How to maintain a clear interface between two different kinds of polymers during NPT, NVT for calculation of interfacial thermal resistance

Hi, I am calculating the interfacial thermal resistance between two different kinds of polymers. I’m facing issues regarding creating a clear interface between them during densification and equilibration using NPT, NVT ensembles. I packed them like polymer A, polymer B, polymer A. in 3PBC box.

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I need script guidance for LAMMPS, molecular dynamics. I am using freeze atoms command in some part of the between the two polymers. Sometimes worked sometimes not. Need guidance.

What is a clear interface?

What you are asking resembles something you should discuss with your advisor rather than here.

Hi Muhammad,

Thank you for starting a new thread as requested.

As I advised in my earlier post:

Additionally, do make your questions more clear and concrete. “How did you do XYZ?” is often very difficult for us to answer clearly because we do not know what you have or haven’t tried and therefore what advice we should give.

The easiest questions for us to answer are: “I thought that doing ABC would give results X, based on my understanding of P physical / mathematical principle / statement from the documentation, but I got results Y instead, and I would like to know why.”

In this case, I can see that you “have trouble maintaining a clear interface”, but it is not clear to me:

  • Why you expect a clear interface to be maintained (maybe the polymers genuinely “want” to mix)
  • Which phase of the simulation you need the interface to be maintained during (during npt? Nvt?)

If you are able to justify that a particular thing should happen (ideally by citing a prior study that you have tried to replicate) then it is easier to troubleshoot.