Arjen Boersma | TNO - Academia.edu (original) (raw)

Papers by Arjen Boersma

Research paper thumbnail of Dielectric Analysis of the Breakup of Liquid Crystalline Polymer Fibers in a Thermoplastic Matrix

Macromolecules, 1997

In this paper we discuss the use of dielectric spectroscopy as a means to study the morphology of... more In this paper we discuss the use of dielectric spectroscopy as a means to study the morphology of polymer blends. We have investigated a model system of thermotropic liquid crystalline polymer (Vectra B950) fibers lined up in a polypropylene (Stamylan P 13E10) matrix. The appearance of interfacial polarization at the interface between the two polymeric phases makes it possible to calculate the shape of the inclusions. For this purpose a formula is derived, which gives the shape factor of a distorted fiber as a function of the distortion amplitude. The calculated shapes of the fibers agree very well with the actual shapes, despite the approximations made. The agreement was proven by performing dielectric measurements under an optical microscope. As expected, the growth rate of thick fibers is smaller than that of thinner ones. A comparison between experiments under the microscope and in a dielectric sample holder showed the importance of the heating rate on the breakup of the fibers.

Research paper thumbnail of Dielectric on-line spectroscopy during extrusion of polymer blends

Polymer, 1999

Dielectric spectroscopy is a technique which is still hardly used for on-line characterization of... more Dielectric spectroscopy is a technique which is still hardly used for on-line characterization of polymers. In this article we describe its use at medium frequencies (between 10Hz and 1MHz) for on-line monitoring of the morphology of polymer blends during extrusion. A sheet extrusion die containing two electrodes, made it possible to perform the dielectric on-line analysis.A blend of a thermotropic

Research paper thumbnail of Interfacial tension between a liquid crystalline polyesteramide and polypropylene obtained by dielectric spectroscopy

J Polym Sci B Polym Phys, 1998

Dielectric spectroscopy is an unexplored technique in the elucidation of the morphology of polyme... more Dielectric spectroscopy is an unexplored technique in the elucidation of the morphology of polymer blends. Especially the appearance of interfacial polarization can reveal important information about the microstructure of a polymer blend. A model system of liquid crystalline polymer fibers lined up in a thermoplastic matrix was investigated. After heating above the melting temperature of both phases, the fibers developed distortions which grew with time. Dielectric spectroscopy was used to follow the change in shape of the distorted fibers. The use of only two frequencies made it possible to increase the number of relevant data points in the initial stages of the fiber breakup process. From these measurements it was possible to calculate the growth rate and hence the interfacial tension between the two polymers.

Research paper thumbnail of Characterization of Spirooxazine and Spiropyran Hosted in Poly(Methyl Methacrylate) for Germicidal UV Source Indicator Application

Optics and Photonics Journal, 2013

A characterization of photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'... more A characterization of photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtha[2,1-b] [1,4]oxazine] (spirooxazine) and 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] (spiropyran) compounds hosted in poly(methyl methacrylate) (PMMA) was carried out. The parameters which influenced the photochromic behavior of both compounds were investigated. After ultraviolet (UV) irradiation, it was demonstrated that the temperature was the dominant factor which influenced the deactivation of both materials. For spiropyran, it was demonstrated that the process could be photo-induced with a certain wavelength which we have specified in this manuscript. It was also found that X-Ray did not affect the photo physical properties of spirooxazine and spiropyran. Finally, both materials could be used as low-cost germicidal UV indicators.

Research paper thumbnail of Encapsulation by interfacial polycondensation. I. The capsule production and a model for wall growth

Journal of Membrane Science, 1992

... membrane produced exists of a top-layer and a sub-layer as in asymmetrical membranes A model ... more ... membrane produced exists of a top-layer and a sub-layer as in asymmetrical membranes A model ... of TDC inside the capsule with time, is presented For a spherical capsule the model ... pores, whose walls are formed around droplets at the organic side of the membrane The pore ...

