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The recent development in smart material-based actuators are composite structures of thin film integrated SMA/PI bimorph in the view of actuator cum sensing in electromechanical systems for medical, robotics, and aerospace application. The purpose of the present work on integrated SMA/PI bimorph is to reveal their ability to perform as actuators and sensors and study on control characteristics for soft robotic, positioning, and valve applications. Vide this research paper, the SMA bimorph actuator [thin film SMA (CuAlNi)/polyimide (Kapton) bimorph] is used as actuator cum sensor for position control. Proposed a Proportional Derivative combined Variable Structure Controller (PD-VSC) to control the displacement by Joule heating actuation in two ways, which are sensor-based control and self-sensing control. From the control characteristics in from of tracking and disturbance rejection, it is concluded that the integrated CuAlNi/Kapton bimorph can be successfully implemented for soft robotic, positioning, and valve applications. [ABSTRACT FROM AUTHOR]

To solve the non-uniformity of stress in space membrane structure and the lack of shear compliant border configuration design method, shear compliant borders are designed, optimized, and verified in terms of configuration. Firstly, an orthotropic model of the borders is built by combining Hill and Christensen-Lo composite material models. Secondly, a finite element form-finding method is put forward by establishing rectangular and cylindrical coordinates in different areas. The configuration of borders is obtained and the influence of the borders on the edge of the membrane is 0.23%, which means that the borders are compatible with the existing tensegrity systems, especially the tensioning components and the cable sleeves. Thirdly, simulation verifies that borders can cut the spread of shear stress and improve the stress uniformity in membrane structure. The maximum stress in the membrane effective area is decreased by 35.6% and the stress uniformity is improved by 30.5%. Finally, a membrane extension experiment is committed to compare the flatness of membrane surface under shear stress with and without shear compliant borders. The borders decrease the increment speed of flatness by 58.1%, which verifies the amelioration of stress uniformity. The shear compliant border configuration design method provides a reference for space membrane structure stress-uniform design. [ABSTRACT FROM AUTHOR]

Undoped and In‐doped ZnSb thin films are deposited on rigid glass and flexible polyimide (Kapton) by physical vapor deposition. Detailed structural and chemical characterization is performed along with measurement of electrical and optical properties. These properties are very similar for films on glass and Kapton. Flexible ZnSb films show remarkable stability of electrical and optical properties, which are unchanged after 104 cycles of linear bending with surface strain 0.18%. Only severe flexing after this treatment (torsional bending with surface strain 1.7%) causes progressive degradation of conductivity over tens to hundreds of cycles. The ZnSb optical direct gap is determined to be 0.89 ± 0.05 eV. The optical direct gap of β Zn4Sb3 was 1.07 ± 0.05 eV. Other absorption features in the films, including smaller indirect gaps, are discussed. [ABSTRACT FROM AUTHOR]

To improve the atomic oxygen (AO) erosion resistance of Kapton for application as an aerospace material in low earth orbit (LEO), a graphene-modified polysiloxane-60 vol.% SiO2 (G-PSS) composite coating was prepared and tested for AO exposure at a total flux of 1.86 × 1020 atoms/cm2. The prepared coating with a thickness of 5 μm was smooth, with good adhesion and no macroscopic defects. Its AO erosion yield was 9.77 × 10−27–1.25 × 10−26 cm3/atom, which was about three orders and one order of magnitude lower than that of Kapton and polysiloxane-60vol.%SiO2 (PSS) hybrid coating, respectively. The beneficial effect of graphene was attributed to the effective inhibition of gas permeation by the single-layer graphene due to its unique structure and the more stable epoxy groups produced during the reaction of graphene with AO. [ABSTRACT FROM AUTHOR]

A novel strip line fed, circularly polarized (CP), annular slotted dual band antenna using hybrid electromagnetic band gap (EBG) structure for Global Positioning System (GPS) has been herein designed, analyzed, and investigated for wearable applications. Adjusting the radii of the annular slots on the radiating patch excellent circular polarized (CP) radiation and impedance matching is achieved. The design demonstrates Kapton based flexible, robust, and low-profile solution with permittivity of 3.4 to meet the requirements of wearable applications. Due to the high losses of the animal body, the electromagnetic band gap (EBG) structure is used to reduce back radiation and the effect of frequency detuning. The proposed antenna structure also enhances the front-to-back ratio (FBR) by 10 dB. This antenna with dimensions 0.56λ0 × 0.4913λ0 × 0.002λ0 analyzed using a flexible Kapton substrate. Optimized hybrid EBG structure provides an excellent Specific Absorption Rate (SAR) along with all other antenna parameters, within acceptable for GPS-based wearable applications at 1.13 GHz and 1.157 GHz frequency band. Therefore the proposed antenna is a suitable candidate for GPS-based tracking and wireless body area network (WBAN) applications. The proposed antenna was also tested upon fabrication and the measured results agree with simulated results. [ABSTRACT FROM AUTHOR]

