Adhesion forces controlled by chemical self-assembly and pH: application to robotic microhandling

Area of Science:

• Materials Science
• Robotics
• Surface Chemistry

Background:

• Robotic microhandling is crucial for manufacturing microelectromechanical systems (MEMS).
• Adhesion forces at the micrometer scale significantly hinder precise micro-object release and positioning.
• Surface chemistry of both the micro-object and gripper influences adhesion.

Purpose of the Study:

• To investigate controlling adhesion in robotic microhandling using chemical self-assembled monolayers.
• To demonstrate the effect of liquid pH on adhesion forces during microhandling.
• To establish a reliable submerged robotic microhandling principle based on tunable surface chemistry.

Main Methods:

• Functionalization of gripper and micro-object surfaces with chemical self-assembled monolayers (SAMs).
• Specific SAMs studied include aminosilane-grafted 3-(ethoxydimethylsilyl)propylamine and (3-aminopropyl)triethoxysilane.
• Experimental manipulation of liquid pH to alter surface interactions and adhesion properties.

Main Results:

• Liquid pH can effectively modify adhesion, enabling a switch between attractive and repulsive behaviors.
• pH control allows for enhanced adhesion during handling and its cancellation during release.
• Experimental validation confirms the ability of pH control to precisely manage micro-object release.

Conclusions:

• Adjusting liquid pH is a viable strategy to control adhesion in submerged robotic microhandling.
• This approach offers a new principle for reliable micro-object manipulation in MEMS fabrication.
• Surface chemistry modification via SAMs combined with pH control provides a robust solution for microhandling challenges.