Southeast University has developed a thin-film flexible sensor for real-time color sensing and electrical signal monitoring

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Practical application

By using the template forming method, the film can be easily designed in different patterns, such as fish, six-leaf flower and four-leaf clover
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In this process, hybrid films with different structural colors are first produced
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Based on the aforementioned self-healing properties, the fragments can be glued together to form a complete object
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These complex patterned films make them functional materials in different fields
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Figure 4 Patterned self-healing hybrid structural color film
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ac) Schematic and optical images of color films of various patterned self-healing hybrid structures with a) fish, b) six-leaf flower, and c) four-leaf clover shapes
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Considering its electrical conductivity, adhesion, self-healing, and structural color sensing capabilities, the composite film is expected to be used in flexible electronics
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To illustrate this, joint motion was monitored by directly affixing the membranes to the fingers, wrist, and elbow, respectively
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In the case of finger movement, when the bending angle gradually increases, the structural color of the film transitions from orange-red to green, and even if the finger moves continuously, it shows good stability and excellent optical sensing performance
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At the same time, real-time resistance changes were recorded.
With the deformation of the finger, the resistance value of the film increased or decreased accordingly
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The film exhibits color-changing ability and stable and sensitive conductivity in dynamic activities, and has potential applications in flexible human motion sensors for real-time color sensing and electrical signal monitoring
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Figure 5.
Conductivity responses to various real-time human motions
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ac) Photographs of polymer conductive hydrogel hybrid structural color films responding to bending motion of a) finger, b) wrist, and c) elbow, respectively
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α, β, and γ denote the bending angles of the finger, wrist and elbow bending motions, respectively
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df) Wavelength shift values ​​of the films, corresponding to different bending angles of d) finger, e) wrist and f) elbow, respectively
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gi) The relative resistance of the hybrid structural color film varies with different angles of g) finger, h) wrist and i) elbow
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Highlights Summary

In summary, inspired by natural organisms, the authors introduced CNTs-PDA fillers into PU inverse opal scaffolds to develop a new type of elastic polymer conductive hydrogel hybrid structural color film
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The film has stable tensile properties and bright structural color
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In addition, the presence of carbon nanotubes endows the film with good electrical conductivity, and utilizing the advantages of PDA, the film has excellent adhesion and self-healing properties
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Due to the responsiveness of structural colors, the prepared films have the ability to change color and can be used as dual-signal flexible human motion sensors for real-time color sensing monitoring and electrical signal monitoring
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