Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Tópicos
de interesse
Detalhes

Detalhes

007
Publicações

2022

Analysis of the Relative Humidity Response of Hydrophilic Polymers for Optical Fiber Sensing

Autores
Dias, B; Carvalho, J; Mendes, JP; Almeida, JMMM; Coelho, LCC;

Publicação
POLYMERS

Abstract
Relative humidity (RH) monitorization is of extreme importance on scientific and industrial applications, and optical fiber sensors (OFS) may provide adequate solutions. Typically, these kinds of sensors depend on the usage of humidity responsive polymers, thus creating the need for the characterization of the optical and expansion properties of these materials. Four different polymers, namely poly(vinyl alcohol), poly(ethylene glycol), Hydromed™ D4 and microbiology agar were characterized and tested using two types of optical sensors. First, optical fiber Fabry–Perot (FP) tips were made, which allow the dynamical measurement of the polymers’ response to RH variations, in particular of refractive index, film thickness, and critical deliquescence RH. Using both FP tips and Long-Period fiber gratings, the polymers were then tested as RH sensors, allowing a comparison between the different polymers and the different OFS. For the case of the FP sensors, the PEG tips displayed excellent sensitivity above 80%RH, outperforming the other polymers. In the case of LPFGs, the 10% (wt/wt) PVA one displayed excellent sensitivity in a larger working range (60 to 100%RH), showing a valid alternative to lower RH environment sensing.

2022

A Plasmonic Biosensor Based on Light-Diffusing Fibers Functionalized with Molecularly Imprinted Nanoparticles for Ultralow Sensing of Proteins

Autores
Arcadio, F; Seggio, M; Del Prete, D; Buonanno, G; Mendes, J; Coelho, LCC; Jorge, PAS; Zeni, L; Bossi, AM; Cennamo, N;

Publicação
NANOMATERIALS

Abstract
Plasmonic bio/chemical sensing based on optical fibers combined with molecularly imprinted nanoparticles (nanoMIPs), which are polymeric receptors prepared by a template-assisted synthesis, has been demonstrated as a powerful method to attain ultra-low detection limits, particularly when exploiting soft nanoMIPs, which are known to deform upon analyte binding. This work presents the development of a surface plasmon resonance (SPR) sensor in silica light-diffusing fibers (LDFs) functionalized with a specific nanoMIP receptor, entailed for the recognition of the protein human serum transferrin (HTR). Despite their great versatility, to date only SPR-LFDs functionalized with antibodies have been reported. Here, the innovative combination of an SPR-LFD platform and nanoMIPs led to the development of a sensor with an ultra-low limit of detection (LOD), equal to about 4 fM, and selective for its target analyte HTR. It is worth noting that the SPR-LDF-nanoMIP sensor was mounted within a specially designed 3D-printed holder yielding a measurement cell suitable for a rapid and reliable setup, and easy for the scaling up of the measurements. Moreover, the fabrication process to realize the SPR platform is minimal, requiring only a metal deposition step.

2022

Study of LSPR Spectral Analysis Techniques on SPR Optical Fiber Sensors

Autores
Dos Santos, PSS; de Almeida, JMMM; Coelho, LCC;

Publicação
U.Porto Journal of Engineering

Abstract
Nanoparticles create localized surface plasmonic resonances (LSPR) with lower surrounding refractive index (SRI) sensitivities than their propagating SPR counterpart, originated in thin films. Historically, LSPR SRI sensitivities enhancements were achieved through spectral analysis methods that focus on unique spectral features. Herein, a study using that methodology was applied on SPR devices resulting in an increased sensitivity to SRI. It was found that by applying the inflection point method on optical fiber SPR sensors resulted in both sensitivity and resolution increments up to 44 and 35 %, respectively, in the SRI range from 1.3333 to 1.4150. Thus, successfully improving sensing capabilities of SPR based optical fiber sensors.

2022

Long-Period Fiber Gratings Coated with Poly(ethylene glycol) as Relative Humidity Sensors

Autores
Dias, B; de Almeida, JMMM; Coelho, LCC;

Publicação
U.Porto Journal of Engineering

Abstract
Relative humidity is an important parameter in controlled environments and is typically monitored using low-cost electrochemical sensors with low resolution and accuracy. This kind of sensors cannot not be implemented in harsh or explosive environments (as in pyrotechnic facilities) due to electrical discharges, or in marine structures where the oxidation of the sensing probe materials changes the sensing response). In these cases, fiber optic sensors can provide solutions due to their intrinsic properties, such as immunity to electromagnetic interference and resistance in harsh environments. This work presents preliminary results regarding the steps of the fabrication of Long-Period Fiber Gratings, the coating processes with a thin layer of poly(ethylene glycol) (PEG) and its sensing performance to relative humidity, displaying a from 60 to 100%sensitivity of 0.6 nm/%RH in the range of 80 to 100%RH.

2022

Simple Optical Fiber Interferometer for Dynamic Measurement of Refractive Index and Thickness of Polymer Films

Autores
Dias, B; Mendes, JPS; de Almeida, JMMM; Coelho, LCC;

Publicação
IEEE SENSORS JOURNAL

Abstract

Teses
supervisionadas

2020

Development of optical sensors for public health

Autor
Ana Beatriz Matias Teixeira

Instituição
IES_Outra

2020

Development of a hybrid CO2 monitoring system using spectral characteristics of a sensitive chemical membrane

Autor
Nuno Alexandre Pereira Mendes

Instituição
UP-FCUP

2020

Development of cost-effective monitoring systems for chemical water contamination using nanoparticle coated optical fibre sensors

Autor
Paulo Sérgio Soares dos Santos

Instituição
UP-FEUP

2018

Development of a low-cost interrogation system platform for corrosion sensors in offshore metallic structures

Autor
Paulo Sérgio Soares dos Santos

Instituição
UP-FCUP