National Engineering Research Center for Colloidal Materials and School of Chemistry and Chemical Engineering , Shandong University , Ji'Nan 250100 , PR China.
Department of Chemistry , University of California , Riverside , California 92521 , United States.
Nano Lett. 2018 Aug 8;18(8):5312-5318. doi: 10.1021/acs.nanolett.8b02325. Epub 2018 Jul 20.
Dynamic manipulation of optical properties through the reversible assembly of plasmonic nanoparticles offers great opportunities for practical applications in many fields. The previous success, however, has been limited to Au nanoparticles. Reversible assembly and plasmonic tuning of Ag nanoparticles (AgNPs) have remained a significant challenge due to difficulty in finding an appropriate surface agent that can effectively stabilize the particle surface and control their interactions. Here, we overcome the challenge by developing a limited-ligand-protection (LLP) strategy for introducing poly(acrylic acid) with precisely controlled coverage to the AgNP surface to not only sufficiently stabilize the nanoparticles but also enable effective control over the surface charge and particle interaction through pH variation. The as-synthesized AgNPs can be reversibly assembled and disassembled and accordingly display broadly tunable coupling of plasmonic properties. Compared to the Au-based system, the success in the reversible assembly of AgNPs represents a significant step toward practical applications such as colorimetric pressure sensing because they offer many advantages, including broader spectral tuning range, higher color contrast, a one-pot process, and low materials and production cost. This work also highlights LLP as a new avenue for controlling the interparticle forces, their reversible assembly, and dynamic coupling of physical properties.
通过等离子体纳米粒子的可逆组装来动态操控光学性能，为许多领域的实际应用提供了巨大的机会。然而，之前的成功仅限于金纳米粒子。由于难以找到合适的表面活性剂来有效稳定颗粒表面并控制其相互作用，因此银纳米粒子（AgNPs）的可逆组装和等离子体调谐仍然是一个重大挑战。在这里，我们通过开发一种有限配体保护（LLP）策略来克服这一挑战，该策略用于将具有精确控制覆盖率的聚丙烯酸引入 AgNP 表面，不仅可以充分稳定纳米粒子，还可以通过 pH 值变化有效控制表面电荷和粒子相互作用。合成的 AgNPs 可以进行可逆组装和拆卸，从而显示出广泛可调的等离子体特性耦合。与基于 Au 的系统相比，AgNPs 可逆组装的成功是朝着实际应用迈出的重要一步，例如比色压力传感，因为它们具有许多优势，包括更宽的光谱调谐范围、更高的颜色对比度、一锅法和低材料及生产成本。这项工作还强调了 LLP 作为控制粒子间作用力、它们的可逆组装以及物理性质的动态耦合的新途径。
