Biopolymeric Nanocomposites with Enhanced Interphases
- Publication date
- 2015
- Publisher
Abstract
Ultrathin and robust nanocomposite
membranes were fabricated by
incorporating graphene oxide (GO) sheets into a silk fibroin (SF)
matrix by a dynamic spin-assisted layer-by-layer assembly (dSA-LbL).
We observed that in contrast to traditional SA-LbL reported earlier
fast solution removal during dropping of solution on constantly spinning
substrates resulted in largely unfolded biomacromolecules with enhanced
surface interactions and suppressed nanofibril formation. The resulting
laminated nanocomposites possess outstanding mechanical properties,
significantly exceeding those previously reported for conventional
LbL films with similar composition. The tensile modulus reached extremely
high values of 170 GPa, which have never been reported for graphene
oxide-based nanocomposites, the ultimate strength was close to 300
MPa, and the toughness was above 3.4 MJ m<sup>–3</sup>. The
failure modes observed for these membranes suggested the self-reinforcing
mechanism of adjacent graphene oxide sheets with strong 2 nm thick
silk interphase composed mostly from individual backbones. This interphase
reinforcement leads to the effective load transfer between the graphene
oxide components in reinforced laminated nanocomposite materials with
excellent mechanical strength that surpasses those known today for
conventional flexible laminated carbon nanocomposites from graphene
oxide and biopolymer components