Electrospining Machine: Wearable LIG Flexible Stress Sensor Based on Spider Web Bionic Structure

The research methods used include:

1. Preparation of LIG by laser induction: The graphene material used in the spider web structure sensor is laser-induced graphene (LIG), which is synthesized by scanning CO2 infrared laser on polyimide (PI). When the laser radiation energy reaches 5 J/cm², carbonization occurs on the surface of the PI film, and a photothermal reaction takes place on the PI, resulting in the formation of graphene with many five-membered and seven-membered rings.

2. Preparation of LIG/PDMS composite material: The LIG on the PI substrate was transferred to the PDMS by electrospinning machine to give the sensor good stability and tensile flexibility. Due to the 3D porous structure of graphene, the liquid PDMS can effectively penetrate into the pores of graphene, thus blending with LIG and interpenetrating with each other, and obtaining the LIG/PDMS composite material.

3. Laser engraving: A laser engraving machine combined with drawing software can engrave a spider web pattern of graphene on the PI.

Characterization

1. Observation with a scanning electron microscope (SEM, TM3030, Hitachi, Japan).

2. Fourier transform infrared absorption spectroscopy

3. Raman spectroscopy

4. Calculation of sensor sensitivity GF: Where R1 and R2 represent the resistance values at strains ε1 and ε2, respectively, and R0 is the initial resistance value.

5. Measurement of response changes: The resistance changes of the flexible sensor are measured with an LCR instrument through a pressure tester, and the data are substituted into the sensitivity formula.

6. Testing the dynamic performance of the sensor: 10%, 20%, and 30% strain loads are set to conduct cyclic tensile and release tests on the sensor, and step response cyclic tests are performed.

Research Highlights:

1. Inspired by natural bionics, this study manufactures a new type of graphene flexible stress sensor referencing the spider web structure, which has excellent resonance capabilities and overall structural robustness.

2. LIG/PDMS composites are produced by transferring LIG on PI substrate to PDMS through electrospinning machine, which solves the problem of poor stability and scalability of LIG devices formed on PI substrate. (Simple fabrication process, low manufacturing cost, good detection effect, ability to monitor tensile and bending deformation, and exceptionally good stability and reproducibility in the range of small mechanical bending deformations.)

Solved Problems:

The flexible stress sensor with spider web structure has the advantages of high sensitivity, wide working range, low hysteresis, high repeatability and stability, and is durable for a long time. The spider web structure is a network structure that extends from the center outward, connected end to end, and covers a wide range. Using this structure can make the sensor highly sensitive and stable. This shows that the sensor can be widely used in wearable sensing devices and the detection of human biological signals. It has certain development potential in practical applications in the fields of medical health, motion detection, etc.

Link：Wearable LIG Flexible Stress Sensor Based on Spider Web Bionic Structure