Research paper thumbnail of Dielectric study on size effects in polymer laminates and blends

J Polym Sci B Polym Phys, 1998

In this article we will focus on the dielectric properties of laminates and blends of a partially... more In this article we will focus on the dielectric properties of laminates and blends of a partially conducting (the liquid crystalline copolyesteramide Vectra B950) and an insulating (polypropylene or mica) phase. Dielectric spectroscopy was used as a tool to obtain information about the influence of the dimensions of the conducting phase in these laminates and blends. With decreasing thickness of the conducting layer in the laminates, the measured permittivities deviate more and more from the values predicted using conventional dielectric mixture models. From this discrepancy it is possible to calculate the thickness of the charge layer (ϭDebye length) in the conducting phase and the thickness of this phase itself, using a model derived by Trukhan. This model incorporates not only conduction, but also diffusion of the charges. Similar experiments were performed on a system of Vectra B950 particles in a polypropylene matrix. After the derivation of a new model, which combines the Trukhan model for space charges with the Böttcher equation for dielectric mixtures, we could make a distinction between samples containing large and small particles. For samples containing small particles, it is even possible to determine the variation in particle sizes. However, the use of a Debye length of 1.1 m obtained from the laminates resulted in particle sizes that were two times higher than the actual values.

Research paper thumbnail of Mobility and solubility of antioxidants and oxygen in glassy polymers. I. Concentration and temperature dependence of antioxidant sorption

Journal of Applied Polymer Science, Aug 22, 2003

The mobility of small molecules in a glassy polymer is largely determined by the amount of free v... more The mobility of small molecules in a glassy polymer is largely determined by the amount of free volume present in the material. The amount of free volume can be altered by changing the physical state of the polymer. Physical ageing reduces this amount, whereas the thermal rejuvenation increases it. The change in free volume was monitored by oxygen permeation and antioxidant sorption experiments. A clear correlation was found between the physical ageing on the one hand and oxygen permeability on the other. Since the mobility of antioxidants and oxygen are important parameters for the stabilisation of a polymer against oxidation, the physical state of the polymer can have a significant influence on the service life of the product. #

Research paper thumbnail of Distributed optical chemical sensor

Research paper thumbnail of A dielectric study on the microstructure in polymers and blends. Orientatien, crystallization and interfacial phenomena in a liquid crystalline polymer and its blends

Research paper thumbnail of On-line dielectric measuring device for multi phase system, especially polymer melt or solution, contains processor for measuring complex permittivity as a function of electric field frequencies

Research paper thumbnail of Process for producing biopolymer nanoparticles

Research paper thumbnail of Coated waveguide for optical detection

Research paper thumbnail of Multi-level single mode 2D polymer waveguide optical interconnects using nano-imprint lithography

Optics express, 2015

Single and multi-layer passive optical interconnects using single mode polymer waveguides are dem... more Single and multi-layer passive optical interconnects using single mode polymer waveguides are demonstrated using UV nano-imprint lithography. The fabrication tolerances associated with imprint lithography are investigated and we show a way to experimentally quantify a small variation in index contrast between core and cladding of fabricated devices. 1x2 splitting devices based on directional couplers and multimode interference interferometers are demonstrated to have less than 0.45 dB insertion loss with 0.02 ± 0.01 dB power imbalance between the outputs. We demonstrate an 'optical via' with an insertion loss less than 0.45 dB to transfer light from one optical signal plane to another. A 1x4 two-dimensional optical port is experimentally demonstrated to spatially split the input power with an insertion loss of 1.2 dB.

Research paper thumbnail of Optical coupling structure made by imprinting between single-mode polymer waveguide and embedded VCSEL

Optical Interconnects XV, 2015

Polymer-based integrated optics is attractive for inter-chip optical interconnection applications... more Polymer-based integrated optics is attractive for inter-chip optical interconnection applications, for instance, for coupling photonic devices to fibers in high density packaging. In such a hybrid integration scheme, a key challenge is to achieve efficient optical coupling between the photonic chips and waveguides. With the single-mode polymer waveguides, the alignment tolerances become especially critical as compared to the typical accuracies of the patterning processes. We study novel techniques for such coupling requirements. In this paper, we present a waveguide-embedded micro-mirror structure, which can be aligned with high precision, even active alignment method is possible. The structure enables 90 degree bend coupling between a single-mode waveguide and a vertical-emitting/detecting chip, such as, a VCSEL or photodiode, which is embedded under the waveguide layer. Both the mirror structure and low-loss polymer waveguides are fabricated in a process based mainly on the direct-pattern UV nanoimprinting technology and on the use of UVcurable polymeric materials. Fabrication results of the coupling structure with waveguides are presented, and the critical alignment tolerances and manufacturability issues are discussed. Proc. of SPIE Vol. 9368 93680H-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 04/29/2015 Terms of Use: http://spiedl.org/terms

Research paper thumbnail of Average particle size in polymer blends obtained by dielectric spectroscopy

