Impact of Environmental Conditions (pH, Ionic Strength, and Electrolyte Type) on the Surface Charge and Aggregation of Silver Nanoparticles Suspensions
Impact of Environmental Conditions (pH, Ionic Strength, and Electrolyte Type) on the Surface Charge and Aggregation of Silver Nanoparticles Suspensions
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DOI：
10.1021/es902240k
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发表时间：
2010-02-15
影响因子：
11.4
通讯作者：
Tolaymat, Thabet M.
中科院分区：
文献类型：
--
作者：
El Badawy, Amro M.;Luxton, Todd P.;Tolaymat, Thabet M.
研究了封端剂和环境条件（pH、离子强度和背景电解质）对银纳米颗粒（AgNPs）悬浮液表面电荷和聚集电位的影响。封端剂是用于合成纳米颗粒以防止聚集的化学品。研究中检查的AgNP如下：（a）未涂覆的AgNP（H-2-AgNP），（B）静电稳定的（柠檬酸盐和NaBH 4-AgNP），（c）空间稳定的（聚乙烯吡咯烷酮（PVP）-AgNP），和（d）静电稳定的（支链聚乙烯亚胺（BPEI）-AgNP）。未涂覆的（H-2-ANP）、柠檬酸盐和NaBH 4涂覆的AgNP在较高的离子强度（100 mM NaNO 3）和/或酸性pH（3.0）下聚集。对于这三种纳米材料，氯化物（Cl-，10 mM）作为背景电解质，即使在低pH值（3.0）下，流体动力学直径的变化也很小。这受到残余银离子的存在的限制，这导致形成稳定的带负电荷的AgCl胶体。此外，Ca 2+（10 mM）的存在下，导致聚集的三个先前确定的银纳米粒子，无论pH值。至于PVP涂层的银纳米粒子，离子强度，pH值和电解质类型没有影响的空间稳定的银纳米粒子的聚集。BPEI包覆的AgNP的表面电荷和聚集根据溶液pH而变化。
The impact of capping agents and environmental conditions (pH, ionic strength, and background electrolytes) on surface charge and aggregation potential of silver nanoparticles (AgNPs) suspensions were investigated. Capping agents are chemicals used in the synthesis of nanoparticles to prevent aggregation. The AgNPs examined in the study were as follows: (a) uncoated AgNPs (H-2-AgNPs), (b) electrostatically stabilized (citrate and NaBH4-AgNPs), (c) sterically stabilized (polyvinylpyrrolidone (PVP)-AgNPs), and (d) electrosterically stabilized (branched polyethylene imine (BPEI)-AgNPs)). The uncoated (H-2-ANPs), the citrate, and NaBH4-coated AgNPs aggregated at higher ionic strengths (100 mM NaNO3) and/or acidic pH (3.0). For these three nanomaterials, chloride (Cl-, 10 mM), as a background electrolyte, resulted in a minimal change in the hydrodynamic diameter even at low pH (3.0). This was limited by the presence of residual silver ions, which resulted in the formation of stable negatively charged AgCl colloids. Furthermore, the presence of Ca2+ (10 mM) resulted in aggregation of the three previously identified AgNPs regardless of the pH. As for PVP coated AgNPs, the ionic strength, pH and electrolyte type had no impact on the aggregation of the sterically stabilized AgNPs. The surface charge and aggregation of the BPEI coated AgNPs varied according to the solution pH.