High performing smart hyperbranched polyurethane nanocomposites with efficient self-healing, self-cleaning and photocatalytic attributes

The present work reports an in situ fabrication of hyperbranched polyurethane (HPU) nanocomposites with different weight percentages of reduced graphene oxide-silver-reduced carbon nanodot nano-hybrids as a nano-reinforcing material. The nanohybrid preparation was performed by a single one pot facile hydrothermal process. The nanohybrid and its nanocomposites were assessed by UV-visible, FTIR, XRD, EDX, TEM and thermal studies. The optical band gaps of the individual nanomaterials RCD (3.18), RGO (3.68 eV) and AgNPs (4.33 eV) were found to be significantly reduced in the nanohybrid (2.78 eV). The HPU nanocomposite degraded 96% aniline, 95% ethyl paraoxon organophosphate and 93% rhodamine B upon exposure to sunlight for 4 h, 2 h and 1 h 10 min, respectively. These degradations followed the pseudo-first order kinetics model. The nanocomposites exhibited major improvement in their performance in terms of elongation (1.17 fold), tensile strength (2.1 fold), scratch hardness (1.5 fold), toughness (2.9 fold) and thermal stability (22 degrees C). They displayed outstanding non-contact triggered shape-recovery upon exposure to microwaves (99.8%) and sunlight (99.6%) within just 20 s and 60 s, respectively. They also demonstrated efficient repeatable self-healing abilities under exposure to 20 s of microwave (99.7%) power input (360 W) and under direct exposure to sunlight (99.5%) (10(5) lux) for 4 min. Thus, the present work proposes this multifaceted nanocomposite with photocatalytic activity as a potential high performing self-healing and self-cleaning material.