Researchers at University of Tsukuba, Japan, have developed a groundbreaking method for synthesizing polyaniline—a conductive polymer exhibiting golden luster—marking the first successful attempt globally. The reflection spectrum of this polyaniline resembles that of metallic gold. The polymer was synthesized by a two-step process: the creation of precursor microparticles and the subsequent chemical polymerization.

Tsukuba, Japan—Polyaniline, a conductive polymer typically synthesized in water and appears dark green, exhibits different properties based on its synthesis and processing conditions. The researcher team involved in this study successfully synthesized polyaniline, with golden luster, in two stages. In the first stage, fine particles were prepared using short-time electrochemical polymerization, high-voltage spark treatment, and other methods, and in the second stage, chemical polymerization was applied. Notably, the electrical conductivity of this golden polyaniline is lower than that of polyacetylene, making it unsuitable for transmitting large currents. However, this golden polyaniline has the potential to revolutionize the electronic sector because of its applicability in micro-organic semiconductor thin-film and other similar devices.

The reflectance spectrum of the newly developed golden polyaniline is similar to that of gold. The metallic luster of polyacetylene, a conventional conductive polymer, is based on the plasma reflection of free electrons owing to the high density of π-electrons within the molecule. In contrast, the metallic luster of the newly synthesized gold-colored polyaniline is attributed to a combination of polarons, which are carriers responsible for conductivity, and surface luster.

Original Paper

Title of original paper:

Preparation of Golden polyaniline and interpretation with a Lorentz model

Journal:

Next Materials (Elsevier)

DOI:

10.1016/j.nxmate.2025.100582

Correspondence

Associate Professor GOTO Hiromasa
Institute of Pure and Applied Sciences, University of Tsukuba

Related Link

Institute of Pure and Applied Sciences