Kitamura Shoma, Iijima Motoyuki, Tatami Junichi, Fuke Tsubasa, Hinotsu Takashi, Sato Kimitaka
Graduate School of Engineering Science, Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, Kanagawa 240-8501, Japan.
Faculty of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogayaku, Yokohama, Kanagawa 240-8501, Japan.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13705-13713. doi: 10.1021/acsami.1c00629. Epub 2021 Mar 14.
Ag nanowire suspensions are one of the indispensable materials in the design and fabrication of flexible transparent conductive films. Although the required properties of Ag nanowire films, such as their high transparency, low haze, low contact resistance, and suppression of yellowing, are strongly related to the nanowire surface phenomena, approaches for the surface modification of polyol-synthesized Ag nanowires have rarely been reported. Here, we report the design of a polymer ligand and surface modification of Ag nanowires with the designed polymer to obtain color-tunable transparent conductive films through a simple casting and drying process. In this approach, we synthesized a series of functional polymer ligands by partially grafting polyethyleneimine (PEI) with polyethylene glycol (PEG) chains (PEI-mPEG). The amine sites in PEI-mPEG were designed to act as adsorption sites as well as anchoring sites for an anionic blue dye for suppressing the yellow color tone of Ag nanowires. On the other hand, the PEG chains were designed to maintain the stability of the Ag nanowires in aqueous suspensions and to suppress corrosion of Ag nanowires, which is enhanced by the amine groups of PEI. The effect of the grafting ratio of PEG chains on PEI on the ligand-exchange behavior of the Ag nanowires, their dispersion stability in aqueous inks, and final film properties were investigated systematically. Furthermore, successful color tuning of the Ag nanowire film, without suppressing the conductive and optical properties, is demonstrated by loading anionic blue dye onto PEI-mPEG-modified Ag nanowires.
银纳米线悬浮液是柔性透明导电薄膜设计与制造中不可或缺的材料之一。尽管银纳米线薄膜所需的性能，如高透明度、低雾度、低接触电阻和抑制泛黄等，与纳米线表面现象密切相关，但关于多元醇合成的银纳米线表面改性方法的报道却很少。在此，我们报告了一种聚合物配体的设计以及用所设计的聚合物对银纳米线进行表面改性，通过简单的浇铸和干燥工艺获得颜色可调的透明导电薄膜。在这种方法中，我们通过将聚乙二醇（PEG）链部分接枝到聚乙烯亚胺（PEI）上合成了一系列功能性聚合物配体（PEI - mPEG）。PEI - mPEG中的胺基位点被设计为作为阴离子蓝色染料的吸附位点以及锚定位点，用于抑制银纳米线的黄色调。另一方面，PEG链被设计用于维持银纳米线在水性悬浮液中的稳定性，并抑制银纳米线的腐蚀，而PEI的胺基会增强这种腐蚀。系统地研究了PEI上PEG链的接枝比例对银纳米线的配体交换行为、它们在水性油墨中的分散稳定性以及最终薄膜性能的影响。此外，通过将阴离子蓝色染料负载到PEI - mPEG改性的银纳米线上，证明了在不抑制导电和光学性能的情况下成功实现了银纳米线薄膜的颜色调节。
