title: Nanoporous TiO2/polyion thin-film-coated long-period grating sensors for the direct measurement of low-molecular-weight analytes.
abstract: We present novel nanoporous TiO(2)/polyion thin-film-coated long-period fiber grating (LPFG) sensors for the direct measurement of low-molecular-weight chemicals by monitoring the resonance wavelength shift. The hybrid overlay films are prepared by a simple layer-by-layer deposition approach, which is mainly based on the electrostatic interaction of TiO(2) nanoparticles and polyions. By the alternate immersion of LPFG into dispersions of TiO(2) nanoparticles and polyions, respectively, the so-formed TiO(2)/polyion thin film exhibits a unique nanoporous internal structure and has a relative higher refractive index than LPFG cladding. In particular, the porosity of the thin film reduces the diffusion coefficient and enhances the permeability retention of low-molecular-weight analytes within the porous film. The increases in the refractive index of the LPFG overlay results in a distinguished modulation of the resonance wavelength. Therefore, the detection sensitivity of LPFG sensors has been greatly improved, according to theoretical simulation. After the structure of the TiO(2)/polyion thin film was optimized, glucose solutions as an example with a low concentration of 10(-7) M was easily detected and monitored at room temperature.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China.
authors.forename: Rui-Zhu
authors.initials: RZ
authors.lastname: Yang
authors.forename: Wen-Fei
authors.initials: WF
authors.lastname: Dong
authors.forename: Xiang
authors.initials: X
authors.lastname: Meng
authors.forename: Xu-Lin
authors.initials: XL
authors.lastname: Zhang
authors.forename: Yun-Lu
authors.initials: YL
authors.lastname: Sun
authors.forename: Ya-Wei
authors.initials: YW
authors.lastname: Hao
authors.forename: Jing-Chun
authors.initials: JC
authors.lastname: Guo
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Zhang
authors.forename: Yong-Sen
authors.initials: YS
authors.lastname: Yu
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Song
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Qi
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Sun
mesh_terms: D005947:Glucose / Q000032:analysis*; D008970:Molecular Weight; D049329:Nanostructures / Q000737:chemistry*; D016062:Porosity; D012031:Refractometry; D012996:Solutions; D055672:Static Electricity; D020349:Surface Plasmon Resonance; D014025:Titanium / Q000737:chemistry*; D014867:Water
chemical_list: D012996:Solutions; D014867:Water; C009495:titanium dioxide; D014025:Titanium; D005947:Glucose