Conventional epoxy resins and composites can attain G' values approaching and surpassing 10 9 Pa . Choosing this value as a benchmark for comparison, we formulated poly(GMA-co-PEGMA2000) copolymers at a 1:1 monomer ratio and 670 DP. The extremely long shielding group and long DP were chosen to provide a material that had both maximum latency and sensitivity to ultrasound. After sonicating these samples and leaving them to cure for 48 hours, the polymer crosslinked into an opaque white solid. Samples were prepared as 5x4 mm cylinders, and their moduli were assessed on a rheometer via compression with a 4 mm diameter plate. An elastic modulus value of 62 MPa was extracted from the resultant stress-strain curve (Figure ), approaching that of conventional epoxy materials. Immersing gels of this copolymer into acetone and ethanol showed no visible change in the material, but in MeCN, DCM, and water the gels crumbled into insoluble chunks (Figure ), leading us to conclude that the material's strength comes from a combination of epoxide-thiol covalent crosslinks and PEG side chain crystallization . Using a steric shielding approach, we created an ultrahard material through an unexpected combination of crystallinity and covalent bonding.