## 3 Results
### Effect of the Fraction of the Sacrificial Component, \(f_{v-\text{PDMS}}\)  
In the next series of simulations, we focus on the effect of the volume fraction of the sacrificial component, \(f_{v-\text{PDMS}}\), on the equilibrium morphology. We vary \(f_{v-\text{PDMS}}\) as following: [0.1, 0.2, 0.3, 0.4, 0.5]. Equilibrium snapshots of the systems with \(N_{v-\text{PDMS}}=60\) and the above values of \(f_{v-\text{PDMS}}\) are shown in Figure 4a. The corresponding snapshots of the sacrificial domains only are provided in Figure S4, where beads belonging to the distinct clusters are marked using the same color. These snapshots show that the sacrificial beads form large, interconnected clusters (Figure S4). A decrease in \(f_{v-\text{PDMS}}\) results in a clear shift of the \(g_{ss}(r)-1\) zero crossing towards higher values of \(r\) (Figure 4b), corresponding to the formation of larger sacrificial domains. Secondary shallow peaks in \(g_{ss}(r)\) are distinguishable at lower values of \(f_{v-\text{PDMS}}\) (inset in Figure 4b), indicating an average distance between the smaller domains. The characteristic average length scale in equilibrium, \(\overline{l}\)  
Figure 3: Effect of the degree of polymerization of the sacrificial component, \(N_{v-\text{PDMS}}\). **(a)** Equilibrium morphology snapshots of the blends with \(f_{v-\text{PDMS}}=0.5\) and various \(N_{v-\text{PDMS}}\). The values of \(N_{v-\text{PDMS}}\) from the left to the right are 10, 30, 60, 100, and 120. **(b)** The \(g_{ss}(r)-1\) at various \(N_{v-\text{PDMS}}\) as listed in the legend. **(c)** The average equilibrium characteristic length scale \(\overline{l}\). Here and below, \(\overline{l}\) is averaged over the data taken within the last five frames (upon reaching an equilibrium) for four independent simulation runs; the error bars correspond to the standard deviation. the average value of \(\overline{l}\) with an increase in \(N_{v-\text{PDMS}}\) (cases II, IV, and V) is found to be significantly more pronounced than a moderate increase in \(\overline{l}\) with an increase in \(N_{m-\text{PDMS}}\) (cases I-III). These trends are consistent with the trends observed in the binary systems (Figures 3c and 4c). Further, a direct comparison between the values of \(\overline{l}\) in cases III and V indicates that using longer reactive chains and shorter non-reactive sacrificial chains (\(N_{v-\text{PDMS}}=100\), \(N_{m-\text{PDMS}}=60\), case V) results in significantly more pronounced increase in the characteristic length scale \(\overline{l}\) than using longer non-reactive and shorter reactive chains (\(N_{v-\text{PDMS}}=60\), \(N_{m-\text{PDMS}}=100\), case III). The cases VI, II, and VII in Figure 5 illustrate the effect of the relative fraction of the non-reactive phase within the sacrificial component while keeping the degrees of polymerization of both sacrificial components the same \((N_{v-\text{PDMS}}=N_{m-\text{PDMS}}=60)\). Specifically, we chose \(f_{v-\text{PDMS}}=0.3\), \(0.4\), and \(0.5\) in cases VI, II, and VII, respectively. Recall that the total fraction of the sacrificial component is fixed in these simulations (\(f_{v-\text{PDMS}}+f_{m-\text{PDMS}}=0.5\)), so that the case VII corresponds to the binary system considered above and is provided in Figure 5 for comparison. These results quantify the decrease in the characteristic length scale \(\overline{l}\) with a relative increase in the fraction of the reactive sacrificial component, \(f_{v-\text{PDMS}}\). Finally, we probe the effect of the chemical nature of the non-reactive sacrificial component on the phase-separated morphology and the characteristic length scale within the system. In the final series of simulations, PAN and PMMA linear chains are used as non-reactive sacrificial components in addition to the \(v\)-PDMS reactive chains. In effect, these series of simulations correspond to the case II described in Figure 5, but with \(m\)-PDMS chains replaced with PAN or PMMA chains with the same number of beads.