The Design, Synthesis, and Characterization of Photochromic and Mechanochromic Functional Fibers

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Mechanically responsive polymer materials offer unique stress-sensing capabilities.
• Applications in fibers are underexplored, limiting advanced material functionalities.
• Spiropyran (SP) mechanophores enable force-induced molecular changes.

Purpose of the Study:

• To develop novel mechanoresponsive and mechanochromic fibers.
• To investigate the fabrication and properties of SP-containing polyurethane fibers.
• To explore the potential for information storage and anti-counterfeiting.

Main Methods:

• Synthesis of a mechanoresponsive polymer by incorporating spiropyran (SP) into a polyurethane backbone.
• Fabrication of mechanochromic fibers using solution spinning.
• Tailoring mechanical sensitivity and mechanochromic response through hot stretching and pre-stretching.

Main Results:

• Colorless to blue color change observed in fibers upon tensile stress or UV irradiation due to SP activation.
• Mechanical sensitivity and response strain level are tunable via polymer chain orientation (hot stretching).
• Pre-stretched fibers demonstrated a mechanochromic barcode with dynamic information storage capabilities.

Conclusions:

• Mechanoresponsive and mechanochromic fibers were successfully fabricated.
• Fiber properties can be precisely controlled through post-processing techniques.
• These functional fibers present a novel platform for anti-counterfeit technologies and dynamic information display.