Abstract Undoped and In‐doped ZnSb thin films are deposited on rigid glass and flexible polyimide (Kapton) by physical vapor deposition. Detailed structural and chemical characterization is performed along with measurement of electrical and optical properties. These properties are very similar for films on glass and Kapton. Flexible ZnSb films show remarkable stability of electrical and optical properties, which are unchanged after 104 cycles of linear bending with surface strain 0.18%. Only severe flexing after this treatment (torsional bending with surface strain 1.7%) causes progressive degradation of conductivity over tens to hundreds of cycles. The ZnSb optical direct gap is determined to be 0.89 ± 0.05 eV. The optical direct gap of β Zn4Sb3 was 1.07 ± 0.05 eV. Other absorption features in the films, including smaller indirect gaps, are discussed.

The growing population of space debris in the near-Earth environment means there is an increased need for space-based detectors, capable of measuring and distinguishing natural space dust and anthropogenic orbital debris populations, to monitor and quantify the relative threat they pose. This has led to much research into the development of new detectors, including those based on time of flight (TOF) designs which can give impact speed and direction. Kapton's favourable properties (e.g. its low mass and ability to be manufactured as thin films) and tried and tested space applications, suggest it may be suitable for use in TOF detectors where impactor speed is measured by passage through several films with known separation. To test the measurement accuracy of such a detector, a prototype Kapton based TOF space dust and debris detector was constructed, and impacted at 2 and 4 km s−1. For a Kapton film thickness of 12.5 μ m and projectiles of 1 mm in size, within experimental uncertainties of ∼1%, there was no difference between incident projectile speed (as measured independently) and that measured by the TOF detector. This, confirms that Kapton based TOF detectors are capable of measuring particle speed to a high degree of accuracy, making them suitable for measuring the near-Earth particle environment. [ABSTRACT FROM AUTHOR]

To solve the non-uniformity of stress in space membrane structure and the lack of shear compliant border configuration design method, shear compliant borders are designed, optimized, and verified in terms of configuration. Firstly, an orthotropic model of the borders is built by combining Hill and Christensen-Lo composite material models. Secondly, a finite element form-finding method is put forward by establishing rectangular and cylindrical coordinates in different areas. The configuration of borders is obtained and the influence of the borders on the edge of the membrane is 0.23%, which means that the borders are compatible with the existing tensegrity systems, especially the tensioning components and the cable sleeves. Thirdly, simulation verifies that borders can cut the spread of shear stress and improve the stress uniformity in membrane structure. The maximum stress in the membrane effective area is decreased by 35.6% and the stress uniformity is improved by 30.5%. Finally, a membrane extension experiment is committed to compare the flatness of membrane surface under shear stress with and without shear compliant borders. The borders decrease the increment speed of flatness by 58.1%, which verifies the amelioration of stress uniformity. The shear compliant border configuration design method provides a reference for space membrane structure stress-uniform design.

Although laser ablation of polymers is well investigated the achievable surface quality of this process is limited due to laser-induced structural and morphological defects, arising surface roughness and redeposition of debris. Because high quality machining with laser radiation is highly requested, laser-induced plasma etching (LIPE) of polyimide film is studied for the development of ultraprecise surface machining (UPSM) techniques for various applications. Thus, the key parameters such as laser power, etching time, plasma distance of the LIPE are studied experimentally to explore the impact to the etching rate and the surface morphology. LIPE rates as low as 1 pm per laser pulse were measured that fulfil UPSM requirements. The footprint of the LIPE is circular shaped and enable therefore the development of areal processing strategies for surface correction, aspherization and freeform processing. In addition, regular nanostructures that feature a highly regular hexagonal pattern with a period of 117 nm to 125 nm were found at particular conditions.

