Thermoresponsive Polymer Brush-Decorated 3-D Plasmonic Gold Nanorod Arrays as an Effective Plasmonic Sensing Platform

Abstract

Molecular sensing based on plasmonic materials is of great interest not only for basic scientific research but also for real-life applications. For plasmonic sensing, tunable hot-spot generation, in which the electromagnetic field is maximized, plays a key role. Herein, we developed a platform consisting of a thermoresponsive polymer brush with colloidal plasmonic particles and 3-D ordered/vertically aligned gold nanorod (AuNR) arrays for surface-enhanced Raman spectroscopy (SERS) applications. Poly(di(ethylene glycol) methyl ether methacrylate) brushes were synthesized via the interface-mediated reversible addition fragmentation chain transfer polymerization method. 3-D AuNR arrays were also fabricated by the oblique angle physical vapor deposition method. High-density hot-spot generation on the platforms was achieved by reducing the distance between the plasmonic particles and the underlying AuNR array as a result of phase transition of the polymer brushes. The design and optimization of such a platform will pave the way for molecular detection applications in a broad range of fields such as medicine, environmental protection, food safety, and homeland security.