scholarly journals Optical Sensing of Humidity Using Polymer Top-Covered Bragg Stacks and Polymer/Metal Thin Film Structures

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 875 ◽  
Author(s):  
Katerina Lazarova ◽  
Darinka Christova ◽  
Rosen Georgiev ◽  
Biliana Georgieva ◽  
Tsvetanka Babeva
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Relative Humidity ◽  
Color Change ◽  
Metal Thin Film ◽  
Polymer Metal ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Selection Of ◽  
Bragg Stacks

Thin films with nanometer thicknesses in the range 100–400 nm are prepared from double hydrophilic copolymers of complex branched structures containing poly(N,N-dimethyl acrylamide) and poly(ethylene oxide) blocks and are used as humidity sensitive media. Instead of using glass or opaque wafer for substrates, polymer thin films are deposited on Bragg stacks and thin (30 nm) sputtered Au–Pd films thus bringing color for the colorless polymer/glass system and enabling transmittance measurements for humidity sensing. All samples are characterized by transmittance measurements at different humidity levels in the range from 5% to 90% relative humidity. Additionally, the humidity induced color change is studied by calculating the color coordinates at different relative humidity using measured spectra of transmittance or reflectance. A special attention is paid to the selection of wavelength(s) of measurements and discriminating between different humidity levels when sensing is performed by measuring transmittance at fixed wavelengths. The influence of initial film thickness, sensor architecture, and measuring configuration on sensitivity is studied. The potential and advantages of using top covered Bragg stacks and polymer/metal thin film structures as humidity sensors with simple optical read-outs are demonstrated and discussed.

scholarly journals Effect of environmental humidity on the ionic transport of poly(ethylene oxide) thin films, investigated by local dielectric spectroscopy

Soft Matter ◽  
2020 ◽  
Vol 16 (13) ◽  
pp. 3203-3208 ◽  
Author(s):  
Paul Markus ◽  
Daniel E. Martínez-Tong ◽  
Georg Papastavrou ◽  
Angel Alegria
Keyword(s):  
Thin Films ◽  
Relative Humidity ◽  
Ethylene Oxide ◽  
Dielectric Spectroscopy ◽  
Ionic Transport ◽  
Oxide Thin Films ◽  
Environmental Humidity ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

The laterally-resolved conductivity of PEO thin films increases with relative humidity, as determined by local dielectric spectroscopy: an AFM-based electrical technique.

scholarly journals Polymer Top-Covered Bragg Reflectors as Optical Humidity Sensors

Proceedings ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Katerina Lazarova ◽  
Rosen Georgiev ◽  
Darinka Christova ◽  
Tsvetanka Babeva
Keyword(s):  
Thin Films ◽  
Relative Humidity ◽  
Theoretical Modelling ◽  
Bragg Reflectors ◽  
Optical Contrast ◽  
Humidity Sensors ◽  
Operating Wavelength ◽  
Poly Ethylene Oxide ◽  
Branched Structures ◽  
Poly Ethylene

Thin films from double hydrophilic copolymer of complex branched structures containing poly(N,N-dimethyl acrylamide) and poly(ethylene oxide) blocks were used as humidity sensitive media, and two types of Bragg reflectors with different optical contrast and operating wavelengths were implemented as transducers of humidity changes. The required film thickness was pre-optimized through theoretical modelling in order to achieve the highest sensitivity. Single films and Bragg reflectors were characterized by transmittance measurements at different humidity levels in the range from 5% to 95% relative humidity. The influence of the number of the layers in the stack, the operating wavelength and optical contrast on sensitivity was studied. The potential and advantages of using top-covered Bragg reflectors as humidity sensors with simple optical read-out are demonstrated and discussed.

Symmetric Poly(ethylene oxide-b-styrene-b-isoprene) Triblock Copolymers: Synthesis, Characterization, and Self-Assembly in Bulk and Thin Film

2014 ◽  
Vol 47 (18) ◽  
pp. 6373-6381 ◽  
Author(s):  
Yali Qiao ◽  
Rachel Ferebee ◽  
Bongjoon Lee ◽  
Indranil Mitra ◽  
Nathaniel A. Lynd ◽  
...  
Keyword(s):  
Thin Film ◽  
Ethylene Oxide ◽  
Self Assembly ◽  
Triblock Copolymers ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

scholarly journals Effect of Environmental Humidity on the Ionic Transport of Poly(ethylene Oxide) Thin Films by Local Dielectric Spectroscopy

2019 ◽  
Author(s):  
Paul Markus ◽  
Daniel E Martínez-Tong ◽  
Georg Papastavrou ◽  
Angel Alegria
Keyword(s):  
Thin Films ◽  
Ethylene Oxide ◽  
Amorphous Phase ◽  
Dielectric Spectroscopy ◽  
Ionic Transport ◽  
Oxide Thin Films ◽  
Environmental Humidity ◽  
Dielectric Contrast ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