10th International Symposium on Electrets (ISE 10). Proceedings (Cat. No.99 CH36256), 1999

Previously we focussed on the dielectric properties of laminates and blends consisting of a weakl... more Previously we focussed on the dielectric properties of laminates and blends consisting of a weakly conducting and an insulating phase. Dielectric spectroscopy was used as a tool to obtain information about the dimensions of the conducting phase. With decreasing thickness of the conducting layer in the laminates, the permittivities measured were found to deviate more and more from those predicted

Research paper thumbnail of Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material

Optical Sensing and Detection III, 2014

ABSTRACT This paper describes experimental measurement results for photonic crystal sensor device... more ABSTRACT This paper describes experimental measurement results for photonic crystal sensor devices which have been functionalized for gas sensing applications. The sensor consists of a two dimensional photonic crystal etched into a slab waveguide having a refractive index of 1.7-1.9. Test devices were fabricated from SiON material on silicon / silicon dioxide platform, and also in polymer materials on silicon platform. The inorganic photonic crystals were made using direct write electron-beam lithography and reactive ion etching. The polymeric devices were made by nano-imprint lithography using the SiON structure as the imprint master. The high refractive index polymer was composed of a TiO2 - UV resin nanocomposite having a nanoparticle fraction between 50 and 60 wt%. This resulted in a tunable refractive index between 1.7 and 1.85. Devices were functionalized for gas sensing applications by coating the surface with a chemical receptor. This responsive layer reacts with the target gas and changes its refractive index. This change causes the angle of out-coupling to change slightly. In this paper we report successful detection of formaldehyde in air at sub ppm levels, and discuss details of chemical functionalization of the PC sensor.

Research paper thumbnail of Toward large-area roll-to-roll printed nanophotonic sensors

Optical Sensing and Detection III, 2014

ABSTRACT Polymers have become an important material group in fabricating discrete photonic compon... more ABSTRACT Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular imprint (MIP) functionalization methods were applied in the sensor demonstrators. In this paper, the process flow in fabricating large-area nanophotonic structures by the use of sheet-level and roll-to-roll UV- nanoimprinting is reported.

Research paper thumbnail of Coating based fiber Bragg grating humidity sensor array

OFS2012 22nd International Conference on Optical Fiber Sensors, 2012

Research paper thumbnail of Polymer-based optical interconnects using nanoimprint lithography

Optoelectronic Interconnects XIII, 2013

ABSTRACT The increasing request for higher data speeds in the information and communication techn... more ABSTRACT The increasing request for higher data speeds in the information and communication technology leads to continuously increasing performance of microprocessors. This has led to the introduction of optical data transmission as a replacement of electronic data transmission in most transmission applications longer than 10 meters. However, a need remains for optical data transmission for shorter distances inside the computer. This paper gives an overview of the Joint European project FIREFLY, in which new polymer based single mode waveguides are developed for integration with VCSELs, splitters and fibers that will be manufactured using multi-layer nanoimprint lithography (NIL). Innovative polymers, new applications of nano-technology, new methods for optical coupling between components, and the integration of all these new components are the technical ingredients of this ambitious project.

Research paper thumbnail of Solid-state potentiometric biosensors for pH quantification in biological samples

2011 IEEE SENSORS Proceedings, 2011

This paper reports on manufacturing and characterization of an all-solid-state potentiometric sen... more This paper reports on manufacturing and characterization of an all-solid-state potentiometric sensor aimed at monitoring pH in dialysate or blood plasma for patients who undergo dialysis. The sensing polymer-based membrane, coated on top of the Au working electrodes, contains a polymer matrix - poly(vinyl chloride), octadecyl isonicotinate as sensor molecule, plasticizer bis(2-ethyl hexyl) sebacate, and potassium-tetrakis(4-chlorophenyl) borate. The sensor was first calibrated over a wider pH interval, i.e. 5.0 – 9.0, and then for a pH interval which overlaps with the physiological pH, i.e. 7.0 – 8.0, followed by tests in human blood plasma. The response of the sensor is linear over the studied pH range, with a lifetime of two weeks and an accuracy of ∼ 0.08 pH. The response of the sensor is influenced by the storage conditions, and tests with sensors stored dry prior to potential measurements in buffers show that the sensor needs a few hours to reach an equilibrium, as opposed to seconds for the sensors stored in pH buffers prior to data collection. Monitoring the potential for 18 h continuously shows that the sensor does not drift. Toxicity and leaching of components from the sensor membrane into the liquid environment around it were studied, and determined which components were selected to further develop the pH sensor.

