Straightforward, One-Step Synthesis of Alkanethiol-capped Silver Nanoparticles from an Aggregative Model of Growth
Straightforward, One-Step Synthesis of Alkanethiol-capped Silver Nanoparticles from an Aggregative Model of Growth
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DOI：
10.1021/la305133d
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发表时间：
2013-07-30
期刊：
影响因子：
3.9
通讯作者：
Green, David
中科院分区：
文献类型：
--
作者：
Farrell, Zachary;Shelton, Cameron;Green, David
应用经典成核理论和Derjaguin， Landau, Verwey, Overbeek （DLVO）胶体稳定性理论，研究了用硼氢化钠在乙醇中还原硝酸银合成DDT功能化纳米银的方法。这一分析表明，在本质上不稳定的初级颗粒上快速建立密集的滴滴涕配体刷以实现胶体稳定性的重要性。DLVO计算还表明，静电势对斥力相互作用的影响较小，这表明只要有足够的DDT在NP上形成密集的配体层，就可以在高离子强度的溶液中控制NP的大小和均匀性。这些见解被应用于设计一种新的直接，一步，一相合成生产烷硫醇功能化银NPs。为了验证DLVO理论的见解，在参数空间R = 3-12, S = 1-12，其中R = [NaBH4]/[AgNO3], S = [DDT]/[AgNO3], [AgNO3] = 10 mM中合成了16个样品。通常，R = 3或S = 1的样品是多分散的；而在R = 6 ~ 12和S = 3 ~ 12范围内，样品粒径均匀，平均粒径在3.5 ~ 4.7 nm之间。合成R = 72 ~ 108和S = 12的样品，测试粒子在高离子强度下的稳定性；同样，平均直径为3.5 ~ 3.8 nm的均匀NPs也被制备出来。最终，从DLVO理论中获得的见解成功地指导了一步一相技术的发展，该技术用于合成均匀的球形烷硫醇功能化银NPs。
Classical nucleation theory and Derjaguin, Landau, Verwey, Overbeek (DLVO) theory for colloidal stability were applied to gain insight into the synthesis of dodecanethiol (DDT) functionalized silver nanoparticles (NPs) by reduction of silver nitrate with sodium borohydride in ethanol. This analysis indicated the importance of quickly establishing a dense DDT ligand brush on inherently unstable primary particles to achieve colloidal stability. The DLVO calculations also indicated that the electrostatic potential was a minor contributor to repulsive interactions, signifying that it would be possible to control NP size and uniformity in solutions with high ionic strength, as long as sufficient DDT was available to form a densely packed ligand layer on the NPs. These insights were applied to design a new straightforward, one-step, one-phase synthesis for the production of alkanethiol-functionalized silver NPs. To test the insights from DLVO theory, 16 samples were synthesized in the parameter space R = 3-12, S = 1-12 where R = [NaBH4]/[AgNO3], S = [DDT]/[AgNO3], and [AgNO3] = 10 mM. In general, samples with R = 3 or S = 1 were polydisperse; however, samples in the R = 6-12 and S = 3-12 range had uniform particle sizes with average diameters between 3.5 and 4.7 nm. Additionally, samples with R = 72-108 and S = 12 were synthesized to test particle stability at high ionic strength; again, uniform NPs with average diameters from 3.5 to 3.8 nm were produced. Ultimately, the insights gained from DLVO theory successfully guided the development of a one-step, one-phase technique for the synthesis of uniform, spherical alkanethiol-functionalized silver NPs.