UV- and Thermally-Active Bifunctional Gelators Create Surface-Anchored Polymer Networks

Area of Science:

• Polymer Chemistry
• Materials Science
• Surface Chemistry

Background:

• Surface-attached polymer networks are crucial for advanced material applications.
• Developing efficient and versatile synthesis methods is an ongoing challenge in polymer science.

Purpose of the Study:

• To report a versatile one-step synthesis of surface-attached polymer networks.
• To investigate the reaction mechanism and gel formation of small bifunctional gelators (SBGs).
• To compare UV and thermal initiation for polymer network formation.

Main Methods:

• Synthesis of surface-attached polymer networks using 4-azidosulfonylphenethyltrimethoxysilane (4-ASPTMS) and 6-azidosulfonylhexyltriethoxysilane (6-ASHTES).
• Deposition of precursor polymer and SBG mixture on silicon wafers.
• Initiation of crosslinking via UV irradiation (≈254 nm) or thermal annealing (>100 °C).
• Characterization using spectroscopic ellipsometry (SE) and FTIR-ATR.

Main Results:

• Successful one-step synthesis of crosslinked polymer networks covalently attached to surfaces.
• Both UV and thermal methods induce gelation through sulfonyl azide decomposition and tri-alkoxy condensation.
• 4-ASPTMS is UV-active due to its aromatic nature, forming gels upon UV irradiation, while 6-ASHTES is UV-inactive.
• Thermal initiation is effective for both SBGs, yielding analogous gelation.

Conclusions:

• The developed method offers a versatile approach for creating surface-attached polymer networks.
• The choice of SBG and initiation method (UV vs. thermal) influences network formation.
• The aromaticity of 4-ASPTMS plays a key role in its UV-induced crosslinking capability.