Composite material from Penn State University has tunable electric properties due to bioengineered tandem repeat proteins.

Benefits

  • Flexible
  • Conductive
  • Controllable

Applications

  • Electronic devices

UN Sustainable Development Goals Addressed

  • Goal 9: Industry Innovation & Infrastructure

The Challenge

Composite materials have limited physical properties due to the physical limits of the components and interactions between them. The ‘rule of mixtures’ is a prediction theory that states that while the matrix-to-filler ratios of one component to another can vary in a mixture, there is a limit to the physical properties (elastic modulus, tensile strength, etc.) of the composite. This has prevented material scientists from creating mixtures with tunable properties.

 

Innovation Details

The composite material is made of a synthetic tandem repeat inspired by the structure of squid ring teeth proteins, and a very thin metal known as titanium carbide 2D MXene. The composite self-assembles into a cross-linked network, which changes the electrical properties of the layered material and causes the matrix-to-filler ratios in tiny areas to ‘break’ the mixture rules. On the microscopic scale, when the structural symmetry is broken, electrical conductivity depends on direction. As long as the current is going along the plane of the 2D material layers, the conductivity is linear, but if the current is directed across the layers, the conductivity becomes nonlinear. This allows the researchers to make different types of electronic devices, such as storage devices, diodes, switches, or regulators. The researchers can control the distance between conducting layers without changing the composite fraction by controlling the length of the tandem repeat proteins, which they have bioengineered.

Biomimicry Story

Squid have teeth in ring formations inside suction cups on their tentacles. The squid ring teeth are made up of proteins that can combine in different ways to produce materials with different properties. These teeth help the squid grip onto a surface or grasp prey. If the teeth break, they can self-heal.