Mussel-inspired, robust and self-healing nanocomposite hydrogels: Effective reusable absorbents for removal both anionic and cationic dyes

Polydopamine (PDA) composited LAPONITE® cross-linked hydrophobically associated (PLHA) hydrogels were facilely constructed by in situ polymerization. The PLHA hydrogel exerted improved mechanical properties and excellent stability with an additional cross-linking agent LAPONITE®, which guaranteed the hydrogel could be utilized for long-time and reusable application. Notably, the self-healing property of PLHA gels could be achieved easily by the hereinafter three factors: hydrophobic association, LAPONITE® and PDA. Compared with the pristine hydrophobic associated (HA) gel, excellent dye adsorption capacity towards both anionic and cationic dyes came out in PLHA gels owing to the negative charges on LAPONITE and abundant functional groups on PDA nanoparticles such as amine groups, catechol groups and aromatic moieties. The PLHA gels could bind organic dyes via various ways, including coordination, electrostatic interaction, hydrogen bonding or π-π stacking interaction. Compared with the reported works, our proposed method provided the opportunity to prepare a novel robust, self-healing physically dual cross-linked hydrogels, which have the potential to be applied in tissue engineering and the reusable adsorbents of organic colorants.