2H and 4H silver colloidal suspension synthesis, as a new potential drug carrier.

• Diffusion impact on the silver nanoparticles crystal structure is shown. • Hexagonal crystal structure 4H and 2H of Ag nanoparticles were synthesized. • 4H and 2H crystals transform to more dense packed FCC. • Mass synthesis of 4H and 2H structure is possible. In this paper diffusion impact on the silver nanoparticles synthesis and their crystal structure is shown. For this purpose, comparative studies between continuous flow two-phase microdroplets systems vs. two-phase batch reactor were performed. Such two-phase configuration of the investigated system makes it possible to study the impact of mass transfer phenomenon on the nanoparticles formation process. In the case of two-phase microdroplets system, diffusion is replaced by convection, accelerated by interphase friction between water droplets and a continuous organic phase. It was concluded that under diffusion control it was possible to obtain silver nanoparticles with a hexagonal crystal structure. Moreover, for the first time using a chemical method, and diffusion rate-limiting step, the hexagonal structure 4H and 2H of Ag nanoparticles were synthesized. We suggest, that such hexagonal crystals can be applied as a smart drug delivery system, where the drug releases can be controlled by short light impulse. In effects, thermodynamically unstable 4H and 2H crystals transform to more dense-packed FCC structure. [ABSTRACT FROM AUTHOR]