Thermoresponsive chiral plasmonic nanoparticles

Yiyi Liu, Tharaka Perera, Qianqian Shi, Zijun Yong, Sudaraka Mallawaarachchi, Bo Fan, Julia Ann-Therese Walker, Christopher J. Lupton, San H. Thang, Malin Premaratne, Wenlong Cheng

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Chiral metallic nanoparticles can exhibit novel plasmonic circular dichroism (PCD) in the ultraviolet and visible range of the electromagnetic spectrum. Here, we investigate how thermoresponsive dielectric nanoenvironments will influence such PCD responses through poly(N-isopropylacrylamide) (PNIPAM) modified chiral gold nanorods (AuNRs). We observed the temperature-dependent chiral plasmonic responses distinctly from unmodified counterparts. As for the modified systems, the PCD peaks for both l-AuNRs and d-AuNRs at 50 °C red shifted simultaneously with enhanced intensities compared to the results at 20 °C. In contrast, the unmodified l-AuNRs and d-AuNRs exhibited no peak shift with reduced intensities. Subsequent simulation and experimental studies demonstrated that the enhanced PCD was attributed to PNIPAM chain collapse causing the increase of the refractive index by expelling minute water out of the corona surrounding chiral plasmonic AuNRs. Notably, such thermoresponsive chiral plasmonic responses are reversible, general, and extendable to other types of chiral plasmonic nanoparticles.

Original languageEnglish
Pages (from-to)4292-4303
Number of pages12
JournalNanoscale
Volume14
DOIs
Publication statusPublished - 17 Feb 2022

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