Bioinspired Temperature-Responsive Multilayer Films and Their Performance under Thermal Fatigue

Area of Science:

• Materials Science
• Bioinspired Engineering
• Nanotechnology

Background:

• Nonliving tissues can exhibit self-shaping and self-folding behaviors in response to environmental stimuli.
• These movements arise from generated stresses within anisotropic multilayer structures.
• Understanding and replicating these properties can lead to novel responsive materials.

Purpose of the Study:

• To present bioinspired responsive anisotropic multilayer films.
• To detail a low-cost fabrication process for these materials.
• To investigate their thermal deformation capabilities and thermal fatigue resistance.

Main Methods:

• Fabrication of anisotropic multilayer films using low-cost techniques.
• Utilizing a mismatch in thermo-mechanical properties between three or more anisotropic thin layers.
• Incorporating anisotropic homogenous metallic strips over an anisotropic thermoplastic layer.
• Testing material deformation in response to temperature changes (<40 °C).
• Assessing thermal fatigue performance, including failure modes and crack formation.

Main Results:

• Developed anisotropic multilayer films that deform with small temperature changes.
• Demonstrated controlled geometric transformation of the materials.
• Identified a promising fabrication process.
• Established a strong correlation between fabrication method, strip thickness, and thermal fatigue performance.
• Analyzed the effects of thermal cycling on material sensitivity, failure modes, and crack formation.

Conclusions:

• Bioinspired responsive anisotropic multilayer films can be fabricated using low-cost methods.
• These materials passively react to temperature stimuli by altering their geometry.
• The thermal fatigue performance is dependent on fabrication parameters and material thickness.
• The developed materials show potential for applications requiring passive thermal responsiveness.