Strong fatigue-resistant nanofibrous hydrogels inspired by lobster underbelly

Abstract

•Hierarchical assembly of welded and high-crystalline bouligand structure in hydrogels •Mechanics-guided design of high fatigue resistance for nanofibrous hydrogels •Fatigue characterization of nanofibers in synthetic hydrogels •High-velocity microparticle impacts on synthetic nanofibrous hydrogels Nanofibrous hydrogels are pervasive in animal and plant bodies and have been widely seen in engineering applications. Electrospinning is one of the most widely used methods for the fabrication of nanofibrous hydrogels. Whereas the biological nanofibrous hydrogels can maintain high strength and high toughness under multiple cycles of mechanical loads, such fatigue-resistant properties have not been achieved in electrospun nanofibrous hydrogels. Here, we report a bioinspired design of strong and fatigue-resistant nanofibrous hydrogels that can closely mimic the bouligand structure of the natural hydrogel in the lobster underbelly. The resultant nanofibrous hydrogel can reach high nominal strength up to 8.4 MPa and high fatigue threshold up to 770 J/m2. We further demonstrate the superior impact resistance of the bioinspired bouligand-type nanofibrous hydrogel with specific penetration energy of 40 kJ/kg. We show that it is critical to weld the interfaces between nanofibers and introduce intrinsically high-energy phases (nanocrystalline domains) into nanofibers. Nanofibrous hydrogels are pervasive in animal and plant bodies and have been widely seen in engineering applications. Electrospinning is one of the most widely used methods for the fabrication of nanofibrous hydrogels. Whereas the biological nanofibrous hydrogels can maintain high strength and high toughness under multiple cycles of mechanical loads, such fatigue-resistant properties have not been achieved in electrospun nanofibrous hydrogels. Here, we report a bioinspired design of strong and fatigue-resistant nanofibrous hydrogels that can closely mimic the bouligand structure of the natural hydrogel in the lobster underbelly. The resultant nanofibrous hydrogel can reach high nominal strength up to 8.4 MPa and high fatigue threshold up to 770 J/m2. We further demonstrate the superior impact resistance of the bioinspired bouligand-type nanofibrous hydrogel with specific penetration energy of 40 kJ/kg. We show that it is critical to weld the interfaces between nanofibers and introduce intrinsically high-energy phases (nanocrystalline domains) into nanofibers.