Table 1.
Storage modulus of hydrogels after the Michael addition reaction (20 minutes), peak storage modulus after initial UV exposure (365 nm, 5 mW/cm2), and the final storage modulus of the hydrogel after 10 minutes of UV exposure with four‐arm PEG‐maleimide and 2 kDa PEG‐dithiol (5 wt% total macromer) using varied photoinitiator (LAP) concentrations and thiol:maleimide ratios.
| wt.% LAP | SH:Mal | Radicals: Crosslinks | Pre‐UV Modulus a) [Pa] | Peak Modulus a) [Pa] | Post‐UV Modulus a ) [Pa] |
|---|---|---|---|---|---|
| 0 | 1:1 | 0 | 456 ± 50 | ‐ | 460 ± 40 |
| 0.3 | 1:1 | 1.1 | 470 ± 70 | 800 ± 100 | 250 ± 40 |
| 0.5 | 1:1 | 1.9 | 500 ± 70 | 780 ± 70 | 16 ± 10 |
| 1.0 | 1:1 | 3.8 | 521 ± 40 | 700 ± 120 | ‐ |
| 0.5 | 2:1 | 1.9 | 180 ± 20 | 180 ± 20 | ‐ |
| 0.5 | 1:2 | 1.9 | 210 ± 60 | 540 ± 160 | 32 ± 5 |
a)
Measured using oscillatory shear at 1 rad/s, 1% strain.