Mechanochromic Polymer Film with High Sensitivity toward Tensile Strain by the Post-Curing Ring-Closure Induced...

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Mechanochromic materials offer straightforward in situ stress/strain monitoring in polymers.
• Low sensitivity to tensile strain is a major limitation for practical applications.

Purpose of the Study:

• To develop a strategy for enhancing the mechanochromic sensitivity of polymer films toward tensile strain.
• To investigate a molecular-scale pre-stretching method for mechanochromic agents.

Main Methods:

• Molecular functionalization to induce ring-opening of mechanochromic agents.
• Post-curing ring-closure at elevated temperatures to pre-stretch agents within a crosslinked network.
• In situ fluorescent measurements during tensile testing and visco-elastic measurements.

Main Results:

• Demonstrated enhanced mechanochromic sensitivity with early activation at 50% tensile strain.
• Confirmed the pre-stretching effect in polymer films with various compositions.
• Elucidated the mechanism of mechanochromic activation through visco-elastic analysis.

Conclusions:

• A novel strategy effectively enhances mechanochromic sensitivity by pre-stretching agents at the molecular level.
• The simple and effective method provides an alternative for improving tensile strain detection in mechanochromic polymers.
• This approach holds potential for broader applications in stress monitoring technologies.