Polymer Morphological Change Induced by Terahertz Irradiation.

Area of Science:

• Polymer Science
• Materials Science
• Terahertz Spectroscopy

Background:

• Terahertz (THz) frequencies align with polymer intermolecular vibrational modes.
• THz wave irradiation can influence macromolecular polymorphs, affecting polymer properties.
• Low THz photon energy allows for soft conformational changes without chemical damage.

Purpose of the Study:

• To investigate the effect of THz wave irradiation on polymer crystallization.
• To explore the potential of THz waves for non-damaging material manipulation.
• To demonstrate THz-induced intermolecular rearrangement in polymers.

Main Methods:

• Irradiation of poly(3-hydroxybutylate) (PHB) in chloroform solution during solvent casting crystallization using a free electron laser (FEL) generated THz wave.
• Morphological observation of crystal formation.
• Analysis of infrared (IR) absorption spectra to determine crystallinity.

Main Results:

• Formation of micrometer-sized crystals was observed upon THz wave irradiation.
• A 10-20% increase in crystallinity was measured.
• The effective THz peak power density was 40 MW/cm(2), significantly lower than conventional laser intensities.

Conclusions:

• THz wave irradiation effectively induces intermolecular rearrangement of polymer macromolecules.
• This method offers a novel, low-energy approach for controlling polymer morphology and crystallinity.
• THz waves present a promising tool for soft material manipulation in polymer science.