调节热响应性等离子体纳米凝胶光学性质的简单方法

Simple Method for Tuning the Optical Properties of Thermoresponsive Plasmonic Nanogels.

作者信息

Han Fei, Soeriyadi Alexander H, Vivekchand S R C, Gooding J Justin

机构信息

School of Chemistry, ‡Australian Centre for NanoMedicine, and §ARC Center of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales, Sydney, New South Wales 2052, Australia.

School of Chemistry, Australian Centre for NanoMedicine, and §ARC Center of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales, Sydney, New South Wales 2052, Australia.

出版信息

ACS Macro Lett. 2016 May 17;5(5):626-630. doi: 10.1021/acsmacrolett.6b00222. Epub 2016 May 4.

DOI:10.1021/acsmacrolett.6b00222

PMID:35632384

Abstract

We report a straightforward way for forming and tuning the optical properties of thermally responsive plasmonic nanogels. Upon functionalization, a small red shift (2-3 nm) of the pNIPAM@AuNPs was observed due to changes in the refractive index surrounding the AuNP. By adding thermoresponsive poly--isopropylacrylamide (pNIPAM) into the pNIPAM@AuNP, its optical response was significantly increased. Heating the nanogel such that the pNIPAM collapsed and acted as a cross-link resulted in the aggregation of the AuNPs. The plasmonic response with red shifts of up to 20 nm was observed. The enlarged red shift was due to the increase in the dielectric constant around the particles and the interparticle interaction of the AuNPs. The interparticle interaction also leads to the broadening of the spectra. Experimental data and finite-difference time-domain (FDTD) calculation are in agreement with this observation. The temperature-dependent optical properties were reversible through multiple cycles of heating and cooling.

摘要

我们报道了一种形成和调节热响应性等离子体纳米凝胶光学性质的直接方法。功能化后，由于金纳米颗粒周围折射率的变化，观察到聚N-异丙基丙烯酰胺@金纳米颗粒（pNIPAM@AuNPs）有一个小的红移（2 - 3纳米）。通过向pNIPAM@AuNP中加入热响应性聚N-异丙基丙烯酰胺（pNIPAM），其光学响应显著增强。加热纳米凝胶使pNIPAM塌陷并起到交联作用，导致金纳米颗粒聚集。观察到等离子体响应有高达20纳米的红移。红移增大是由于颗粒周围介电常数的增加以及金纳米颗粒之间的相互作用。颗粒间相互作用还导致光谱展宽。实验数据和时域有限差分（FDTD）计算与这一观察结果一致。通过多次加热和冷却循环，温度依赖的光学性质是可逆的。