Synthesis of PEGDMA. PEG polymers were first dried under vacuum at 70 °C overnight prior to the reaction. Take PEGDMA 6k as a representative example: PEG 6000 (60.0 g, 0.01 mol) was dissolved in 200 mL anhydrous DCM in a round bottom flask, followed by the addition of Et3N (4.2 mL, 0.03 mol).