a You are designing a soft hydrogel for wound healing applications. You polymerize a 15kDa PEG dimethacrylate in the bulk (no solvent present) using a free radical initiator. Post-gelation, you swell the hydrogel in water. At equilibrium, you measure that your mass swell ratio is 150. 2.1 What is your number average molecular weight between crosslinks? 2.2 What is the weight fraction of your network in the swollen state? 2.3 How much tensile stress do you need to apply to stretch your hydrogel by 50% (50% elongation)