Continuous productions of highly fluorescent carbon dots and enriched polymer nanofibers via microfluidic techniques

Carbon dots (CDs) have shown great promise in various fields owing to their fascinating properties. However, most of high-performance CDs are usually synthesized upon intermittent operations, which are difficult to produce continuously in batch. In this regard, we develop a robust aluminum-based microfluidic chip reaction platform with imbibition-injection cycle feeding and ease of scale-up production, allowing the rapid and continuous synthesis of highly fluorescent CDs. The as-prepared CDs possess excellent optical properties, including high photoluminescence (PL) quantum yield (QY) of 71%, narrow full width at half maximum (FWHM) of 65 nm by optimizing the parameters of reaction. Combined with electro-microfluidic spinning, the continuous production of fluorescent enriched CDs/polymer nanofibers could further be realized. CDs/thermoplastic polyurethane (TPU) and CDs/polyamide 6,6 (PA66) nanofibers are prepared to exhibit enhanced mechanical properties with tensile strength 2.9 and 4.1 times higher than those of the pure polymer matrix, respectively. This work contributes a new kind of microfluidic chip for nanomaterial synthesis, and paves a way toward rapid and continuous preparation of high-performance CDs and CDs/polymers nanofiber films by microfluidic techniques.