Pressure tunable adhesion of rough elastomers.

Area of Science:

• Materials Science
• Surface Science
• Polymer Physics

Background:

• Controlling adhesion is crucial for technologies like wearable electronics and robotics.
• Existing methods include biomimetic structures, surface roughness, and chemical treatments.
• Polymer thin film dewetting has not been explored for adhesion control.

Purpose of the Study:

• To investigate polymer thin film dewetting as a novel method for surface modification to control adhesion.
• To analyze the relationship between dewetting-induced surface morphology and adhesive properties.
• To quantify adhesion changes using mechanical testing.

Main Methods:

• Polystyrene thin films were thermally annealed on polydimethylsiloxane substrates.
• Dewetting formed microscopic asperities on the substrate surface.
• Adhesion was measured using flat-punch normal indentation testing.

Main Results:

• Dewetting created stiff, microscopic asperities on the soft substrate.
• Asperity size correlated with pre-annealing film thickness.
• Large asperities significantly reduced adhesion; small asperities showed pressure-dependent adhesion.

Conclusions:

• Polymer thin film dewetting offers a new route to engineer surface adhesion.
• Surface morphology created by dewetting can tune adhesive performance.
• Pressure-dependent adhesion was observed on surfaces with small asperities.