Precise Controlling of Friction and Adhesion on Reprogrammable Shape Memory Micropillars

Area of Science:

• Materials Science
• Surface Engineering
• Smart Materials

Background:

• Stimuli-responsive microstructured surfaces offer tunable properties but lack precise control.
• Achieving controlled morphological changes in microstructures for regional property manipulation is challenging.

Purpose of the Study:

• To create a microstructured surface with precisely controllable morphological changes using near-infrared (NIR) light.
• To demonstrate tunable friction and adhesion properties on demand.

Main Methods:

• Fabrication of carbonyl iron particle-doped shape memory polyurethane micropillars.
• Utilizing remote NIR irradiation to induce reversible transitions in micropillar morphology (bent and upright states).
• Characterization of friction transitions and water droplet adhesion forces.

Main Results:

• Successfully realized micropillars with precisely controllable morphological changes upon NIR irradiation.
• Demonstrated reversible friction transitions with coefficients ranging from ~0.8 to ~1.2.
• Showcased reversible switching of water droplet adhesion force between ~160 and ~760 μN.

Conclusions:

• The developed smart stimuli-responsive micropillar arrays enable precise, remote, and on-demand control of surface friction and wettability.
• Potential applications include refreshable Braille displays, micro-particle motion control, lab-on-a-chip, and microfluidics.