Stretchable, adhesive and ultra-conformable elastomer thin films.

Area of Science:

• Materials Science
• Polymer Science
• Surface Science

Background:

• Thermoplastic elastomers exhibit significant property changes around their glass transition temperature (T_g).
• Polystyrene (PS) has a high T_g (100 °C), while polystyrene-polybutadiene-polystyrene (SBS) has a low T_g (-70 °C).
• Thin films are crucial for advanced material applications requiring specific mechanical and adhesive properties.

Purpose of the Study:

• To prepare and characterize free-standing PS and SBS thin films.
• To investigate the mechanical properties and adhesion of these thin films on uneven surfaces.
• To establish the relationship between thin film properties and adhesion strength.

Main Methods:

• Gravure coating method for preparing thin films (hundreds of nanometers thick).
• Bulge testing and tensile testing for mechanical property evaluation.
• Adhesion testing on an artificial skin model with controlled roughness (R_a = 10.6 μm).

Main Results:

• SBS thin films exhibited a significantly lower elastic modulus (ca. 0.045 GPa) compared to PS thin films (ca. 1.19 GPa).
• SBS thin films demonstrated higher conformability and adhesion strength to a rough surface.
• Elastic modulus and thickness were identified as key factors correlating with conformability and adhesion.

Conclusions:

• SBS thin films offer superior adhesion to uneven surfaces due to their mechanical properties.
• The conformability of thin films is directly influenced by their elastic modulus and thickness.
• SBS thin films show potential as versatile coating layers for various materials, enhancing surface adhesion.