Determine whether PEGDA network strands form polymer blobs

Determine whether the polymer chains between crosslinks in poly(ethylene glycol) diacrylate hydrogels are sufficiently long to form polymer blobs, as assumed by classical semidilute-polymer-solution scaling theories.

Background

The paper compares measured transport-property scalings for PEGDA hydrogels with classical predictions based on an idealized, homogeneous, semidilute polymer network. Those predictions treat the hydrogel as a polymer solution whose chains form necklace-like blobs, with blob size controlling permeability and osmotic pressure.

The PEGDA hydrogels studied here are synthesized from relatively short oligomers containing approximately 13 monomer units and are capped with hydrophobic acrylate groups. Because the chain length between crosslinks may be insufficient for blob formation, the applicability of the classical scaling assumptions to these real hydrogels remains unresolved. Resolving this issue would help explain why the measured permeability, effective pressure, bulk modulus, and poroelastic diffusivity depend on polymer volume fraction differently from the classical predictions.