Facile Fabrication of Tough Super Macroporous Hydrogel via Enhanced Phase Separation

Super macroporous (SMP) hydrogels have garnered significant attention in biomedical applications due to their high permeability and biomimetic pore structure. However, maintaining toughness in highly porous materials remains a formidable challenge. This study introduces a facile one-step preparation method for fabricating tough alginate hydrogels with an SMP structure by blending polyvinyl alcohol (PVA) and sodium alginate cross-linked with calcium chloride. By capitalizing on the phase separation effect, this method bypasses traditional requirements such as cryogelation and templating that necessitate low temperatures or solvent etching. The presence of PVA molecules promotes the regional aggregation of alginates, leading to enhanced toughness, and also occupies larger interstitial spaces between the densely packed alginate phases, facilitating pore formation. The resulting SMP structure, featuring pore sizes ranging from 50 µm to 700 µm, forms during the polymer cross-linking process and achieves a porosity exceeding 85%. These hydrogels exhibit superior toughness compare to their non-macroporous counterparts. Additionally, this method allows for flexible adjustments in the porous structure and overall gel shape, making it adaptable to various applications. This simple yet effective approach holds great potential for developing novel SMP materials with enhanced toughness.