Hello LAMMPS users,
I am interested in the cohesive energy between the polymer chains and later use it to determine the Hildebrand solubility parameters as given below.
Solubility = sqrt ( E_coh / Volume)
E_coh = summation (E_iso) - E_tot; E_iso is the potential energy of each chain in the system and E_tot is the energy.
Here are list of things I did:
Method-1) Generate an equilibrated polymer box with 5 chains. Use the last frame to determine the potential energy (run 0), which would be E_tot
Later, I have created 5 independent datafiles, for each polymer chain, using exact polymer configuration and simulation box to determined energy of the polymer chain (E_iso). I have determined E_coh as mentioned above.
Of course, this procedure is not ideal when there are several chains and several frames to determined the solubility parameter.
Method-2) To determine the solubility parameter, on the fly, while the simulation is running.
In the same example, I have defined five groups and determined as shown below.