The reporter learned from the University of Science and Technology of China that Professor Du Pingwu's research group has synthesized the first long conjugated segment of a single chiral index single-walled carbon nanotube in the world through precise molecular design. The result was published in the cover of the Journal of the American Chemical Society recently as a cover article.
Carbon nanotubes can be considered as all-carbon based tubular conjugated polymers containing only sp2 bonded atoms. However, there is no research report on long conjugated polymers with specific diameters of carbon nanotube fragments. Pure carbon nanotube materials with a single diameter and chirality have important application potential in the field of nanotechnology and electronics, but the synthesis of such carbon nanotubes is an important challenge in the fields of synthetic chemistry and materials chemistry. The catalyst surface-mediated growth method shows great potential in the preparation of carbon nanotubes, but the purity of nanotubes is always an insurmountable problem.
Based on the previous series of work on the synthesis and physical properties of new structures of carbon nanotubes, the researchers skillfully introduced the bifunctional structure onto the curved conjugated small molecule carbon ring. Subsequently, the fragment was extended in one dimension by nickel-catalyzed coupling reaction, and a long conjugated segment of single-walled carbon nanotubes with a fixed diameter was constructed using gel permeation chromatography, nuclear magnetic, infrared and Raman Spectroscopic and other characterization methods confirmed the successful synthesis of long conjugated polymers of carbon nanotubes. Using wide-angle diffractometry, it was found that the polymer solid film had obvious diffraction rings and showed a certain degree of crystallinity. Comparing the absorption, fluorescence and fluorescence attenuation curves of monomers and conjugated polymers, it was found that the increase in the degree of conjugation also greatly improved the photophysical properties of the polymers.
The long conjugated segment is the world's first conjugated polymer compound that is structurally close to an armchair-type single-walled carbon nanotube. Ultra-pure single-walled carbon nanotubes provide corresponding conjugated polymer templates, and also provide an important reference for the preparation and properties of single chiral carbon nanotubes by solution method. (Reporter Wu Changfeng)
Concrete sealer also named as concrete sealing hardener, concrete densifier etc, is important surface treatment for concrete floor. It is provided with lithium silicate type end product for concrete sealer and raw materials like pure lithium silicate and potassium silicate.
Concrete Floor Sealer,Concrete Sealing Hardener,Lithium Based Concrete Sealer,Concrete Densifier And Hardener
Shanghai Na Long Tech Co., Ltd , https://www.na-long.com