writer：Ziqing Tang#, Feng Chen#, Qiang Chen* and Jie Zheng*, and et al.
keywords：Nanocomposite Hydrogels; Graphene Oxide; Mullins Effect; Self-recovery; Mechanical Properties.
source：期刊
specific source：Polymer Chemistry
Issue time：2017年

Nanocomposite

hydrogels (NC gels) are considered as one of high strength hydrogels. Graphene

oxide (GO), thanks to its amphiphilic, mechanical, optical property, is widely

used as fillers to incorporate into different hosting materials (elastomers, plastics,

and hydrogels) to improve their mechanical properties. In this work, we used in

situ free radical polymerization to synthesize polyacrylamide (PAAm)/GO

hybrid NC gels in the presence of GO nanosheets and a very small amount of

chemical crosslinkers (N, N''''-methylenebisacryamide, MBA<0.1

mol%). By optimizing GO and MBA concentrations, the resulting PAAm/GO gels can

achieve elastic modulus of 66 kPa, fracture stress of 0.27 MPa, fracture strain

of 13.76 mm/mm, deformed energy of 2.52 MJ/m3, and tearing energy of

964 J/m2. Due to the presence of physical interactions between PAAm

and GO nanosheets, PAAm/GO gels demonstrate λ-dependent

energy dissipation and Mullins self-recovery behaviors. The gels can rapidly

recover their stiffness and toughness by 76% and 60%, respectively after 30

min. resting at room temperature. The possible toughening mechanisms and

Mullins effect of PAAm/GO gels were proposed and compared with those of filler

rubbers and other high strength hydrogels. This work provides new viewpoints to

develop tough hydrogels by introduction of GO into other hydrogels with a good mechanical

balance between strong chemical bonding and reversible physical bonding.