Highly polymerized linear polyimide /H₃PW₁₂O₄₀ photocatalyst with full visible light region absorption

Area of Science:

• Materials Science
• Polymer Chemistry
• Photocatalysis

Background:

• The degree of polymerization in polyimides significantly impacts their photoelectric properties, including light absorption and charge carrier recombination.
• Conventional methods to increase polyimide polymerization, such as high temperatures, are limited by material decomposition.
• Enhancing polyimide polymerization is crucial for optimizing their performance in applications like photocatalysis.

Purpose of the Study:

• To investigate the use of phosphotungstic acid to increase the degree of polymerization of polyimides at lower temperatures.
• To improve the light absorption capability and reduce charge carrier recombination in polyimide-based composites.
• To compare the performance of linear polyimide/phosphotungstic acid composites with cross-linked counterparts.

Main Methods:

• Introduction of phosphotungstic acid into the polyimide synthesis process.
• Utilizing p-phenylenediamine based polyimide with a one-dimensional linear polymer chain structure.
• Formation of polyimide/phosphotungstic acid composites and evaluation of their photoelectric properties.

Main Results:

• Phosphotungstic acid effectively increased the degree of polymerization of polyimide at reduced temperatures.
• The polyimide/phosphotungstic acid composite exhibited enhanced light absorption compared to polyimides polymerized conventionally.
• Linear polyimide/phosphotungstic acid composites demonstrated stronger light absorption capacity than cross-linked versions due to a stronger POM-π effect.

Conclusions:

• Phosphotungstic acid is a viable additive for promoting polyimide polymerization at lower temperatures.
• The enhanced polymerization leads to improved light absorption and reduced electron-hole recombination, benefiting photoelectric applications.
• Linear polyimide structures, when combined with phosphotungstic acid, offer superior performance in light absorption compared to cross-linked systems.