The presence of heavy metal ions in soil, air and water constitutes an important global environmental threat, as these ions accumulate throughout the food chain, contributing to the rise of chronic diseases, including, amongst others, cancer and kidney failure. To date, many efforts have been made for their detection, but there is still a need for the development of sensitive, low-cost, and portable devices able to conduct on-site detection of heavy metal ions. In this work, we combine microfluidic technology and electrochemical sensing in a plastic chip for the selective detection of heavy metal ions utilizing DNAzymes immobilized in between platinum nanoparticles (PtNPs), demonstrating a reliable portable solution for water pollution monitoring. For the realization of the microfluidic-based heavy metal ion detection device, a fast and easy-to-implement fabrication method based on the photolithography of dry photosensitive layers is proposed. As a proof of concept, we demonstrate the detection of Pb2+ ions using the prototype microfluidic device. [ABSTRACT FROM AUTHOR]

The hydrolytic stability of polyimide films (PI) in a 0.9% sodium chloride solution in the temperature range of existing biological objects was studied. The kinetic parameters of hydrolysis of PI films were calculated. It was established that the hydrolysis rate constant of an adamantane-containing film was significantly lower than that of an industrial Kapton film. The dielectric constant after hydrolysis was determined. It was shown that the dielectric properties of the adamantane-containing polymer remained unchanged under the hydrolysis conditions. [ABSTRACT FROM AUTHOR]

A highly flexible coating deposited on organic substrates is one of the most suitable techniques for efficient atomic oxygen (AO) resistance in low Earth orbit (LEO). In this study, a highly homogeneous methyl silicone rubber coating as an AO-tolerant material was fabricated on a flexible Kapton film by a spraying process used in a photovoltaic solar array blanket. The produced silicone rubber coating has excellent AO resistance and exhibits a low shrinkage tendency after evaluating the effect of atomic oxygen on the erosion kinetics, surface morphology, and surface composition of this coating. The erosion yield of the silicone rubber-coated Kapton, which was less than 3.1% of that of the Kapton, was less than 0.92 × 10−25 cm3 atom−1 under an AO fluence of 4.04 × 1021 atoms cm−2 (equiv 10 years of AO exposure in the LEO with an altitude of 500 km). It suggests that the silicone rubber layer can effectively prevent AO from eroding Kapton. In addition, a SiO2 passivation layer was formed on the surface of the silicone rubber coating during AO irradiation, which demonstrated a "self-reinforcing" protection mechanism. This work also provides a facile method for designing and preparing large-scale flexible protective coatings with excellent AO resistance. [ABSTRACT FROM AUTHOR]

Atomic oxygen in the low Earth orbit (LEO) environment is highly oxidizing. Due to the high flight speed of spacecraft, the relative kinetic energy of high-flux atomic oxygen bombarding the spacecraft surface can reach up to about 5 eV. Therefore, atomic oxygen is one of the most dangerous space environment factors in LEO, which seriously affects the safe operation and service life of spacecraft in orbit. In order to meet the requirements for the high reliability and long lifetime of spacecraft, effective protection measures must be taken on their sensitive surfaces. Siloxane is a coating with an organic–inorganic hybrid structure. Compared with SiO2 and other inorganic atomic oxygen protective coatings, it has better flexibility and is better at anti-atomic oxygen performance. In this paper, the plasma polymerization deposition technique was used to prepare large-area siloxane coatings on different substrates with different thicknesses for improving atomic oxygen resistance by optimizing the process parameters. The thickness of the coating was measured by different methods, and the results showed that the thickness distribution was consistent. By observing the surface morphology of the coating, it was uniform and compact without obvious defects, so the uniformity of large-area coating was also ideal. The adhesion and heat/humidity resistance of siloxane coatings were examined by pull-off testing and damp-heat testing, respectively. The results showed that the siloxane coatings with a thickness of about 400 nm exhibited better physical properties. At the same time, the ground simulation testing of atomic oxygen confirmed that siloxane coatings with a thickness of 418 nm presented the best performance of atomic oxygen resistance. The atomic oxygen erosion yield of siloxane coatings with a thickness of 418 nm was as low as 5.39 × 10−27 cm3/atoms, which was three orders of magnitude lower than that of the uncoated Kapton substrate and presented a good anti-atomic oxygen performance. Meanwhile, it has also successfully passed the damp-heat test. The coating thickness is only several hundred nanometers and does not increase the weight of the spacecraft, which makes it a relatively ideal LEO atomic oxygen protection material. Furthermore, a possible mechanism was proposed to explicate the physicochemical process of atomic oxygen attacking the coating materials. [ABSTRACT FROM AUTHOR]

Experimental study of current-voltage (I-V) characteristics and frequency dependences of impedance in copper-Kapton-copper structures in the temperature range 240 – 300 K were carried out. Concentration and mobility of charge carriers thermally excited from traps with exponential distribution by energy in Kapton bulk and metal-Kapton interface and injected from copper electrodes into Kapton were estimated from the fitting of experimental I-V curves within the frame of the model of the space charge limited current (SCLC). Concentration and the width of energy of localized states, arising from the disorder of the Kapton structure, are additionally estimated from the I-V characteristics.

