Macroporous Polyacrylamide Hydrogels With Tailored Porosity and Mechanical Properties via Microphase Separation in the Presence of Hydroxyethylcellulose

In this work hydroxyethylcellulose (HEC) was employed to prepare macroporous polyacrylamide (PAAm) hydrogels with different porosities and degrees of interconnectivity. The porosity and the equilibrium mass swelling ratio of hydrogels equilibrated in 0.1 M NaCl increased with the amount of HEC employed in the reaction mixture. Tensile and fracture tests were performed to investigate the mechanical behavior of both as prepared hydrogels and of hydrogels equilibrated in 0.1 M NaCl. As prepared hydrogels displayed invariably better mechanical properties than the corresponding equilibrated hydrogels. The mechanical stiffness decreased regularly as the amount of HEC (and porosity) was increased. A more complex trend was observed for the ultimate properties (elongation and stress at break) and for the fracture resistance, which displayed a maximum at intermediate HEC contents.