Localized surface plasmon resonance gas sensor of Au nano-islands coated with molecularly imprinted polymer: Influence of polymer thickness on sensitivity and selectivity

alpha-Pinene is a kind of biomarker vapors emitted by plant during metabolism process. In this work, A localized surface plasmon resonance (LSPR) sensors based on the large and closely-packed Au nano-islands were propose to be coupled with the molecularly imprinted polymer (MIP) film for alpha-pinene vapor detection. Au nano-island film was prepared through repeated Au sputtering and annealing with cycles as many as 18. MIP alpha pinene was prepared using methacylic acid as monomer, ethylene glycol dimethylacrylate as cross-linker, and alpha-pinene as the template molecule. Pre-polymerized MIP alpha pinene solution was spin-coated on Au nano-island films at a series of speeds. The influence of spin coating speed on polymer thickness and target vapor binding capability was investigated. The result demonstrated that thick polymer layer could bind more template molecules than the thin one, which verified our speculation that there were more specific template binding sites in thick polymer layer. In addition, the in-situ response of coated Au nano-island film to alpha-pinene vapor was verified to be rapid (in less than 10 s) and reversible. The selective alpha-pinene vapor adsorption and absorption characteristics of MIP alpha pinene coated Au nano-islands film to alpha-pinene vapor was observed comparing with the responses to gamma-terpinene and limonene vapors. (C) 2016 Elsevier B.V. All rights reserved.