Gadolia-doped Ceria-Barium Monoferrite (GDC-BaFe 2 O 4) thin films have been deposited on Kapton sheets using the DC sputtering method as electromagnetic (EM) wave-absorbing materials. The present study has examined the structural, magnetic, and microwave absorption properties of GDC-BaFe 2 O 4. The primary approaches used in this investigation included changing the surface form and applying EM wave-absorbing materials as surface coatings. X-ray diffraction research showed that the GDC-BaFe 2 O 4 thin films have an orthorhombic crystal structure. The bonding investigation revealed the existence of Fe-O, Ce-O, and Ba-O-Ba functional groups at 426.87, 517.42 and 1014.84 cm−1, respectively. Vibrating-sample magnetometry confirmed that saturation magnetization decreased with increasing sputtering time and revealed the ferromagnetic behavior of the GDC-BaFe 2 O 4 thin film. Ce, Gd, Ba, Fe, and O were evenly and similarly distributed over the Kapton surface of the GDC-BaFe 2 O 4 thin films, according to energy-dispersive X-ray spectroscopy and scanning electron microscopy. Based on the atomic force microscopy test, the root-mean-square roughness (R q) increased during the ion implantation procedure. With a 7.5-minute sputtering period, the microwave absorption ability reached a maximum reflection loss value of −39.6 dB (99.98 %) at 10 GHz. As a result of these findings, GDC-BaFe 2 O 4 appears to be a promising candidate for EM wave absorption. • DC sputtering was successfully used to generate Gadolia-doped Ceria-Barium Monoferrite thin films on Kapton substrates. • Ion implantation is used to modify the surface geometry of absorbent materials. • The GDC-BaFe 2 O 4 thin film has the ferromagnetic behavior. • The microwave absorption ability reaches a maximum reflection loss value of −39.66 dB (99.98 %) in the range of 10 GHz. • The GDC-BaFe 2 O 4 material was promising prospect for application as a microwave absorbing waves. [ABSTRACT FROM AUTHOR]

Advanced wireless communication technology claims miniaturized, reconfigurable, highly efficient, and flexible meta-devices for various applications, including conformal implementation, flexible antennas, wearable sensors, etc. Therefore, bearing these challenges in mind, a dual-band flexible metamaterial absorber (MMA) with frequency-reconfigurable characteristics is developed in this research. The geometry of the proposed MMA comprises a square patch surrounded by a square ring, which is mounted over a copper-backed flexible dielectric substrate. The top surface of the MMA is made of silver nanoparticle ink and a middle polyethylene terephthalate (PET) substrate backed by a copper groundsheet. The proposed MMA shows an absorption rate of above 99% at 24 and 35 GHz. In addition, the absorption features are also studied for different oblique incident angles, and it is found that the proposed MMA remains stable for θ = 10–50°. The frequency tunability characteristics are achieved by stimulating the capacitance of the varactor diode, which connects the inner patch with the outer ring. To justify the robustness and conformability of the presented MMA, the absorption features are also studied by bending the MMA over different radii of an arbitrary cylinder. Moreover, a multiple-reflection interference model is developed to justify the simulated and calculated absorption of the proposed MMA. It is found that the simulated and calculated results are in close agreement with each other. This kind of MMA could be useful for dual-band sensing and filtering operations. [ABSTRACT FROM AUTHOR]

In order to study the bio-samples (aqueous solutions) using muon spin rotation and relaxation (mSR) method, the optimization of momentum of incident muon beam and selection of material for window of sample cell towards muon side are the initial steps for the mSR measurement. Rather than several experimental trials, we used to perform simulation study to optimize the momentum of muon beam and thickness of window of the sample cell. Monte Carlo simulation for optimization of momentum of monoenergetic surface muon beam in different material/thickness of window of the sample cell indicates that the Al or Kapton window of thickness less than 0.3 mm is suitable to maximize the intensity of the stopped muons (momentum between 25.8 MeV/c to 29.8 MeV/c) within 1 mm of water (bio-samples). This simulation will help to design the sample cell for the study of application of muon in life science. BIBECHANA 19(2022)160-164

