Forming CNT-guided stereocomplex networks in polylactide-based nanocomposites

Grafting a nanoparticle surface using a polymer similar to the matrix has been widely applied to control the spatial organization of nanoparticles. However, the fabrication of target materials with well-defined nanoparticle arrangement remains fundamentally difficult because of the absence of specific interactions between the matrix and the graft. In this study, the self-networking structure of poly(d-lactide)-grafted carbon nanotubes (CNT-g-PDLA) in poly(l-lactide) (PLLA) matrix was investigated. Specific interactions between enantiomeric pairs not only promoted CNT dispersion, but also contributed to the regular phase-separation-like CNT self-networking. Furthermore, the grafted PDLA chains preferably formed stable stereocomplex crystallites with the PLLA matrix, and the CNT self-networking resulted in the self-assembly of 3D continuous stereocomplex scaffold. It was demonstrated that the CNT-guided stereocomplex network endows polylactide-based nanocomposites with significantly improved mechanical strength, heat-resistance, and electrical conductivity at low CNT concentrations.