Effects of polymer micelles of alkylated polyethylenimines on generation of gold nanoparticles
Effects of polymer micelles of alkylated polyethylenimines on generation of gold nanoparticles
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DOI：
10.1021/jp050136p
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发表时间：
2005-05-19
影响因子：
3.3
通讯作者：
Jao, MW
中科院分区：
文献类型：
--
作者：
Kuo, PL;Chen, CC;Jao, MW
通过开发聚乙烯亚胺(PEI)氨基的功能，合成了单烷基和双烷基聚乙烯亚胺(PEI-1R，PEI-2R)，并将其用作还原剂和稳定剂，这些稳定剂能够保护由四氯金酸(HAuCl4)生成的新生的金纳米颗粒。从染色聚合物的电子显微镜图像中可以清楚地看出，当由PEI-2R形成时，聚合物胶束是圆形的且结构良好，当由PEI-1R形成时，聚合物胶束是熔融的且结构较差，而当由PEI形成时，聚合物胶束是完全无结构的。这些发现与以芘为探针研究聚集行为的结果一致，其中荧光强度比(11113)为1.48PEI-2R形成的聚合物胶束比PEI-1R(I-1/I-3=1.64)和PEI(I-1/I-3=1.72)更紧密。使用高度烷基化的聚合物胶束(PEI-2R)可以最快地还原HAuCl4，并对生成的金纳米颗粒提供最有效的保护。当聚合物浓度高于胶束形成所需的浓度时，研究发现聚合物的疏水性对纳米粒子的形态有很大的影响，即使用PEI-2R时，生成的聚合物胶束被标记成完美的、圆形的项链状金纳米粒子，而使用PEI-1R时，生成的聚合物胶束标记的金纳米粒子不完美且圆形较少。当使用PEI时，这些结构完全不存在。烷基化PEI的使用，能够同时作为还原剂和非常有效的保护剂，极大地简化了制备金纳米颗粒的过程。
Mono- and di-alkylated polyethylenimines (PEI-1R, PEI-2R) were synthesized and used as both reductants, by exploiting the functionality of the polyethylenimine's (PEI) amino groups, and stabilizers able to protect nascent gold nanoparticles generated from hydrogen tetrachloroaurate (HAuCl4). From TEM images of the stained polymers, it is clear that the polymer micelles are round and well-structured when formed from PEI-2R, fused and less well-structured when formed from PEI-1R, and totally nonstructured when formed from PEI. These findings coincide with the results found by using pyrene as a probe to investigate aggregation behavior, where PEI-2R with a fluorescence intensity ratio (11113) of 1.48 forms the more closely packed polymer micelles than PEI-1R (I-1/I-3 = 1.64) and PEI (I-1/I-3 = 1.72). The use of the highly alkylated polymer micelle (PEI-2R) results in the fastest reduction of HAuCl4, and gives the most effective protection to the generated gold nanoparticles. When used at higher polymer concentrations than required for micelle formation, it was found that polymer hydrophobicity was highly influential in directing the nanoparticle's morphology, i.e., the resulting polymer micelles were labeled with perfect and round necklace-like gold nanoparticles when PEI-2R was used, and imperfect and less round gold nanoparticles when PEI-1R was employed. These structures were totally absent when PEI was used. The use of alkylated PEI, being able to act simultaneously as both a reductant and as a very effective protective agent, greatly simplifies the process used for preparing gold nanoparticles.