Research paper thumbnail of Dielectric Analysis of the Breakup of Liquid Crystalline Polymer Fibers in a Thermoplastic Matrix

Macromolecules, 1997

In this paper we discuss the use of dielectric spectroscopy as a means to study the morphology of... more In this paper we discuss the use of dielectric spectroscopy as a means to study the morphology of polymer blends. We have investigated a model system of thermotropic liquid crystalline polymer (Vectra B950) fibers lined up in a polypropylene (Stamylan P 13E10) matrix. The appearance of interfacial polarization at the interface between the two polymeric phases makes it possible to calculate the shape of the inclusions. For this purpose a formula is derived, which gives the shape factor of a distorted fiber as a function of the distortion amplitude. The calculated shapes of the fibers agree very well with the actual shapes, despite the approximations made. The agreement was proven by performing dielectric measurements under an optical microscope. As expected, the growth rate of thick fibers is smaller than that of thinner ones. A comparison between experiments under the microscope and in a dielectric sample holder showed the importance of the heating rate on the breakup of the fibers.

Research paper thumbnail of Dielectric on-line spectroscopy during extrusion of polymer blends

Polymer, 1999

Dielectric spectroscopy is a technique which is still hardly used for on-line characterization of... more Dielectric spectroscopy is a technique which is still hardly used for on-line characterization of polymers. In this article we describe its use at medium frequencies (between 10Hz and 1MHz) for on-line monitoring of the morphology of polymer blends during extrusion. A sheet extrusion die containing two electrodes, made it possible to perform the dielectric on-line analysis.A blend of a thermotropic

Research paper thumbnail of Interfacial tension between a liquid crystalline polyesteramide and polypropylene obtained by dielectric spectroscopy

J Polym Sci B Polym Phys, 1998

Dielectric spectroscopy is an unexplored technique in the elucidation of the morphology of polyme... more Dielectric spectroscopy is an unexplored technique in the elucidation of the morphology of polymer blends. Especially the appearance of interfacial polarization can reveal important information about the microstructure of a polymer blend. A model system of liquid crystalline polymer fibers lined up in a thermoplastic matrix was investigated. After heating above the melting temperature of both phases, the fibers developed distortions which grew with time. Dielectric spectroscopy was used to follow the change in shape of the distorted fibers. The use of only two frequencies made it possible to increase the number of relevant data points in the initial stages of the fiber breakup process. From these measurements it was possible to calculate the growth rate and hence the interfacial tension between the two polymers.

Research paper thumbnail of Characterization of Spirooxazine and Spiropyran Hosted in Poly(Methyl Methacrylate) for Germicidal UV Source Indicator Application

Optics and Photonics Journal, 2013

A characterization of photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'... more A characterization of photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtha[2,1-b] [1,4]oxazine] (spirooxazine) and 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] (spiropyran) compounds hosted in poly(methyl methacrylate) (PMMA) was carried out. The parameters which influenced the photochromic behavior of both compounds were investigated. After ultraviolet (UV) irradiation, it was demonstrated that the temperature was the dominant factor which influenced the deactivation of both materials. For spiropyran, it was demonstrated that the process could be photo-induced with a certain wavelength which we have specified in this manuscript. It was also found that X-Ray did not affect the photo physical properties of spirooxazine and spiropyran. Finally, both materials could be used as low-cost germicidal UV indicators.

Research paper thumbnail of Encapsulation by interfacial polycondensation. I. The capsule production and a model for wall growth

Journal of Membrane Science, 1992

... membrane produced exists of a top-layer and a sub-layer as in asymmetrical membranes A model ... more ... membrane produced exists of a top-layer and a sub-layer as in asymmetrical membranes A model ... of TDC inside the capsule with time, is presented For a spherical capsule the model ... pores, whose walls are formed around droplets at the organic side of the membrane The pore ...

