Characterization of metal-supported poly(methyl methacrylate) microstructures by FTIR imaging spectroscopy

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Thin poly(methyl methacrylate) (PMMA) films with microstructured pores can function as scaffolds for biosensor arrays.
• These microstructures create miniaturized reaction vessels or detector elements for biosensing applications.

Purpose of the Study:

• To characterize the chemical information and microstructure of PMMA films on gold substrates using FTIR spectroscopic imaging.
• To investigate the interactions between PMMA residues and the gold substrate within the microstructured pores.

Main Methods:

• Preparation of microstructured PMMA films on gold substrates using optical lithography.
• Analysis of PMMA microstructure and chemical composition using Fourier Transform Infrared (FTIR) spectroscopic imaging.
• Characterization of PMMA-gold interactions by analyzing the carbonyl band and identifying additional spectral features.

Main Results:

• FTIR spectroscopic imaging provided laterally resolved chemical information of the microstructured PMMA films.
• Small amounts of PMMA residues were detected inside the micropores.
• A 5 cm(-1) downshift in the carbonyl band indicated interactions between PMMA residues and the gold substrate.
• Formation of carboxylate species during microstructuring was observed.
• Three types of strong PMMA-gold interactions involving carbonyl or carboxyl oxygen were discussed.

Conclusions:

• Microstructured PMMA films on gold are suitable scaffolds for biosensor arrays.
• PMMA-gold interactions, particularly involving carbonyl or carboxyl oxygen, are significant and influence sensor performance.
• FTIR spectroscopic imaging is an effective technique for characterizing these microstructured films and their interfacial properties.