Written‐in Conductive Patterns on Robust Graphene Oxide Biopaper by Electrochemical Microstamping

Multifunctional Pristine Chemically Modified Graphene Films as Strong as Stainless Steel

“…For comparison, GO films have also been prepared by filtration or evaporation of GO dispersions (denoted as f‐GO and e‐GO films, respectively). The mechanical performances of f‐GO (5) and e‐GO (5) films are much inferior to those of g‐GO (5) films (Figure e), although they are the highest among the GO‐based film materials reported previously (Figure f), and also much higher than the control films prepared from GO (35) sheets (synthesized via a conventional approach at an oxidation temperature of 35 °C; Figure S3, Supporting Information) . Post‐reduction of g‐GO (5) films resulted in the formation of g‐rGO (5) films with tensile strength of 614 ± 12 MPa, failure strain of 6.67 ± 0.44%, and toughness as high as 14.89 ± 1.02 MJ cm −3 , which are the highest values among the reported graphene‐based paper‐like materials (Figure f) .…”

“…This inherent chemical structure provides GO with rich physical and chemical cross‐linking sites for reinforcing the mechanical properties of CMG films via the interaction among GO sheets or between GO and external constituents . Extensive efforts have been devoted to increasing the interlayer interaction between GO sheets through hydrogen bonding, ionic binding, van de Waals attraction, and covalent cross‐linking, as well as the use of large sheets . Generally, ion binding and covalent crosslinking can remarkably improve the moduli and tensile strengths of CMG films, though at the expense of their toughness .…”

Silk Fibroin–Substrate Interactions at Heterogeneous Nanocomposite Interfaces

“…Addition of epoxide and carboxylic groups on the flake surface interfered with π‐stacking via interflake electrostatic repulsion which enabled facile solvation in aqueous media (Figure S5, Supporting Information). The flakes were amphiphilic, anionic particles as shown via contact angle and zeta potential measurements of 51° and −19.7 ± 0.9 mV, respectively …”

“…Of these methods, LbL assembly mimics the laminated design of nacre, thus enabling greater interfacial contact between the natural biopolymer matrix and synthetic filler component . This fabrication method enables silk to saturate interfacial interactions and dramatically enhance mechanical properties of these nanocomposites . Increased interfacial binding between silk fibroin materials and GO components facilitates higher Young's modulus and the ultimate stress.…”

“…To accomplish this task, we have fabricated ultrathin reconstituted silk fibroin‐GO laminates with GO at various levels of oxidation using spin assisted LbL assembly. We employ high resolution AFM and attenuated total reflectance Fourier Transform Infrared (ATR‐FTIR) spectroscopy to understand the binding behavior and morphologies that enable the exceptional performance of reconstituted silk fibroin‐GO nanocomposites previously reported . In addition, we performed MD simulations of the silk strands on graphitic surfaces to elucidate nonbonded interfacial interactions which govern the secondary structure of silk fibroin.…”