Research paper thumbnail of Dielectric study on size effects in polymer laminates and blends

J Polym Sci B Polym Phys, 1998

In this article we will focus on the dielectric properties of laminates and blends of a partially... more In this article we will focus on the dielectric properties of laminates and blends of a partially conducting (the liquid crystalline copolyesteramide Vectra B950) and an insulating (polypropylene or mica) phase. Dielectric spectroscopy was used as a tool to obtain information about the influence of the dimensions of the conducting phase in these laminates and blends. With decreasing thickness of the conducting layer in the laminates, the measured permittivities deviate more and more from the values predicted using conventional dielectric mixture models. From this discrepancy it is possible to calculate the thickness of the charge layer (ϭDebye length) in the conducting phase and the thickness of this phase itself, using a model derived by Trukhan. This model incorporates not only conduction, but also diffusion of the charges. Similar experiments were performed on a system of Vectra B950 particles in a polypropylene matrix. After the derivation of a new model, which combines the Trukhan model for space charges with the Böttcher equation for dielectric mixtures, we could make a distinction between samples containing large and small particles. For samples containing small particles, it is even possible to determine the variation in particle sizes. However, the use of a Debye length of 1.1 m obtained from the laminates resulted in particle sizes that were two times higher than the actual values.

Research paper thumbnail of Mobility and solubility of antioxidants and oxygen in glassy polymers. I. Concentration and temperature dependence of antioxidant sorption

Journal of Applied Polymer Science, Aug 22, 2003

The mobility of small molecules in a glassy polymer is largely determined by the amount of free v... more The mobility of small molecules in a glassy polymer is largely determined by the amount of free volume present in the material. The amount of free volume can be altered by changing the physical state of the polymer. Physical ageing reduces this amount, whereas the thermal rejuvenation increases it. The change in free volume was monitored by oxygen permeation and antioxidant sorption experiments. A clear correlation was found between the physical ageing on the one hand and oxygen permeability on the other. Since the mobility of antioxidants and oxygen are important parameters for the stabilisation of a polymer against oxidation, the physical state of the polymer can have a significant influence on the service life of the product. #

Research paper thumbnail of Distributed optical chemical sensor

Research paper thumbnail of A dielectric study on the microstructure in polymers and blends. Orientatien, crystallization and interfacial phenomena in a liquid crystalline polymer and its blends

Research paper thumbnail of On-line dielectric measuring device for multi phase system, especially polymer melt or solution, contains processor for measuring complex permittivity as a function of electric field frequencies

Research paper thumbnail of Process for producing biopolymer nanoparticles

Research paper thumbnail of Coated waveguide for optical detection

Research paper thumbnail of Multi-level single mode 2D polymer waveguide optical interconnects using nano-imprint lithography

Optics express, 2015

Single and multi-layer passive optical interconnects using single mode polymer waveguides are dem... more Single and multi-layer passive optical interconnects using single mode polymer waveguides are demonstrated using UV nano-imprint lithography. The fabrication tolerances associated with imprint lithography are investigated and we show a way to experimentally quantify a small variation in index contrast between core and cladding of fabricated devices. 1x2 splitting devices based on directional couplers and multimode interference interferometers are demonstrated to have less than 0.45 dB insertion loss with 0.02 ± 0.01 dB power imbalance between the outputs. We demonstrate an 'optical via' with an insertion loss less than 0.45 dB to transfer light from one optical signal plane to another. A 1x4 two-dimensional optical port is experimentally demonstrated to spatially split the input power with an insertion loss of 1.2 dB.

Research paper thumbnail of Optical coupling structure made by imprinting between single-mode polymer waveguide and embedded VCSEL

Optical Interconnects XV, 2015

Polymer-based integrated optics is attractive for inter-chip optical interconnection applications... more Polymer-based integrated optics is attractive for inter-chip optical interconnection applications, for instance, for coupling photonic devices to fibers in high density packaging. In such a hybrid integration scheme, a key challenge is to achieve efficient optical coupling between the photonic chips and waveguides. With the single-mode polymer waveguides, the alignment tolerances become especially critical as compared to the typical accuracies of the patterning processes. We study novel techniques for such coupling requirements. In this paper, we present a waveguide-embedded micro-mirror structure, which can be aligned with high precision, even active alignment method is possible. The structure enables 90 degree bend coupling between a single-mode waveguide and a vertical-emitting/detecting chip, such as, a VCSEL or photodiode, which is embedded under the waveguide layer. Both the mirror structure and low-loss polymer waveguides are fabricated in a process based mainly on the direct-pattern UV nanoimprinting technology and on the use of UVcurable polymeric materials. Fabrication results of the coupling structure with waveguides are presented, and the critical alignment tolerances and manufacturability issues are discussed. Proc. of SPIE Vol. 9368 93680H-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 04/29/2015 Terms of Use: http://spiedl.org/terms

Research paper thumbnail of Average particle size in polymer blends obtained by dielectric spectroscopy

10th International Symposium on Electrets (ISE 10). Proceedings (Cat. No.99 CH36256), 1999

