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 (similar to 247%), elongation at break (similar to 206%) and toughness (similar to 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 sat 450 W) and sunlight (within 4-6 min under 10(6) lx) exposure with high efficiency (up to 100%). The surfaces of the nanocomposites also displayed inherent hydrophobicity (water contact angles up to 105 degrees) 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.