چكيده به لاتين
The synthesis of various nanomaterials has garnered significant attention in recent decades. Among them, silver nanoparticles have found numerous applications in industries such as healthcare, pharmaceuticals, electronics, and more, due to their notable optical, electrical, and biological properties. Synthesis methods for nanoparticles are generally categorized into two approaches: bottom-up and top-down. Within this classification, chemical reduction stands out as the most commonly used method due to its simplicity, cost-effectiveness, and accessibility. This method is based on the reduction of silver ions to silver atoms, followed by the formation of nanoparticles through particle aggregation.
With advancements in microfluidics, microreactors have been employed over the past two decades for the synthesis of various nanoparticles, including silver, thanks to their good controllability and mass transfer capabilities. However, these methods face several common challenges, such as the high cost of microfluidic chip and equipment fabrication, clogging of microchannels (especially during phase changes), and limitations in applying high flow rates.
In this study, to address these challenges, a robotic microfluidic platform is proposed that operates by manipulating and mixing droplets on a superhydrophobic surface using a robotic arm. This arm is connected to a syringe that moves and mixes the droplets by adhesion forces when in contact with them. While this system can discretely merge droplets, at high frequencies, it can function as a continuous microreactor. In the chemical reduction process for synthesizing silver nanoparticles, improved mixing is a crucial factor, and many studies are currently exploring this aspect.
In this study, silver nanoparticles were synthesized using the chemical reduction method, with silver nitrate as the precursor, sodium borohydride as the reducing agent, and PVP and sodium hydroxide as stabilizers, all integrated into the robotic microfluidic platform. UV-Vis spectroscopy, dynamic light scattering (DLS), and zeta potential measurements were performed to confirm the presence and size of silver nanoparticles. The spectroscopy results showed a peak wavelength between 392-402 nm, indicating the presence of spherical silver nanoparticles of appropriate size. The full width at half maximum (FWHM) of the absorption peak ranged from 62-82 nm, which suggests proper distribution of the silver nanoparticles. The DLS measurements revealed nanoparticles with diameters between 12-20 nm and a distribution of ±4-5 nm. Additionally, zeta potential results with values of -50 mV to -51 mV indicated excellent stability of the synthesized nanoparticles.
