged between each other by bridge-shaped amphiphiles. On the other hand, phase separation between water and oil plus amphiphiles clearly occurred for large water/oil ratio, where water formed one grid-shaped cluster. At some intermediate water/oil ratio, water cells aggregated into two water clusters with shape of rectangular rod, spread in x- and y-directions and separated in z-direction by mainly loop-shaped amphiphiles, where water clusters and oil plus amphiphiles formed layers perpendicular to z-direction.