Nanomechanics of graphene oxide-bacteriophage based self-assembled porous composites

Yiwei Sun,Pola Goldberg Oppenheimer,Paolo Passaretti,Jesus Gonzalez,Colin J Humphreys,Wei Liu,Fernando Rodriguez,Ignacio Hernandez,David J Dunstan

doi:10.1038/s41598-020-72372-1

Abstract

Graphene oxide, integrated with the filamentous bacteriophage M13, forms a 3D large-scale multifunctional porous structure by self-assembly, with considerable potential for applications. We performed Raman spectroscopy under pressure on this porous composite to understand its fundamental mechanics. The results show that at low applied pressure, the sp^2 bonds of graphene oxide stiffen very little with increasing pressure, suggesting a complicated behaviour of water intercalated between the graphene layers. The key message of this paper is that water in a confined space can have a significant impact on the nanostructure that hosts it. We introduced carbon nanotubes during the self-assembly of graphene oxide and M13, and a similar porous macro-structure was observed. However, in the presence of carbon nanotubes, pressure is transmitted to the sp^2 bonds of graphene oxide straightforwardly as in graphite. The electrical conductivity of the composite containing carbon nanotubes is improved by about 30 times at a bias voltage of 10 V. This observation suggests that the porous structure has potential in applications where good electrical conductivity is desired, such as sensors and batteries.

Highlights

Graphene oxide, integrated with the filamentous bacteriophage M13, forms a 3D large-scale multifunctional porous structure by self-assembly, with considerable potential for applications
Graphene oxide (GO)-based structures would be more appealing for applications like sensors, catalysts, energy conversion, batteries and supercapacitors, where this porous structure could be employed if its electrical conductivity can be improved[3]
By studying the evolution of the Raman peaks over the G-mode range with pressure, we find that in the GO the G-mode shifts very little with pressure up to 0.8 GPa, and increases at a similar rate to graphite before a structural change is observed at 5.7 GPa

Summary

Introduction

Graphene oxide, integrated with the filamentous bacteriophage M13, forms a 3D large-scale multifunctional porous structure by self-assembly, with considerable potential for applications. The shift rate recovers to the graphite level in the range of about 1.0 to 3.6 GPa. There is no abrupt change of the width of the G and D ′ modes and of the intensity ratio between these two up to 3.6 GPa. The spectrum at 5.7 GPa evolves differently from the previous spectra obtained at lower pressures.

Results

Conclusion