The presence of heavy metal ions in soil, air and water constitutes an important global environmental threat, as these ions accumulate throughout the food chain, contributing to the rise of chronic diseases, including, amongst others, cancer and kidney failure. To date, many efforts have been made for their detection, but there is still a need for the development of sensitive, low-cost, and portable devices able to conduct on-site detection of heavy metal ions. In this work, we combine microfluidic technology and electrochemical sensing in a plastic chip for the selective detection of heavy metal ions utilizing DNAzymes immobilized in between platinum nanoparticles (PtNPs), demonstrating a reliable portable solution for water pollution monitoring. For the realization of the microfluidic-based heavy metal ion detection device, a fast and easy-to-implement fabrication method based on the photolithography of dry photosensitive layers is proposed. As a proof of concept, we demonstrate the detection of Pb2+ ions using the prototype microfluidic device.

In this article, we report on the electrical performance of AlGaN/GaN high-electron mobility transistors (HEMTs) fabricated using gold (Au)-free process, after being transferred onto flexible Kapton tape. The transfer process followed in this work can be easily scaled-up to wafer level and involves a relatively simple process of epoxy bonding of the thin device layer onto the Kapton substrate. Electrical characteristics of the flexible HEMT indicate 5%–10% higher ON-current when bent with a radius of curvature of 2.1 cm (at low drain bias voltages), while the OFF-state performance remains unaffected. Initially, 2-DEG properties such as field-effect mobility and carrier concentration have been extracted. While FATFET measurements indicate negligible change in field-effect mobility, ${C}$ – ${V}$ measurements indicate $\sim 10$ % reduction in 2-DEG concentration after transfer. The comparison of the electrical characteristics of Au-free HEMTs indicates $\sim 50$ % reduction in the ON-current of the transferred devices. This is attributed to heating of the transistor channel caused due to low thermal conductivity of the polymer Kapton tape. Electrical characteristics of the flexible HEMT carried out under drain pulsing further support the above observation. This work is among one of the few reports on Au-free AlGaN/GaN HEMT operation on flexible Kapton tape. [ABSTRACT FROM AUTHOR]

Elastic peak electron spectroscopy (EPES) was employed to measure the inelastic mean free path (IMFP) for energies between 500 and 1600 eV for five insulating organic compounds: Kapton, polyethylene (PE), poly(methyl methacrylate) (PMMA), polystyrene (PS) and polytetrafluoroethylene (PTFE). A Ni and a Si sample were used as reference materials to avoid measurement of the elastic reflection coefficient in absolute units. Correction of experimental elastic peak intensities for surface excitations was performed which turned out to be essential. The results are compared with recent evaluations of optical constants to yield the IMFP in the literature giving satisfactory agreement, with deviations generally below 20%. Investigation of the kinematics in an electron reflection experiment shows that the dispersion coefficient used in REELS data analysis cannot be identified with the true plasmon dispersion. [ABSTRACT FROM AUTHOR]

Toxic gases are responsible for the loss of many human lives around the world, which is increasing every year. Toxicity can have various biological aspects on the human body. The exposure to its gases leads to harmful consequences for the organism, which leads to metabolic reactions and even death. For this purpose, the initial step is to detect these gases with miniature flexible structures and solid progressed estimation methods using a simulation software tool. The studied sensor is based on the frequency characterization of an RF Planar Resonant Structure, in which the active element is a patch of radiating graphene printed on a polyimide film (Kapton). The objective of this work is to use our Graphene-Kapton sensor for non-invasive testing applications. In our case, the device is tested to detect and recognize several dangerous and toxic gases such as Fluorine azide (F2N), Hydrogen Iodide (HI), Nitrogen (N2), Methane (CH4), and Carbon monoxide (CO). The simulation results indicate that the Graphene-Kapton flexible sensor exhibits an important sensing performance. The sensor is able to detect all the tested gases with a good sensitivity depending on each gas. As well as, the sensor shows a high sensitivity (0.1± 0.01)* 106 [ppm]-1 (0.1 [ppt]-1) of methane (CH4) gas with detection limit of (9±0.1) *10-6 ppm (9 ppt). [ABSTRACT FROM AUTHOR]

