Biodegradable\nPorous Poly(ε-caprolactone)s:\nEmulsion Templating Stabilization and Ring-Opening Cross-linking

PolyMIPEs are emulsion-templated macroporous polymers\nsynthesized\nwithin medium internal phase emulsions (MIPEs), emulsions with dispersed\nphases between 40 and 74 vol %. Here, biodegradable poly(ε-caprolactone)\n(PCL) polyMIPEs, synthesized using ring-opening polymerization within\noil-in-oil MIPEs, were cross-linked with either a novel combination\nof pentaerythritol (initiator) and glutaraldehyde (star cross-linker)\nor with bis(ε-caprolactone-4-yl). PolyMIPEs from emulsions stabilized\nusing a surfactant, nanoparticles (NPs), or innovative polymer brushes\n(PBs) with predesigned arms were compared. The polyMIPEs exhibited\nmoduli similar to those of soft tissues, withstood compressive strains\nup to 70%, and underwent complete hydrolytic degradation. PolyMIPEs\nfrom NP-stabilized MIPEs exhibited closed-cell structures with relatively\nlarge voids and lower moduli, while polyMIPEs from PB-stabilized MIPEs\nexhibited significantly smaller voids and higher moduli, revealing\nan unexpected connection between the void diameters and the mechanical\nproperties. This work lays the foundation for modifying the macromolecular\nstructures, porous structures, and properties of macroporous PCL monoliths\nthrough the cross-linking and emulsion-stabilization strategies.