Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, MO 63130, USA.
Nanotechnology. 2012 Jun 29;23(25):255502. doi: 10.1088/0957-4484/23/25/255502. Epub 2012 May 31.
In this work, we demonstrate that plasmonic nanostructures can be employed as nanoscale transducers to monitor the growth and phase transitions in ultrathin polymer films. In particular, gold nanorods with high refractive index sensitivity (~150 nm/refractive index unit (RIU)) were employed to probe the growth and swelling of polyelectrolyte multilayers (PEM). By comparing the wavelength shift and extinction intensity increase of the localized surface plasmon resonance (LSPR) of the gold nanorods coated with PEM in air and water, the swelling of PEM was estimated to be 26% ± 6%. The swelling was quantitatively confirmed with independent thickness measurement of PEM in dry and swollen states using AFM. The deployment of shape-controlled metal nanostructures with high refractive index sensitivity represents a novel and facile approach for monitoring the phase transition in polymers with nanoscale resolution.
在这项工作中，我们证明了等离子体纳米结构可以作为纳米级传感器，用于监测超薄聚合物薄膜中的生长和相转变。具体来说，我们使用具有高折射率灵敏度（~150nm/折射率单位（RIU））的金纳米棒来探测聚电解质多层（PEM）的生长和溶胀。通过比较在空气和水中涂有 PEM 的金纳米棒的局域表面等离子体共振（LSPR）的波长位移和消光强度增加，估计 PEM 的溶胀为 26%±6%。通过使用 AFM 在干燥和溶胀状态下对 PEM 进行独立的厚度测量，对溶胀进行了定量确认。具有高折射率灵敏度的形状可控金属纳米结构的应用代表了一种新颖而简单的方法，可用于以纳米级分辨率监测聚合物中的相转变。
