Simulation and the model
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The simulations, in the $(N,V,T)$ ensemble, were performed using the ${\rm ESPResSo}$ package [@Limbach2006704]. The length scale in our simulation is the diameter of each monomer, $\sigma$, and we scale the energies based on the Lennard-Jones (LJ) energy $\epsilon$. We consider the Lennard-Jones time scales as a measurement unit for the time $\tau=\sigma \sqrt{m/\epsilon}$, where $m$ is set to unity for all the monomers. We used the Langevin thermostat with damping constant $\gamma=\frac{1}{2}\tau^{-1}$ to keep the equilibrium temperature of the system around $T=\epsilon/k_{\mathrm B}$. The velocity Verlet algorithm was used with time step of $t=0.001\tau$ during the equilibrating stage, and $t=0.01\tau$ for production run. Here we considered $\sigma=1$, $\epsilon =1 (k_{\mathrm B}T)$, and temperature is $T=1$.

We construct the polymer chains as bead-spring model which is confined in a large spherical container with impenetrable wall, Fig. \[fig:seg\_poly\](b). For each chain, we use the prefix [*intra*]{} for anything related to the united monomers in each segment, and [*inter*]{} where it indicates between the segments of the same chain. To mimic the excluded-volume effect, a purely repulsive Lennard-Jones potential is applied to the bead-bead and bead-wall (container) interactions, $V_{\rm LJ}\left(r\right)=4\epsilon \left[ \left( \sigma/r\right)^{12} -\left( \sigma/r\right)^{6} +1/4 \right] 