Previously we focussed on the dielectric properties of laminates and blends consisting of a weakl... more Previously we focussed on the dielectric properties of laminates and blends consisting of a weakly conducting and an insulating phase. Dielectric spectroscopy was used as a tool to obtain information about the dimensions of the conducting phase. With decreasing thickness of the conducting layer in the laminates, the permittivities measured were found to deviate more and more from those predicted

Research paper thumbnail of Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material

Optical Sensing and Detection III, 2014

ABSTRACT This paper describes experimental measurement results for photonic crystal sensor device... more ABSTRACT This paper describes experimental measurement results for photonic crystal sensor devices which have been functionalized for gas sensing applications. The sensor consists of a two dimensional photonic crystal etched into a slab waveguide having a refractive index of 1.7-1.9. Test devices were fabricated from SiON material on silicon / silicon dioxide platform, and also in polymer materials on silicon platform. The inorganic photonic crystals were made using direct write electron-beam lithography and reactive ion etching. The polymeric devices were made by nano-imprint lithography using the SiON structure as the imprint master. The high refractive index polymer was composed of a TiO2 - UV resin nanocomposite having a nanoparticle fraction between 50 and 60 wt%. This resulted in a tunable refractive index between 1.7 and 1.85. Devices were functionalized for gas sensing applications by coating the surface with a chemical receptor. This responsive layer reacts with the target gas and changes its refractive index. This change causes the angle of out-coupling to change slightly. In this paper we report successful detection of formaldehyde in air at sub ppm levels, and discuss details of chemical functionalization of the PC sensor.

Research paper thumbnail of Toward large-area roll-to-roll printed nanophotonic sensors

Optical Sensing and Detection III, 2014

ABSTRACT Polymers have become an important material group in fabricating discrete photonic compon... more ABSTRACT Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular imprint (MIP) functionalization methods were applied in the sensor demonstrators. In this paper, the process flow in fabricating large-area nanophotonic structures by the use of sheet-level and roll-to-roll UV- nanoimprinting is reported.

Research paper thumbnail of Coating based fiber Bragg grating humidity sensor array

OFS2012 22nd International Conference on Optical Fiber Sensors, 2012

Research paper thumbnail of Polymer-based optical interconnects using nanoimprint lithography

Optoelectronic Interconnects XIII, 2013

ABSTRACT The increasing request for higher data speeds in the information and communication techn... more ABSTRACT The increasing request for higher data speeds in the information and communication technology leads to continuously increasing performance of microprocessors. This has led to the introduction of optical data transmission as a replacement of electronic data transmission in most transmission applications longer than 10 meters. However, a need remains for optical data transmission for shorter distances inside the computer. This paper gives an overview of the Joint European project FIREFLY, in which new polymer based single mode waveguides are developed for integration with VCSELs, splitters and fibers that will be manufactured using multi-layer nanoimprint lithography (NIL). Innovative polymers, new applications of nano-technology, new methods for optical coupling between components, and the integration of all these new components are the technical ingredients of this ambitious project.

Research paper thumbnail of Solid-state potentiometric biosensors for pH quantification in biological samples

2011 IEEE SENSORS Proceedings, 2011

This paper reports on manufacturing and characterization of an all-solid-state potentiometric sen... more This paper reports on manufacturing and characterization of an all-solid-state potentiometric sensor aimed at monitoring pH in dialysate or blood plasma for patients who undergo dialysis. The sensing polymer-based membrane, coated on top of the Au working electrodes, contains a polymer matrix - poly(vinyl chloride), octadecyl isonicotinate as sensor molecule, plasticizer bis(2-ethyl hexyl) sebacate, and potassium-tetrakis(4-chlorophenyl) borate. The sensor was first calibrated over a wider pH interval, i.e. 5.0 – 9.0, and then for a pH interval which overlaps with the physiological pH, i.e. 7.0 – 8.0, followed by tests in human blood plasma. The response of the sensor is linear over the studied pH range, with a lifetime of two weeks and an accuracy of ∼ 0.08 pH. The response of the sensor is influenced by the storage conditions, and tests with sensors stored dry prior to potential measurements in buffers show that the sensor needs a few hours to reach an equilibrium, as opposed to seconds for the sensors stored in pH buffers prior to data collection. Monitoring the potential for 18 h continuously shows that the sensor does not drift. Toxicity and leaching of components from the sensor membrane into the liquid environment around it were studied, and determined which components were selected to further develop the pH sensor.