Researchers from the University of Vienna and Technical University of Vienna have used a unique technique to significantly enhance the stretchability of graphene for the first time by creating an accordion-like ripple effect. This achievement could open up new possibilities for applications that require specific levels of stretchability, such as wearable electronics.
Graphene is notable for its high electrical conductivity but tends to be extremely stiff, as its atoms are arranged in a honeycomb pattern that contributes to this stiffness. It makes sense that removing some atoms from the material along with their bonds would result in reduced stiffness. Scientific research, however, has documented both a modest decline and a notable rise. Scientists have now resolved these contradictions with new measurements. Modern devices were used in the experiments and housed in the same ultra-clean, airless environment. As a result, samples can be moved between the various devices without contacting outside air.
“This unique system we have developed in the University of Vienna allows us to examine 2D materials without interference,” explained University of Vienna's Jani Kotakoski.
The accordion effect, which affects graphene's stiffness, was discovered due to the emphasis on meticulous surface cleanliness: removing two nearby atoms causes the initially flat material to bulge noticeably. When multiple bulges are combined, the material becomes corrugated.
Wave formation and the resulting stretchability were confirmed by simulations conducted by Vienna University of Technology Theoretical Physicists Rika Saskia Windisch and Florian Libisch. The experiments also demonstrated that foreign particles on the material surface cause the opposite effect, in addition to suppressing it. In particular, their influence gives the impression that the material is stiffer, which also explains historical contradictions.
This work stresses the importance of the measurement environment when dealing with 2D materials and its results could open up a way to regulate the stiffness of graphene and thus pave the way for potential applications.
