To address this, we perform additional point charge optimization using two distinct methods: Charge equilibration (Qeq) method and density-functional-theory calculations. The Moltemplate software is used to generate the topology and parameters for the universal force-fields, i.e., OPLS-AA, COMPASS and Dreiding, while the Huang's and united-atom models are created manually with parameters extracted from the original paper. In detail, a uniform cut-off distance of 1 nm is applied to COMPASS, UA, and dreiding (HUANG model uses 1.2 and OPLS uses 1.1) for non-bonded interactions. This same distance is also used as the switching distance in the Particle-Particle Particle-Mesh (PPPM) algorithm for calculating long-range Coulomb interactions in the all-atom models. More details about the force-field parameters are available in the Supporting Information. All simulations are performed using the LAMMPS (Large-Scale Atomic/Molecular Massively Parallel Simulator) package with periodic boundary conditions applied in the x, y, and z directions. The initial configurations of the systems are created using the Packmol, where polymer chains are randomly placed in a large cubic box. The details of the simulated systems are given in Table . The simulation workflow consists of three main stages: system generation, equilibration, and production. In the generation stage, the initial configuration is set at T = 300 K and P = 100 atm under the NPT ensemble. The high pressure in this step is used to force the chains into the liquid phase. The pressure is then gradually reduced to P = 1 atm, and the system is allowed to pre-equilibrate at this pressure until the density converged. This is followed by a 1 ns equilibration phase under the NPT ensemble at T = 300 K and P = 1 atm. Equilibration is monitored by observing the fluctuation of the total energy within a small variation. After equilibration, production runs are conducted to gather data for property calculations. It is noted that, for computing viscosity, the system is considered equilibrated when the autocorrelation function of chain end-to-end vector decays to zero. Three distinct types of production runs are employed, each designed to calculate particular properties, as detailed in the following sections. It is important to note that due to the varying relaxation times of the system at different temperatures, the durations of the production runs can differ. The Nóse-Hoover thermostat and barostat are employed with coupling constants of τ P = 1 ps and τ T = 0.1 ps, respectively. The equations of motion are integrated using the Velocity-Verlet algorithm with a time step of δt = 1 fs for all models. Additional details on the simulation setup can be found in Supporting Information.