Dual Cross‐Linked Polymethacrylic Acid Hydrogels with Tunable Mechanical Properties and Shape Memory Behavior

Abstract

AbstractHerein, a series of poly(methacrylic acid) hydrogels are prepared via bulk polymerization of methacrylic acid (MAAc) and grafting of Triton X‐100 (TX‐100). One‐pot and extremely simple chemistry consist of only mixing and subsequently heating of commercially available monomer and surfactant. The polymer chains are interconnected through dual physical cross‐link points formed by the hydrophobic associations in the center of TX‐100 micelles and hydrogen bonds stabilized by hydrophobic α‐methyl groups of MAAc. The hydrogels exhibit tunable mechanical properties ranging between softness and stiffness by adjusting the surfactant/monomer molar ratio, such as Young modulus of 0.6−22 MPa, elongation at break of 750−1700%, tensile strength of 0.21−3.6 MPa, and compressive strength of 41−93 MPa. The synergistic effect of high‐density hydrogen bonds with hydrophobic associations endows a plastic‐like hydrogel with high strength and shape memory (SM) behavior, while a high concentration of micelles with low‐density hydrogen bonds endows a stretchable elastic hydrogel. The combination of temperature‐induced SM property and wide‐ranging mechanical performance will make such hydrogels useful in diverse applications.