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Fracture-resistant and ultrathin nanocardboard for structrual applications

Hollow, sandwich-like nanostructure that is joined by periodic, rigid webbing to increase bending stiffness and prevent fracture.

Technology Overview:

Mechanical metamaterials are increasingly used for structural applications. In particular, sandwich structures consisting of two planar face sheets connected by a webbing or foam core, can provide an optimal design for applications that require low weight and high-stiffness. Despite their utility, currently available sandwich plates are prone to fracture or permanent deformation when mechanically loaded and have not been scaled to the nanometer scale.

To overcome this issue, a new “nanocardboard” sandwich-like structure, has been invented. The nanocardboard is composed of two nanometer thick plates that are separated by a microscale gap and joined by rigid, periodic webbing. The meta-material is fabricated in a single step of atomic layer deposition of alumina on a silicon mold that contains the webbing.

The optimal webbing can be a honeycomb lattice, basket-weave pattern or cylinders packed in hexagonal packing. The final, optimized basketweave webbing structure is ultrathin, ultralight, has a high bending stiffness, and resists fracture and deformation when mechanically loaded. Furthermore, the material exhibits excellent thermal-insulating properties, making it well suited for high heat applications and electrical insulation.


  • Improved resilience to fracture and deformation during loading or shearing of the material
  • Single-step fabrication
  • Ultrathin and ultralight (~1 g m-2)
  • Excellent thermal and electrical insulator


  • Nano- and micro-electromechanical systems
  • Nanoscale thermal insulation
  • Biological membranes
  • Nanorobotics and microflyer wings
  • Scanning probe cantilevers
  • Interstellar lightsails

The nanocardboard structures are comprised of (A) two nanometer thick plates separated by a hollow microscale gap and joined by (B) periodic webbing that, in combination, allow the material to withstand fracture and deformation during mechanical loading and shearing. (C) A 13mm-diameter nanocardboard plate at macroscale.

Stage of Development:

  • Developed and tested in a laboratory environment
  • Demonstrated scale at 1 centimeter-square size

Intellectual Property:

US patent pending

Reference Media:

Nanocardboard as a nanoscale analog of hollow sandwich plates. Nature Communications 9, Article number: 4442 (2018).

Desired Partnerships:

  • License
  • Co-development 

Patent Information:


Docket # 18-8375

For Information, Contact:

Qishui Chen Licensing Officer, SEAS/SAS Licensing Group
University of Pennsylvania