Increasing the Mechanical Stability of Polymer-Gold Interfacial Connection: A Parallel Covalent Strategy

Area of Science:

• Materials Science
• Surface Chemistry
• Polymer Science

Background:

• Thiol-gold (S-Au) chemistry is a common method for functionalizing gold surfaces.
• S-Au self-assembled monolayers exhibit instability under mechanical stress, limiting applications.
• Developing robust surface modifications is crucial for advanced functional materials.

Purpose of the Study:

• To report a novel surface-modifying procedure using a parallel covalent strategy.
• To enhance the interfacial connecting strength between gold surfaces and polymers.
• To overcome the instability issues associated with S-Au chemistry.

Main Methods:

• Utilizing dendritic macromolecules as an interfacial "middle layer" between gold and polymer.
• Employing atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS) to quantify interfacial strength.
• Conducting control SMFS experiments, fluorescent microscopy, and dynamic force spectroscopy to confirm cleavage structure.

Main Results:

• The dendritic macromolecule layer increased interfacial connecting strength by at least 350%.
• The study confirmed amide bonds as the ultimate cleavage structure.
• The new method demonstrated significantly improved mechanical stability compared to S-Au chemistry.

Conclusions:

• The parallel covalent strategy with dendritic macromolecules offers a robust alternative to S-Au chemistry.
• This approach enables the preparation of stable, stimuli-responsive polymer brushes on solid surfaces.
• The findings facilitate the study of mechanophores with enhanced force stability.