University of Pittsburgh researchers have produced, using a unique fabrication process, macroscale carbon fiber found to be stronger than existing similar materials such as graphene or carbon nanotubes. This material can be grown by chemical vapor deposition and has the potential to form the next generation of lightweight, flexible, malleable, high-strength materials.
Description
Since its discovery, researchers have investigated the impressive mechanical properties of graphene, one of the strongest materials in the world. In the nanoscale, it is many times stronger than steel, incredibly lightweight and flexible, with huge potential uses in many markets. However, mechanical strength on the macroscale is three orders of magnitude lower in the nanoscale. Current macroscale uses of carbon fibers, including graphene and graphene oxides, are as composite materials. Non-composite macroscale graphene fiber has applications in a diverse range of industries, including biomedicine and, electronics. Yet, these applications are not readily available.
Applications
- Semiconductor industry
- Composite materials
- Sensor development
- Aerospace engineering, including outdoor coatings and composites
Advantages
Graphene, a honeycomb sheet of carbon atoms, is the world’s strongest material, yet with incredible elasticity and conductive properties. Its discovery resulted in the 2010 Nobel Prize in Physics. Utilization of graphene could lead to technological advancements in many fields. Nanoscale graphene is extremely elastic, (E=1.02 TPa) and has intrinsic strength (σint=130 GPa). However, on a macroscale, tensile strength drops dramatically to 1.45 GPa. This discrepancy in strength is a consequence of defects and flaws related to interlayer coupling and graphene layer alignment. This novel fabrication is unique in that it can produce strong carbon fibers at a macroscale without the use of organic polymers or other supporting materials.
Invention Readiness
Fibers were fabricated by physically folding a single sheet of single-layer CVD-grown graphene into a one-dimensional wire. These fibers were 0.1–2 cm in length. Testing discovered two distinct failure patterns near the maximum load, sudden breaking of the fiber (brittle) and a fracture propagating across the width of the graphene (ductile). The average breaking strength of ductile fibers was 1.75 GPa (0.62 GPa). These fibres set a record for mechanical strength of macroscale graphene fibers (breaking strength = 2.67 GPa at a 1 mm gauge length). Understanding the mechanisms behind this increased strength could allow for the development of stronger and more advanced materials.
IP Status
https://patents.google.com/patent/WO2021158733A1
