2D Ni-Fe MOF nanosheets reinforced poly(vinyl alcohol) hydrogels with enhanced mechanical and tribological performance

The crucial challenge of 2D inorganic nanomaterials-filled composite hydrogel with outstanding mechanical properties was concentrated on the surface modification that was capable to access a better interface between 2D inorganic nanomaterials and hydrogel in past. In this paper, for the first time, we extensively studied the application of as-synthesized 2D Ni-Fe MOF nanosheets with natural organic interface and interlayer structure in PVA hydrogel. The morphology and structure of the as-prepared 2D Ni-Fe MOF/PVA composite hydrogels were determined by a series of characterizations. The results indicated that the as-prepared 2D Ni-Fe MOF/PVA composite hydrogel with porous structure exhibited a desirable dispersion due to the existence of the potential interfacial interaction. Furthermore, the swelling, mechanical and tribological properties of the composite hydrogel were intensively investigated. Dramatically, the tensile strength and compression modulus of the as-prepared 2D Ni-Fe MOF/PVA with 0.1 wt.% filling content were increased by 62.5 % and 113 % relative to pure PVA hydrogel, respectively. Owing to the presence of the interlayer structure of 2D Ni-Fe MOF nanosheets, the friction coefficient of the 2D Ni-Fe/PVA composite hydrogel with 0.15 wt.% filling content was reduced by 41 % compared to pure PVA hydrogel.