Robust and Self‐Healing Hydrophobic Association Hydrogels Using Poly(styrene‐co‐acrylonitrile) Macromolecule Microspheres as Cross‐Linking Centers

In our strategy, polystyrene (PS) and poly(styrene‐acrylonitrile) (P(S‐AN)) macromolecular microspheres (MMs) were introduced within hydrophobically associated (HA) hydrogels to enhance their mechanical strength. Two series of MMs hydrophobically associated polyacrylamide composite hydrogels (MMHA gels) were fabricated by a simple one‐pot method. The mechanical, rheological and swelling properties of MMHA gels were investigated and also evaluated as a function of the content of MMs. The mechanical properties of MMHA gels exhibit a tendency to increase first and then decrease with the increase in MMs content. In addition, the structure of the MMHA hydrogels was investigated by the IR and SEM analysis. The results were consistent with the result of mechanical, self‐healing and swelling properties test. Impressively, compared with MMHA gels enhanced by PS MMs (SHA gels), MMHA gels enhanced by P(S‐AN) MMs (SNHA gels) showed better mechanical properties(tensile strength 550 KPa, elongation at break 2832%)due to the strong dipole‐dipole interactions of ‐CN groups from acrylonitrile. Furthermore, the oil/water separation capability of the SNHA gels was explored preliminarily. Our strategy shows a novel direction for the production of tough hydrogels with various potential applications. In this paper, PS and P(S‐AN) macromolecule microspheres(MMs) were synthetized by emulsion polymerization method. When reactive monomers and MMs were mixed, the hydrophobic monomer(SMA) would be adsorbed on MMs through hydrophobic interactions, and then polymerized on them initiated thermally by KPS. Finally, the physically cross‐linked MMHA hydrogel network was constructed. The obtained hydrogels could afford tremendous force due to efficient aggregation of hydrophobic chains and MMs in the hydrogel system.