The synthesis of well defined nanoparticles with green chemistry has been an area of intense investigation, but still requires development. In this study, we propose a novel approach for controlling the particle size and distribution through diffusion-controlled growth of plasma-assisted electrochemical synthesis. The continuous, controlled addition of an Au precursor with syringe pump successfully controls the particle size in the range of 50-300 nm with a monodisperse size distribution. Moreover, gold nanoparticles can be formed successfully without any stabilizer and reducing agent. Through optimization of the reaction parameters, including the reaction temperature, discharge current of the microplasma, pH, and concentration of D-(-)-fructose, we verify two distinct feature of diffusion-controlled growth that the particle growth is good agreement of theoretical growth rate (r ∼ t 1/3) and the formed gold nanoparticles exhibit polyhedral or near-spherical shapes. This method has been applied to synthesize Au@Ag core-shell nanoparticles and control the Ag shell thickness.
The authors drive a plasma-induced reduction reaction of the gold precursor by alternating current (AC)-driven atmospheric pressure plasma at the plasma-liquid interface. They systematically study the plasma-induced reaction at the plasma-liquid interface and observe that the reduction reaction is a proportionality relationship to the root mean square current of AC-driven atmospheric pressure plasma. Here, the technique has been applied to the plasma-polymeric film interface and demonstrates a direct writing technique to create the patterned metal nanoparticles. The authors find that the pattern properties are significantly related to the absorbed de-ionized (DI) water in the polymeric film. To prove their conceptual idea, the authors newly design an electrospun mat made of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and poly(styrene-block-butadiene-block-styrene) and control the absorption ability of de-ionized water and ethanol in a polymeric film. The results demonstrate that the absorbed DI water plays a key role in the plasma-induced reaction at the plasma-polymeric film.
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