Neutral Pore Confinement (neutralPoreConfine.pre)


phase transition, confinement

Problem description

This simulation can be performed with a PSimPlus license.

This example shows the effects of confinement on morphologies of a system of AB diblock polymer chains in a cylindrical pore with walls that have neutral energetic interactions with the monomers on the copolymer chains.

Input File Features

Files: neutralPoreConfine.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)
  • xs_CYLRADIUS (Size of cylinder radius) in units of grid cells [float]

Creating the run space

The Neutral PoreEstimate RPA 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 “Pore Confinement” 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. 87.

image 1

Figure 87: Setup window for the Neutral Pore Confine 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. 88.

Figure 88: 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.

Figure 89: Visualization of Neutral Pore Confinement as a color contour plot.

Further Experiments

Change the size of the blocks to see how different copolymer architectures are affected by confinement.

Change the radius of the cylinder ‘xs_CYLRADIUS’

Note, the image on the template thumbnail window is generated by running a 3D version of this example and then accessing the full VisIt capability by right clicking on the Visualization pane and starting the VisIt GUI.