Nanoscience

However, chemical modification of the surface typically requires large amounts of organic solvents that are harmful to the environment. To solve this problem, many researchers have attempted to synthesize polymer-nanoparticle composites by using supercritical fluid (SCF)-based technology. Supercritical CO₂ has emerged as the most extensively studied SCF medium, because it is readily available, inexpensive, nonflammable, and environmentally benign.

Toyohashi Tech researchers in cooperation with researchers at the National Institute of Technology, Kurume College have investigated the formation of nanostructured material using supercritical CO₂. They have demonstrated the formation of composite nanoparticles of luminescent ZnO QDs and polymer by dispersion polymerization in supercritical CO₂. As a result of the supercritical-CO₂-assisted surface modification of QDs, the QDs were well dispersed in the polymer matrix and showed high luminescence.

“Unfortunately, the photoluminescence properties of pristine luminescent QDs were quenched in supercritical CO₂. The surface structure of the QDs was destroyed by supercritical CO₂,” explains associate professor Kiyoshi Matsuyama at the National Institute of Technology, Kurume College, “We found that the quenching of ZnO QDs could be prevented by coating with silica to obtain PMMA-ZnO composite QDs with high luminescence using a supercritical-CO₂-assisted surface modification with polymer.”

The research shows that the supercritical-fluid-assisted process provides an environmentally benign route for producing stabilized luminescent materials.

Story Source:

The above post is reprinted from materials provided by Toyohashi University of Technology. Note: Materials may be edited for content and length.

Journal Reference:

1. Kiyoshi Matsuyama, Yu-ki Maeda, Takaaki Matsuda, Tetsuya Okuyama, Hiroyuki Muto. Formation of poly(methyl methacrylate)-ZnO nanoparticle quantum dot composites by dispersion polymerization in supercritical CO₂. The Journal of Supercritical Fluids, 2015; 103: 83 DOI: 10.1016/j.supflu.2015.04.025

Toyohashi University of Technology. (2015, October 1). Semiconductor nanoparticles show high luminescence in a polymer matrix: Highly luminescent semiconductor nanoparticles immobilized in a polymer matrix using environmentally benign supercritical CO2. ScienceDaily. Retrieved October 10, 2015 from www.sciencedaily.com/releases/2015/10/151001093857.htm