Nacre-Mimetic, Mechanically Flexible, and Electrically Conductive Silk Fibroin-MXene Composite Foams as Piezoresistive Pressure Sensors

Mohsen Bandar Abadi, Rene Weissing, Michael Wilhelm, Yan Demidov, Jaqueline Auer, Samaneh Ghazanfari, Babak Anasori, Sanjay Mathur, Hajar Maleki*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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The hierarchical nacre-like three-dimensional (3D) assembly of porous and lightweight materials is in high demand for applications such as sensors, flexible energy storage and harvesting devices, electromagnetic interference shielding, and biomedical applications. However, designing such a biomimetic hierarchical architecture is highly challenging due to the lack of experimental approaches to achieve the necessary control over the materials' microstructure on the multilength scale. Aerogels and foam-based materials have recently been developed as attractive candidates for pressure-sensing applications. However, despite recent progress, the bottleneck for these materials to achieve electrical conductivity combined with high mechanical flexibility and fast strain recovery remains. In this study, for the first time, inspired by the multiscale architecture of nacre, we fabricated a series of ultralightweight, flexible, electrically conductive, and relatively high-strength composite foams through hybridizing the cross-linked silk fibroin (SF) biopolymer, extracted from Bombyx mori silkworm cocoon, reinforced with two-dimensional graphene oxide (GO) and Ti3C2 MXene nanosheets. Nacre is a naturally porous material with a lightweight, mechanically robust network structure, thanks to its 3D interconnected lamella-bridge micromorphology. Inspired by this material, we assemble a cross-linked SF fibrous solution with MXene and GO nanosheets into nacre-like architecture using a bidirectional freeze-casting technique. Subsequent freeze-drying and gas-phase hydrophobization resulted in composite foams with 3D hierarchical porous architectures with a unique combination of mechanical resilience, electrical conductance, and ultra-lightness. The developed composite presented excellent performances as piezoresistive pressure-sensing devices and sorbents for oil/water separation, which indicated great potential in mechanically switchable electronics.

Original languageEnglish
Pages (from-to)34996–35007
Number of pages12
JournalACS Applied Materials & Interfaces
Issue number29
Publication statusPublished - 28 Jul 2021


  • MXene
  • bio-inspired foams
  • hybrid
  • nacre
  • piezoresistive wearable pressure sensor
  • silk fibroin


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