Vertical and uniform growth of MoS2 nanosheets on GO nanosheets for efficient mechanical reinforcement in polymer scaffold

Graphene oxide (GO) and molybdenum disulphide (MoS2), have drawn more and more attention as reinforcement in polymer. However, their large specific surface area and strong van der Waals forces result in serious aggregations in polymer matrix, which restrains the reinforcement effect. In this study, MoS2 nanosheets were in situ synthesised vertically and uniformly on the surface of GO nanosheets with the help of a hexadecyl trimethyl ammonium bromide (CTAB) assisted hydrothermal process to facilitate their dispersion in polylactic acid (PLLA) scaffold manufactured via selective laser sintering (SLS). The experimental results revealed that the 1.5 wt% GO/MoS2 nanocomposite exhibited better dispersion state compared with the 1.5 wt% GO and 1.5 wt% MoS2 in PLLA matrix. Therefore, the PLLA scaffold loading 1.5 wt% GO/MoS2 presented 10.2 and 1461 MPa of tensile strength and modulus with enhancement of 61% and 58%, respectively, compared with the pure PLLA scaffold. The reinforcement mechanisms mainly included crack deflection, crack bridging, crack pinning and pulling out of GO/MoS2. What's more, the GO/MoS2-PLLA scaffold possessed benign cytocompatibility for cell behaviour, suggesting hopeful applications in bone defect repair.