Control of adhesion via internally pressurized subsurface microchannels

Area of Science:

• Materials Science
• Adhesion Science
• Microfluidics

Background:

• Standard pressure-sensitive adhesives (PSAs) rely on viscoelastic glue layers between adherents.
• Existing PSAs lack mechanisms for active control over adhesion properties.
• Microchannel integration offers a novel approach to manipulate adhesive behavior.

Purpose of the Study:

• To investigate the design and adhesive properties of PSAs embedded with microchannels.
• To explore the effect of internal channel pressure on adhesion and debonding hysteresis.
• To determine how channel geometry and surface characteristics influence tunable adhesion.

Main Methods:

• Fabrication of viscoelastic adhesive layers with integrated microchannels.
• Indentation and retraction experiments using a rigid cylindrical indenter.
• Controlled pressurization (positive and negative) of internal microchannels.
• Measurement of adhesion forces and debonding hysteresis during indenter retraction.

Main Results:

• Adhesion hysteresis was observed due to differential debonding loads between the indenter and internal channel surfaces.
• Varying internal channel pressure altered contact areas and significantly modulated adhesion hysteresis.
• Hysteresis peaked at intermediate internal pressures and increased with adhesive skin thickness over channels.

Conclusions:

• Subsurface microchannels provide a method for actively controlling adhesive properties.
• Tunable adhesion is achieved through the interplay of channel design, surface properties, and internal pressure.
• This technology enables large-range manipulation of adhesion for advanced applications.