Fabrication of Photoluminescent Coatings Composed of Boron and Nitrogen Co-doped Carbon Dots on the Cotton Fabric by Layer-by-Layer Self-assembly Method

Boron and nitrogen co-doped carbon dots (BN-CDs) were synthesized by one-pot hydrothermal carbonization. Then the as-prepared CDs was combined with alginate and polyethyleneimine to fabricate the multi-layered coating on the cotton fabric by Layer-by-Layer (LbL) self-assembly method. The CDs containing coating emitted visible blue light under 365 nm UV lamp. Subsequently, the UV protection property, thermal stability, flame retardancy and wash durability of the CDs treated cotton fabric were investigated. The ultraviolet protection factors of pure cotton fabric and cotton fabric treated with 12 bilayers CDs consisting coating were 6.48 and 64.10, respectively, which indicated that the synthesized CDs was an efficient UV absorber. In TGA test, more char residues at 700°C were observed for CDs consisting coatings treated cotton fabrics under nitrogen atmosphere. After B, N co-doped CDs were enriched in the PEI/alginate multi-layered coating, the PHRR of cotton-CDs-12BL were reduced 15% and T PHRR of cotton-CDs-12BL were improved 26.4°C in microscale combustion calorimeter test. This result indicated that B, N co-doped CDs presented potential application as a flame retardant on surface of cotton fiber.