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In Situ Studies of Surface‐Plasmon‐Resonance‐Coupling Sensor Mediated by Stimuli‐Sensitive Polymer Linker
Author(s) -
Lee JiEun,
Chung Kyungwha,
Lee Jumi,
Shin Kwanwoo,
Kim Dong Ha
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201503340
Subject(s) - materials science , surface plasmon resonance , plasmon , polymer , linker , poly(n isopropylacrylamide) , colloidal gold , layer (electronics) , in situ , nanoparticle , refractive index , coupling (piping) , chemical engineering , nanotechnology , optoelectronics , composite material , copolymer , organic chemistry , chemistry , computer science , operating system , engineering
Hybrid plasmonic nanostructures comprising gold nanoparticle (AuNP) arrays separated from Au substrate through a temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPAM) linker layer are constructed, and unique plasmonic‐coupling‐based surface plasmon resonance (SPR) sensing properties are investigated. The optical properties of the model system are investigated by in situ and scan‐mode SPR analysis. The swelling‐shrinking transitions in the polymer linker brush are studied by in situ contact‐mode atomic force microscopy at two different temperatures in water. It is revealed that the thickness of the PNIPAM layer is decreased from 30 to 14 nm by increasing the temperature from 20 to 32 °C. For the first time the dependence of the coupling behavior in AuNPs is investigated with controlled density on the temperature in a quantitative manner in terms of the change in SPR signals. The device containing AuNPs with optimized AuNP density shows 3.2‐times enhanced sensitivity compared with the control Au film‐PNIPAM sample. The refractive index sensing performance of the Au film‐PNIPAM‐AuNPs is greater than that of Au film‐PNIPAM by 19% when the PNIPAM chains have a collapsed conformation above lower critical solution temperature.