Amyloid fiber-induced gelation of liquid crystalline graphene oxide for robust and multifunctional films

초록

Liquid crystalline (LC) behavior of graphene oxide (GO) is critical for the development of high-performance materials. Gelation of LC GO suspension offers an efficient way to enhance interfacial interactions between GO sheets. However, polymeric gelators present a trade-off between enhancing interfacial interaction and preserving LC ordering. Herein, amyloid fibers (AFs), presenting diverse functional groups, are harnessed as a unique gelator for GO sheets to reinforce inter-sheet interactions without disruption of their LC phase. The optimized GO/AF film exhibits superior tensile strength of 259 f 22 MPa, modulus of 15.5 f 0.9 GPa, and toughness of 2217 f 247 kJ m-3 compared to pristine GO film, and those properties are further enhanced by Cu2+ ion cross-linking to 418 f 10 MPa, 30.8 f 2.3 GPa, and 5132 f 221 kJ m-3, respectively. Systematic characterization reveals that the Cu2+-GO/AF film exhibits multi-modal interactions through electrostatic, hydrogen, and coordination bonding. The synergistic toughening effect is estimated by synergy percentage analysis, and it is notably higher in the Cu2+-GO/AF film than in other reported GO composite films. The reduced Cu2+-GO/AF films exhibit high electrical conductivity, photothermal conversion, Joule heating, electromagnetic interference shielding, and thermoelectric output, making them promising as strong and multifunctional structural materials.

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