Abs tract In this work, a new optical device based on silver loaded electrospun nanofibers (ENFs)... more Abs tract In this work, a new optical device based on silver loaded electrospun nanofibers (ENFs) for measuring Relative Humidity is proposed. Fiber mats composed of poly(acrylic acid) and β-cyclodextrin were deposited onto an optical fiber core by electrospinning. Afterwards the ENFs were submitted to thermal curing. Then, the ENFs were loaded with Ag nanoparticles (Ag NPs) synthesized using a Ag + loa ding step and a further reduction step. Several load/reduction cycles were performed. Ag NPs enhance significantly the optical response of the polymer-only fiber mats. The Ag NPs loaded fiber was tested at variations of Relative Humidity (RH). The results showed a very fast response of the absorbance spectra enabling high performance applications such as human breathing monitoring.
desarrollo de estructuras de fbra óptica estrechada (taper) para la detección de vibraciones mecá... more desarrollo de estructuras de fbra óptica estrechada (taper) para la detección de vibraciones mecánicas development of tapered optical fibers structures (taper), to detect mechanical vibrations
In this paper, a new optical fiber humidity sensor based on PVdF nanowebs is presented. The elect... more In this paper, a new optical fiber humidity sensor based on PVdF nanowebs is presented. The electrospinning technique has been used to create a nanometric scale membrane onto the surface of a hollow core fiber (HCF). The fabricated sensor has demonstrated a repetitive response in the range from 50 to 70% of relative humidity with a rise time of 100 ms. Among other applications, this sensor is intended to be used for monitoring the human breathing. Therefore, high dynamic performances are required, especially in the higher relative humidity ranges.
This work presents an alternative approach for fabricating electrospun submicron highly hydrophil... more This work presents an alternative approach for fabricating electrospun submicron highly hydrophilic fiber mats loaded with silver nanoparticles. These fiber mats show a high efficient antibacterial behavior, very attractive for applications like wound healing and skin regeneration processes. The fabrication method is divided in two steps. First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD) submicron fibers were electrospun and further stabilized using a thermal treatment, yielding stable hydrogel-like fibers with diameters ranging from 100 nm up to several microns. In the second step, silver ions were loaded into the fibers and then reduced to silver nanoparticles in-situ. The electrospinning parameters were adjusted to achieve the desired properties of the fiber mat (density, size) and afterwards, the characteristics of the silver nanoparticles (amount, size, aggregation) were tuned by controlling the silver ion loading mechanism. Highly biocide surfaces were achieved showing more than 99.99% of killing efficiency. The two-step process improves the reproducibility and tunability of the fiber mats. To our knowledge, this is the first time that stable hydrogel fibers with a highly biocide behavior have been fabricated using electrospinning. V
Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industr... more Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industry using vibration analysis. Several techniques, mainly based on capacitive and piezoelectric accelerometers, have been applied for predictive maintenance. However, the negative influence of the electromagnetic interference (EMI) can be a real problem when electrical signals are used to detect and transmit physical parameters in noisy environments such as electric power generator plants with high levels of EMI. Optical fiber sensors are increasingly used because of the nonelectrical nature of signals. In this paper, the most frequently used vibration optical fiber sensors will be reviewed, classifying them by the sensing techniques and measurement principles. The main techniques, intensity modulation, fiber bragg gratings and Fabry-Pérot Interferometry, will be reviewed here.
Abs tract In this work, a new optical device based on silver loaded electrospun nanofibers (ENFs)... more Abs tract In this work, a new optical device based on silver loaded electrospun nanofibers (ENFs) for measuring Relative Humidity is proposed. Fiber mats composed of poly(acrylic acid) and β-cyclodextrin were deposited onto an optical fiber core by electrospinning. Afterwards the ENFs were submitted to thermal curing. Then, the ENFs were loaded with Ag nanoparticles (Ag NPs) synthesized using a Ag + loa ding step and a further reduction step. Several load/reduction cycles were performed. Ag NPs enhance significantly the optical response of the polymer-only fiber mats. The Ag NPs loaded fiber was tested at variations of Relative Humidity (RH). The results showed a very fast response of the absorbance spectra enabling high performance applications such as human breathing monitoring.
desarrollo de estructuras de fbra óptica estrechada (taper) para la detección de vibraciones mecá... more desarrollo de estructuras de fbra óptica estrechada (taper) para la detección de vibraciones mecánicas development of tapered optical fibers structures (taper), to detect mechanical vibrations
In this paper, a new optical fiber humidity sensor based on PVdF nanowebs is presented. The elect... more In this paper, a new optical fiber humidity sensor based on PVdF nanowebs is presented. The electrospinning technique has been used to create a nanometric scale membrane onto the surface of a hollow core fiber (HCF). The fabricated sensor has demonstrated a repetitive response in the range from 50 to 70% of relative humidity with a rise time of 100 ms. Among other applications, this sensor is intended to be used for monitoring the human breathing. Therefore, high dynamic performances are required, especially in the higher relative humidity ranges.
This work presents an alternative approach for fabricating electrospun submicron highly hydrophil... more This work presents an alternative approach for fabricating electrospun submicron highly hydrophilic fiber mats loaded with silver nanoparticles. These fiber mats show a high efficient antibacterial behavior, very attractive for applications like wound healing and skin regeneration processes. The fabrication method is divided in two steps. First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD) submicron fibers were electrospun and further stabilized using a thermal treatment, yielding stable hydrogel-like fibers with diameters ranging from 100 nm up to several microns. In the second step, silver ions were loaded into the fibers and then reduced to silver nanoparticles in-situ. The electrospinning parameters were adjusted to achieve the desired properties of the fiber mat (density, size) and afterwards, the characteristics of the silver nanoparticles (amount, size, aggregation) were tuned by controlling the silver ion loading mechanism. Highly biocide surfaces were achieved showing more than 99.99% of killing efficiency. The two-step process improves the reproducibility and tunability of the fiber mats. To our knowledge, this is the first time that stable hydrogel fibers with a highly biocide behavior have been fabricated using electrospinning. V
Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industr... more Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industry using vibration analysis. Several techniques, mainly based on capacitive and piezoelectric accelerometers, have been applied for predictive maintenance. However, the negative influence of the electromagnetic interference (EMI) can be a real problem when electrical signals are used to detect and transmit physical parameters in noisy environments such as electric power generator plants with high levels of EMI. Optical fiber sensors are increasingly used because of the nonelectrical nature of signals. In this paper, the most frequently used vibration optical fiber sensors will be reviewed, classifying them by the sensing techniques and measurement principles. The main techniques, intensity modulation, fiber bragg gratings and Fabry-Pérot Interferometry, will be reviewed here.
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