Supramolecular self-assemblies formed by co-assembly of carbon dots and tannic acid

In recent years, it is heartening to witness that carbon dots (CDs), a rising star in the family of carbon nanomaterials, have displayed tremendous applications. However, the investigations toward self-assembly of CDs are still in their infancy. Tannic acid (TA) is a naturally derived polyphenolic compound with special molecular structure. Here, the co-assembly of CDs and TA in aqueous solutions has been investigated. The CDs/TA binary mixtures exhibited rich phase behavior, which went through the process of transparent phase-turbid phase-transparent phase. We focus on investigating the morphologies of the samples. As the concentration of TA increases, the aggregates evolve from the network structures to the spherical aggregates, and finally become the vesicles. Through systemic analysis of changes of zeta potential, morphologies and size distributions at varying temperature and pH, the mechanism of aggregate formation is proposed. The effect of adding TA on the fluorescence properties of CDs aqueous solutions was studied. After integration into aggregates, the potential applications of the CDs in biology and life sciences could be significantly expanded.