Bio-derived aliphatic hyperbranched polyurethane nanocomposites with inherent self healing tendency and surface hydrophobicity: Towards creating high performance smart materials

Smart materials with high performance are useful for multi-dimensional utilities. In this context, bio-resource derived aliphatic hyperbranched polyurethane nanocomposites (HPU/Si-GO) were fabricated in situ with different wt% of the 3-aminopropyltriethoxysilane-modified graphene oxide sheets (Si-GO). The nanocomposites were characterized by FT-IR, Raman, PXRD, EDX, SEM and TEM analyses. Significant enhancements of mechanical properties like tensile strength (∼247%), elongation at break (∼206%) and toughness (∼339%) were observed upon incorporation of very low amount (up to 2 wt%) of Si-GO in HPU matrix. The nanocomposites exhibited excellent self healing ability under microwave (within 50-60 s at 450 W) and sunlight (within 4-6 min under 106 lx) exposure with high efficiency (up to 100%). The surfaces of the nanocomposites also displayed inherent hydrophobicity (water contact angles up to 105°) without any additional surface modification. Hence, development of such high performance polymeric materials with inherent smart features augurs well for versatile applications including self healing and self cleaning materials.