Orthogonal Chemical Functionalization of Au/SiO₂/TiW Patterned Substrates

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Multimaterial substrates are essential for advanced nanodevices.
• Achieving selective surface functionalization on patterned multimaterial surfaces remains a challenge.
• Orthogonal functionalization strategies are needed for precise control over surface chemistry.

Purpose of the Study:

• To develop and demonstrate an orthogonal functionalization strategy for macropatterned and micropatterned gold/silicon dioxide/titanium tungsten (Au/SiO2/TiW) substrates.
• To selectively graft different molecules onto specific material areas of the patterned substrates.
• To validate the selectivity and efficiency of the functionalization process.

Main Methods:

• Orthogonal functionalization using monovalent silane, thiol, and phosphonic acid molecules.
• Selective grafting of thiol onto Au, phosphonic acid onto TiW, and silane onto SiO2 areas.
• Characterization of functionalization using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements.

Main Results:

• Successful orthogonal functionalization of Au/SiO2/TiW patterned substrates was achieved.
• Demonstrated selective grafting of specific molecules onto their intended material surfaces.
• XPS, ToF-SIMS, FTIR, and contact angle measurements confirmed the successful and selective surface modification.

Conclusions:

• The developed orthogonal functionalization method provides precise control over surface chemistry on patterned multimaterial substrates.
• This technique is highly promising for the selective anchoring of various targets, including biomolecules and nanoparticles.
• The approach is valuable for fabricating advanced nanodevices, such as nanosensors and other nanodevices.