High performance luminescent thermosetting waterborne hyperbranched polyurethane/carbon quantum dot nanocomposite with in vitro cytocompatibility

Development of high performance and benign polymeric material still remains a challenge across the globe. Comforting the prevailing challenge, we report in situ and ex situ fabrication of tannic acid based waterborne hyperbranched polyurethane (WPU) nanocomposites as fluorescent and cytocompatible materials by incorporating various weight percentages (0.5, 1.0 and 1.5 wt%) of carbon quantum dot (CQD). CQD was synthesized from corms of Colocasia esculenta having an average size 3.2 nm. The waterborne nanocomposites were cured by using glycerol based hyperbranched epoxy in the presence of fatty acid based poly(amido amine) to obtain the desired thermosets. FTIR, Raman, UV-visible spectroscopy, XRD study and HRTEM analyses confirmed the structural changes occurred upon interaction of CQD with WPU. The thermosets showed a good photo luminescent behavior, which confirmed efficiency of the polymer matrix to prevent solid state quenching. The thermosetting nanocomposites exhibited dose dependent improvement of mechanical (tensile strength ∼4.6 fold, toughness ∼4.2 fold, scratch hardness> 2 fold, impact resistance> 1.25 fold compared to thermoplastic pristine WPU) and thermal stability (maximum 28 °C enhancement). The thermosetting films were found to be biocompatible for in vitro adhesion, proliferation and differentiation of MG 63 osteoblast cells with good cell viability.