ecoSLM

This repository houses software and datasets (experimental and simulation) on the ecoSLM - a fast and approximate slip link model for predicting the linear viscoelasticity of blends of entangled star and linear polymers.

References

1. "Fast Slip Link Model for Bidisperse Linear Polymer Melts", Macromolecules, 2019, 52, 3092−3103 [doi: 10.1021/acs.macromol.8b02367].
2. "Mathematical foundations of an ultra coarse-grained slip link model", J. Chem. Phys., 2019, 151, 044903 [doi: 10.1063/1.5111032].
3. "Temporal Coarse-Graining in a Slip Link Model for Polydisperse Polymer Melts", Front. Phys., 2020, 8, 579499 [doi: 10.3389/fphy.2020.579499].

Code

Code files contain three Fortran 90 programs, which can be compiled as follows:

gfortran -O4 Utils1.f90 Initialize1.f90 -o ini gfortran -O4 Utils1.f90 Dynamics1.f90 -o dyna

The executable file ini can be used to initialize an ensemble, while dyna can be used to carry out dynamics.

The input file inp.dat is used to specify the simulation ensemble for a binary blend (star/linear, linear/linear, star/star).

Is fraction linear? [F if component is star, T if it is linear] 
F T
Number of chains, Np1, Np2 [# chains of component 1 and component 2; must be even, and Np1 cannot be zero]
2950 50
Number of SL, Z1, Z2 [avg #slip links on component 1 and 2]
8.0 116.1
Random number seed [random number seed for multiple replicas]
-3
ConstraintRelease [mark F if you want to suppress CR]
T

ini reads the input file, creates an ensemble, and equilibrates it by writing a snapshot file inSnap.dat.

dyna uses inp.dat and inSnap.dat and writes the final snapshot outSnap.dat and a file relax.dat. The latter file has three columns: the first column is the time, the second is the normalized stress and the last column is the normalized dielectric relaxation.

Expert Note:

In Dynamics1.f90, calibration for stars and linears is currently hard-coded for PBd at 25C. The following lines in the code may be suitably modified for any other situation.

gammaLin  = 1.4				
gammaStr  = 3.5

tau0Lin   = 0.12 
tau0Str   = 1.8e-3

Experimental Data

Contains three subfolders for linear-linear (LL), star-linear (SL), and star-star (SS)

Each subfolder contains folders corresponding to data from a particular source. The header file tags key features of the particular dataset including chemical species, temperature, citation to original paper containing the data, and some details of the systems such as molecular weights and weight fractions.