## 3 Results and Discussion
### Replication Capability of Nanostructures  
In order to analyze the replication capability of nanostructures, the filling rate is introduced; that is, the ratio of the polymer density in the nanocavity to the initial set density of the PC system. It can be seen from Figure 6 that the filling rate of the short-chain polymer system rises sharply during the packing stage and tends to balance rapidly, with the filling rate exceeding 95%. This further indicates that the short-chain polymer can easily overcome resistance under the action of pressure and fill the cavity quickly, with a high filling rate and good replication capability.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**E**} & \multicolumn{4}{c}{**CIM**} & \multicolumn{4}{c}{**RHCM**} \\ \cline{2-10}  & **PC/Ni** & **PC** & **Ni** & **Einter** & **PC/Ni** & **PC** & **Ni** & **Einter** \\ \hline E\({}_{\text{total}}\) & \(-\)1,801,355 & 7602 & \(-\)1,808,100 & \(-\)857 & \(-\)1,775,840 & 19,366 & \(-\)1,794,160 & \(-\)1046  
Under different molding conditions, the filling rate of the long-chain PC in the nanostructures fluctuates greatly. Moreover, the filling rate grows slowly in CIM, which shows that the polymer cools quickly during the filling process at a low temperature of the mold and molecular chain motion ability is low. Therefore, the filling effect is poor with low replication capability. Under the RHCM process, the filling rate grows rapidly, but the difference is obvious at the pressure of 40 MPa and 80 MPa. In order to more intuitively analyze the replication capability of nanostructures under different pressures, it can be further characterized by its molding morphology [26]. Figure 7 shows the filling morphological evolution process of the polymer in the nanostructures at different pressures during the packing stage, which can directly reflect the filling situation of the polymer in the nanocavity. PC molecular chains are driven by pressure to overcome the entanglement resistance and fill the cavity. Especially at a pressure of 80 MPa, the long molecular chains are closely arranged and there is almost no void in the cavity. Furthermore, the filling rate reaches 94%, with a good replication capability of nanostructures. Although the long molecular chains have filled the cavity at a pressure of 40 MPa, there are still obvious voids between the molecular chains and the filling rate can only reach 70%. This shows that the packing pressure plays an important role in filling the nanostructures and is the main driving force of filling the nanostructures. The high packing pressure can obviously improve the filling effect of the nanostructures, improving the molding replication capability of the products. It is worth noting that the morphological evolution of the filling process of the short-chains at a pressure of 40 MPa is faster than that of the long-chains, which further indicates that the short-chains overcome more easily the viscous resistance due to their lower viscosity, and the filling effect is better.  
Figure 7: The filling morphological evolution of polymers in the nanostructures at different pressures during the packing stage.