), but also reduced the elongation at break to 40% (Figures and). At 30 wt%, the objects became brittle similar to the PEGDMA 2k hydrogel, due to the higher ratio of short network units, with molar fraction of PEGDA 700 exceeding 80%. To further confirm the improvement of the mechanical properties brought by bimodal PEG networks, we compared the Young's modulus-polymer content relationships of the 3D printed products from different compositions, because it is known that the Young's modulus of hydrogels is highly dependent on the polymer content after swelling. As shown in Figure , the Et of the dual-macromonomer hydrogels as a function of crosslinked polymer content showed a strong positive correlation, with a slope higher than that obtained for singlemacromonomer hydrogels (prepared with BAPO-PEG or BAPO/NVP), which confirmed the improvement of the mechanical properties created by the bimodal network structure.