<div><div><div><p>The effect of humidity on the ionic transport in the amorphous phase of poly(ethylene oxide) thin films has been studied by via local dielectric spectroscopy. We explored a controlled humidity range between 15 %RH and 50 %RH. AFM-based local dielectric imaging allowed to obtain simultaneously the thin films topography and the corresponding dielectric contrast maps. No humidity effect on the film topography was observed whereas large variation of the dielectric signal could be detected. In addition, we observed a clear dielectric contrast in different locations on the thin film surface. At selected regions with high contrast in the dielectric maps, we performed nanoDielectric Spectroscopy (nDS) measurements covering the frequency range from 10 Hz to 100 kHz. By modeling these spectroscopy results, we quantified the conductivity of the amorphous phase of the semicrystalline poly(ethylene oxide) films. The crystalline fraction of the PEO thin films was extracted and found to be about 36%, independently of humidity. However, the average conductivity increased drastically from 2×10-10 to 5×10-9 S/cm, by changing environmental humidity in the explore %RH range.</p></div></div></div>

Solvent-tuning of ordered mesoporous silicas prepared through evaporation-induced self-assembly templated by poly(ethylene oxide-b-ε-caprolactone)

RSC Advances ◽  
2014 ◽  
Vol 4 (105) ◽  
pp. 61012-61021 ◽  
Author(s):  
Wei-Cheng Chu ◽  
Chen-Xin Lin ◽  
Shiao-Wei Kuo
Keyword(s):  
Ethylene Oxide ◽  
Self Assembly ◽  
Mesoporous Silicas ◽  
Size Distributions ◽  
Ordered Mesoporous ◽  
Pore Size Distributions ◽  
Evaporation Induced Self Assembly ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Selection Of

Highly ordered mesoporous silicas having narrow pore size distributions and various morphologies merely through selection of an appropriate solvent.

Systematic Control of Self-Seeding Crystallization Patterns of Poly(ethylene oxide) in Thin Films

2018 ◽  
Vol 51 (5) ◽  
pp. 1626-1635 ◽  
Author(s):  
Binghua Wang ◽  
Shaohua Tang ◽  
Yan Wang ◽  
Changyu Shen ◽  
Renate Reiter ◽  
...  
Keyword(s):  
Thin Films ◽  
Ethylene Oxide ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Systematic Control

Modified Decohesion Test (MDT) for Interfacial Fracture Toughness Measurement in Microelectronic/MEMS Applications

2002 ◽  
Author(s):  
Mitul B. Modi ◽  
Suresh K. Sitaraman
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Fracture Toughness ◽  
Energy Release ◽  
Physical Vapor Deposition ◽  
Interfacial Fracture ◽  
Interfacial Fracture Toughness ◽  
Testing Methods ◽  
Structural Variations ◽  
Metal Thin Film

Delamination of intrinsically or residually stressed thin films is commonly encountered in microelectronics and MEMS systems. Thin films typically accrue stresses through micro structural variations caused by physical vapor deposition, thermally induced stresses imposed due to thermal mismatch, and/or extrinsically introduced forces. These stresses can reach upwards of 1 GPa and can easily exceed the strength of the metal thin film interface. Knowledge of the interfacial fracture toughness (Γ) is necessary to predict if delamination will occur. However, measuring Γ is a challenge for thin film interfaces. Typical testing methods such as bimaterial cantilever, microscratch, peel, bulge, or edge lift-off are limited to organic films, cause complex stress fields, can only measure a single mode mix, or cannot achieve the large energy release rates typical of metal thin film interfaces. A new approach based on the decohesion test, called the modified decohesion test (MDT), eliminates these shortcomings of current testing methods. In this approach, a highly stressed super layer is used to drive delamination and “tune-in” the mode mix at the crack tip. Since the deformations remain elastic, a mechanics-based solution can be used to correlate test parameters to the energy release rate. Common IC fabrication techniques are used to prepare the sample and execute the test, thereby making the test compatible with current microelectronic or MEMS facilities. Varying the crack surface area rather than the energy in the super layer allows the ability to bound Γ using a single test wafer providing a 90% savings in resources and 95% savings in time. Other modifications allow application of the method to highly chemically reactive metals and decrease the sample preparation time. Design, preparation, and execution of the MDT are presented. Results of finite element models are used to validate the approach. Results are shown for a Ti/Al2O3 interface.

scholarly journals Effect of Thickness on Phase Transition of Poly(ethylene oxide) Thin Film

Netsu Bussei ◽  
2014 ◽  
Vol 26 (4) ◽  
pp. 203-208 ◽  
Author(s):  
Masayuki Iwasa ◽  
Kana Emoto ◽  
Ryuta Wakairo ◽  
Shinya Nishimura ◽  
Hirohisa Yoshida
Keyword(s):  
Thin Film ◽  
Phase Transition ◽  
Ethylene Oxide ◽  
Oxide Thin Film ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene
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