No abstract

There has been a growing interest in developing carbon-based polymer composites for electromagnetic interference (EMI) shielding materials. To achieve a high EMI shielding performance, the morphology of fillers in composites must be controlled. Although carbon fibers (CFs) have remarkable thermal and electrical properties and low density, their poor dispersion behavior within polymer matrix limits their practical applications as EMI shielding materials. In this study, we report an efficient method to disperse CFs within a thermoplastic polyurethane (TPU) matrix using pyranine-functionalized polyether (Polyether–pyranine) as a dispersing agent. Polyether–pyranine was grafted on the CF surfaces through π-π interactions between the CF and pyranine groups to produce surface-modified CFs (SCFs). Compared to CFs, the SCFs exhibited an improved dispersion stability within a TPU polymer matrix. Furthermore, a TPU composite with SCFs achieved an enhanced electrical conductivity and EMI shielding performance, which was primarily ascribed to the increased structural connectivity between the SCFs due to excellent dispersion.

Carbon dots (CDs) have attracted increasing attention in stabilizing Pickering emulsions due to their fascinating physicochemical properties. However, their practical use as Pickering emulsifiers has been limited due to the strong hydrophilic nature of the pristine CDs. Herein, the surface wettability of the CDs is simply tailored with hydrophobic hexyl isocyanates to produce surface-modified CDs (CD-Hs), and these are investigated as Pickering emulsifiers. Compared with the pristine CDs, CD-Hs showed strong adsorption at the oil–water interface, thereby exhibiting a high emulsification behavior. Furthermore, the effect of varying the density of hydrophobic hexyl isocyanates upon the emulsification behavior of the CD-Hs is investigated. Additionally, the practical applicability of the synthesized CD-Hs as the emulsifier is demonstrated in the Pickering emulsion polymerization process. Styrene-in-water emulsions stabilized by the CD-Hs are successfully polymerized to produce nanosized polystyrene (PS) particles with enriched fluorescent emission. Furthermore, the CD-stabilized PS particles exhibit adsorption performance toward heavy metal ions and organic dyes, demonstrating great potential for wastewater treatment. This study provides a promising approach for the design and fabrication of CD-based emulsion systems and hybrid materials.