Electrospinner: In situ grown silk fibroin nanoparticles enhanced photocurable 3D printed flexible strain sensors

Background

With the development of flexible electronics and wearable technology, there is an increasing demand for flexible strain sensors. Such sensors need to have excellent mechanical properties, sensitivity, and customizability. This study proposes an ion-conductive gel based on in situ generated silk fibroin nanoparticles (SFN) for photocurable 3D printing to meet these needs.

Preparation and characterization of SFN

The sericin component in silkworm cocoons is removed and converted into loose white flakes as the base material of SFN. The in situ generation of SFN is achieved using ionic liquid [EMIM]Ac as a non-aqueous solvent, and the uniform dispersion of SFN is achieved by high-speed shear mixing.

Printability of PCR/SFN system

The printability of the PCR/SFN system was evaluated using experiments using a commercial DLP 3D printer, including key parameters such as viscosity, photopolymerization rate, and transparency.

Mechanical properties testing

The tensile and compressive properties of the 3D-printed PCR/SFN ion gel were studied, and it was found that the addition of SFN significantly improved the tensile and compressive strengths of the gel.

Electrical sensing performance test

The resistance change of PCR/SFN ion gel strain sensor was explored, and it was found that it had high sensitivity in different strain ranges and showed stable resistance change in dynamic cyclic loading test.

Application of human motion monitoring

The customized porous structure flexible sensor component prepared by 3D printing technology realized the customization of sensing behavior and ensured excellent stability and sensitivity.

Connection with electrospinning

BFCUR was loaded into electrospun nanofibers (ENF) with high specific surface area, which further improved the detection sensitivity. The BFCUR-loaded ENFs sensor showed an ultra-low LOD of 22 ppb for ammonia and was successfully applied to the breath ammonia detection of healthy volunteers, patients with chronic kidney disease and patients with Helicobacter pylori infection, showing great application potential

Conclusion

This study successfully prepared SFN-enhanced DLP 3D printed PCR ion gel through an in situ growth strategy, significantly improved the mechanical properties of the ion gel, and combined with photocuring 3D printing technology, gave the SFN gel extremely high design freedom. The prepared stretchable, low-hysteresis SFN-containing ion gel porous structures exhibited excellent performance as highly sensitive strain sensors. These 3D-printed nanocomposite ion gels made with in situ grown SFNs provide a promising approach for the development of flexible strain sensors and pave the way for the development of wearable electronic devices.

Electrospinning Nanofibers Article Source:

https://doi. org/10.1016/j.cej.2024.154762.