Robust Thick Polymer Brushes Grafted from Gold Surfaces Using Bidentate Thiol-Based Atom-Transfer Radical...

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Chemistry

Background:

• Self-assembled monolayers (SAMs) are crucial for surface functionalization.
• Atom-transfer radical polymerization (ATRP) is a versatile technique for polymer synthesis.
• Thermal stability of SAMs is a key limitation for high-temperature surface-initiated polymerizations.

Purpose of the Study:

• To design and synthesize a novel bidentate alkanethiol for enhanced SAM thermal stability.
• To investigate the thermal stability and characteristics of SAMs formed from the new molecule.
• To evaluate the performance of these SAMs in surface-initiated ATRP at elevated temperatures.

Main Methods:

• Synthesis of 16-(3,5-bis(mercaptomethyl)phenoxy)hexadecyl 2-bromo-2-methylpropanoate (BMTBM).
• Formation and characterization of SAMs using ellipsometry, XPS, and PM-IRRAS.
• Solution-phase thermal desorption tests to assess SAM thermal stability.
• Surface-initiated ATRP of methyl methacrylate and styrene at various temperatures.

Main Results:

• BMTBM formed bidentate SAMs with significantly higher thermal stability compared to monotoate analogs.
• The enhanced stability is attributed to the chelate effect of the bidentate structure.
• BMTBM SAMs successfully supported polymer brush growth up to 120 °C.
• Monotoate SAMs failed to support polymer growth above 100 °C.

Conclusions:

• Bidentate adsorbate design offers a route to highly thermally stable SAMs.
• The developed BMTBM SAMs provide a robust platform for high-temperature surface-initiated ATRP.
• This approach enables the synthesis of thicker polymer brushes under demanding thermal conditions.