Two-dimensional correlation analysis of polyimide films using attenuated total reflection-based dynamic compression...

Area of Science:

• Materials Science
• Spectroscopy
• Polymer Chemistry

Background:

• Poly(p-phenylene biphenyltetracarboximide) is a high-performance polymer with applications requiring mechanical stability.
• Understanding its mechanical response at a molecular level is crucial for optimizing material properties.
• Infrared (IR) spectroscopy is a powerful tool for probing molecular vibrations and interactions.

Purpose of the Study:

• To investigate the dynamic mechanical response of poly(p-phenylene biphenyltetracarboximide) film under compression.
• To elucidate the role of intermolecular interactions in the material's dynamic behavior.
• To determine the sequence of molecular responses within the polymer structure during compression.

Main Methods:

• Attenuated total reflection (ATR)-based dynamic compression modulation two-dimensional (2D) correlation spectroscopy.
• Spectral simulation analysis using density functional theory (DFT).

Main Results:

• Dynamic 2D IR correlation spectra revealed distinct peaks in the imide I and imide II regions.
• The band at 1708 cm(-1) in the imide I region, attributed to intermolecular interactions, showed the largest dynamic response.
• Multiple peaks in the imide II region suggest compression-induced wavenumber shifts in backbone structures.
• Backbone regions (imide II) responded to compression before side-chain regions (imide I).

Conclusions:

• Intermolecular interactions significantly enhance the dynamic response of the polymer film.
• The observed spectral features are consistent with compression-induced shifts in molecular structures.
• A sequential response mechanism, with backbone regions reacting prior to side-chain regions, was identified during dynamic compression.