Synthesis Of Monodispersed Colloidal Carbon Spheres Via Two-stage Hydrothermal Method

The term "monodispersed particles" means a group of particles made highly uniform in size and shape. The major significance of monodispersed particles is attributed to the uniformity in physical-chemical properties of individual particles in a dispersion system, which allows us to directly correlate the properties of a whole system with those of each particle and facilitates theoretical approaches. Thus, they are of obvious importance not only in the fields of physical chemistry, dealing with the dynamic behavior and stability of particulate systems, but also in the industries including catalysts, ceramics, electromagnetic materials, pigments, medicines, etc.Herein, we report on synthesis of monodisperse colloidal carbon spheres by two-stage hydrothermal method using glucose as carbon source. As produced homogeneous "seeds" were reloaded in hydrothermal condition to synthesize micro-sized uniform colloidal carbon spheres. Furthermore, we also discussed the effects of parameters (concentration from 0.05 to 0.5mol/L, temperature from 160 to 205℃, conservation time from 4 to 8h) which concerned the uniformity of shape and size in detail. The predominance of carbon spheres produced by hydrothermal method has been reserved, including environment-friendly without any toxic organic solvent, hydrophilic and reactive surfaces full of functional groups, controllable size distribution and so on.We also explain the mechanism of the formation for the monodisperse colloidal carbon spheres. "seeds" are introduced into a monomer solution under a relatively low super saturation below the critical level for nucleation. The "seeds" may positively reduce the super saturation to prevent the spontaneous nucleation itself. As a consequence, seeding is a useful technique for the synthesis of monodispersed particles even in originally polydisperse systems...