Figure shows the interdiffusion distances from Equations 4-6 fitted with a power function over welding time. Ungrafted linear polymers have the highest power exponent which then decreases with increasing grafting density. For comb-like (LC and DC) and bottlebrush (LB and DB) polymers, the exponents range from 0.26 ~ 0.27 and 0.11 ~ 0.12, respectively. The interdiffusion distance derived from Equation 3 is exhibited in Figure . Though bottlebrush polymers have more free ends with higher mobility, their penetration into other filaments is hindered by their increased gyration radius. In previous publications, the interfacial strength of linear polymers was reported to increase with welding time following an exponent of 1/4. However, in our simulations, the rupture strength scales with welding time as tw , slightly exceeding the exponent predicted in earlier works . This discrepancy likely stems from the shorter polymer chains used in our study compared to those in the referenced studies. Shorter polymers experience fewer topological constraints from entanglement, resulting in higher mobility. If branched polymers also rely on backbone entanglement, their interfacial strength of would reach the saturation more slowly compared to the linear polymers, because branched polymers diffuse slower than linear polymers. To evaluate this prediction, we compare the failure behaviors of branched polymers at welding time tw ranging from 10 4 τ to 10 5 in Figure . At tw = 10 4 τ, the linear, LC, and DC polymers demonstrate a lower rupture stress σmax and rupture strain εmax compared to bulk properties. However, the σmax of LB and DB reach the plateau at 10 4 τ, despite exhibiting lower rupture strain. At tw = 10 5 τ, the strain-stress curves of DC, LB, and DB are closely match their bulk properties, indicating complete fusion, while the linear and LC polymers remain incompletely fused, as evidenced by their inferior mechanical performance. In this scenario, our CGMD simulation results contradict the prediction, showing that branched polymers achieve interfacial strength saturation more rapidly than expected despite their slower diffusion. In Figure , the linear and LC polymers exhibit brittle rupture behavior. During the strain process, the stress ε climbs quickly and drops abruptly upon rupture. In contrast, a weak stress plateau emerges before fracture in the DC polymers. Meanwhile, the LB and DB polymers behave as elastomers, characterized by an increasingly prominent stress plateau. The transition to elastomers with increasing grafting density is attributed to the enhanced backbone rigidity, which can be quantified by the bond-bond correlation function, as described in Equation .