Interacting Surfaces (interactingSurfaces.pre)

Keywords:

confinement, phase transition

Problem description

This simulation can be performed with a PSimPlus license.

This example explores the effects of structured interacting surfaces on coplymer morphology. It demonstrates the python function for specifying geometry.

Input File Features

Files: interactingSurfaces.pre.

The variables in the Setup tab are

  • NX (Number of cells in the x-dir)
  • NY (Number of cells in the y-dir)
  • NZ (Number of cells in the z-dir)
  • fA (Length fraction of ‘A’ block)
  • fB (Length fraction of ‘B’ block)
  • chiNAB (Flory chi parameter) between the two chemically distinct blocks of the confined copolymer chains
  • chiNWA (Flory parameter) Interaction parameter between the A monomers and bottom wall surface
  • chiNWB (Flory parameter) Interaction parameter between the B monomers and bottom wall surface
  • SINE_AMPL (Wall shape parameter) Amplitude of sine function defining bottom wall
  • SINE_FREQ (Wall shape paramter) Frequency of sine function defining bottom wall

Creating the run space

The Interacting Surfaces example is accessed from within PSimComposer by the following actions:

  • Select the New from Template menu item in the File menu.
  • In the resulting New from Template window, select PSimPlus and then press the arrow button to the left.
  • Select “Interacting Surfaces” and press the Choose button.
  • In the resulting dialog, press the Save button to create a copy of this example in your run area.

The basic variables of this problem should now be settable in text boxes in the right pane of the “Setup” window, as shown in Fig. 81.

../../../_images/interactingSurfacesSetupWin.png

Figure 81: Setup window for the Interacting Surfaces example.

Running the simulation

After performing the above actions, continue as follows:

  • Press the Save And Setup button in the upper right corner.
  • Proceed to the run window as instructed by pressing the Run button in the left column of buttons.
  • Note: because the initial random state depends on the number of processors, the final simulation state can depend on the number of processors chosen if running in parallel. The results in this example are produced by running on two processors. The parallel run options can be accessed by going to the ‘MPI’ tab on the left side of the Run button window.
  • To run the file, click on the Run button in the upper right corner of the window. You will see the output of the run in the right pane. The run has completed when you see the output, “Engine completed successfully.” This is shown in Fig. 82.
../../../_images/interactingSurfacesRunWin.png

Figure 82: The Run window at the end of execution.

Visualizing the results

After performing the above actions, continue as follows:

  • Proceed to the Visualize window as instructed by pressing the Visualize button in the left column of buttons.
  • Press the “Open” button to begin visualizing.
  • Go to the Scalar Data Variable in the CONTROLS panel on the left and press the arrow to the left
  • Check one of the MonomerDensity boxes (try the totEthyDens database) This selects all of the datafiles for this physical field ‘totEthyDens’. This first *h5 file will be shown first.
  • Move the Dump slider at the bottom of the window to the last position to see the final simulation state.
  • Choose the Colors button at the top of the Visualization pane and select ‘hot_desaturated’ palette to match the Fig. 83.
../../../_images/interactingSurfacesVizWin.png

Figure 83: Visualization of Interacting Surfaces as a color contour plot.

Further Experiments

Change the wall interaction parameters to see how the morphologies are effected.

Change the ‘sine amplitude’ and ‘sine frequency’ bottom wall parameters to see how the structure of the wall effects the morphologies.