Reflection electron energy loss spectra (REELS) were measured for five insulating organic compounds: Kapton, polyethylene (PE), poly(methyl methacrylate) (PMMA), polystyrene (PS) and polytetrafluoroethylene (PTFE), as well as for Ni and Si, in the energy range between 200 and 1600 eV. The average number of surface excitations for a single surface crossing were determined from the experimental data and were found to be considerably smaller than for earlier studied materials, which mainly consisted of elemental metals [Surf. Sci. 486(2001)L461]. The surface excitation parameter, a material parameter used to quantify the relative intensity of surface losses in (photo)electron spectroscopy, was extracted from the data and compared with values found in the literature. The results indicate that surface excitations only have a minor influence on quantification of XPS spectra of polymers. On the other hand, a correction for surface excitations turns out to be essential for measurements of the electron inelastic mean free path of polymers when a metal is used as reference material. [ABSTRACT FROM AUTHOR]

The process requirements for ultra-precise machining of surfaces for optical applications is still challenging for laser ablation-based methods. The LIPE (laser-induced plasma etching) method combines the two complementary techniques of laser and plasma processing. Technologically important materials like SiO2, Ge, Si as well fiber-reinforced composites (SiC-SiC) have been successfully processed with LIPE, in particular Polyimide (Kapton@ HN (125 µm)) and Polyethylenterephthalat. In the present paper, LIPE etching of polymer surface is demonstrated. The influence of the main process parameters on the etching rate as well as on the obtained surface characteristics will be shown and discussed in detail. [ABSTRACT FROM AUTHOR]

Remote propulsion of miniature mechanical devices possesses a great challenge to the scientific community. Herein, a lightweight two‐way shape memory polymer (2WSMP)‐based motor is presented, which operates a demo vehicle via a novel infrared‐irradiated 2WSMP actuator. Most of the polymers that possess 2WSMP properties suffer from inadequate mechanical properties and low durability in harsh environments. Herein, the 2WSMP bilayer actuator, based on Kapton and polyPOSS (PP), possesses superior 2WSMP and mechanical properties, high lifting abilities, and durability in harsh environments. Kapton is well known for its outstanding physical properties. PP, a polyhedral oligomeric silsesquioxane (POSS)‐based epoxy‐like thermoset, possesses unique properties. Its advanced ability to maintain mechanical properties over a range of temperatures, while presenting a constant coefficient of thermal expansion, is essential for its 2WSMP actuation properties. The effects of the Kapton and PP layers' thickness on the force and deflection, generated by the 2WSMP actuators during heating, are studied. A theoretical model is used to predict the actuator's deflection, based on the layers' thickness. These actuators present excellent thermal stability at temperatures as high as 150 °C, while maintaining outstanding motion repeatability and extremely high lifting capacity of up to 6500 times of their own weight. [ABSTRACT FROM AUTHOR]

Remote propulsion of miniature mechanical devices possesses a great challenge to the scientific community. Herein, a lightweight two‐way shape memory polymer (2WSMP)‐based motor is presented, which operates a demo vehicle via a novel infrared‐irradiated 2WSMP actuator. Most of the polymers that possess 2WSMP properties suffer from inadequate mechanical properties and low durability in harsh environments. Herein, the 2WSMP bilayer actuator, based on Kapton and polyPOSS (PP), possesses superior 2WSMP and mechanical properties, high lifting abilities, and durability in harsh environments. Kapton is well known for its outstanding physical properties. PP, a polyhedral oligomeric silsesquioxane (POSS)‐based epoxy‐like thermoset, possesses unique properties. Its advanced ability to maintain mechanical properties over a range of temperatures, while presenting a constant coefficient of thermal expansion, is essential for its 2WSMP actuation properties. The effects of the Kapton and PP layers’ thickness on the force and deflection, generated by the 2WSMP actuators during heating, are studied. A theoretical model is used to predict the actuator's deflection, based on the layers’ thickness. These actuators present excellent thermal stability at temperatures as high as 150 °C, while maintaining outstanding motion repeatability and extremely high lifting capacity of up to 6500 times of their own weight.

The increasing usage of perovskite solar cells is being driven by their high efficiency and cost-effective manufacture. Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN) are flexible, transparent, and cost-effective. However, issues have been raised about their long-term stability, especially to the sensitivity of perovskite materials to environmental conditions like as moisture and heat, as well as the challenge of oxygen and moisture transmission across these substrates. Researchers are investigating Polyimide (PI), particularly colorless PI, for enhanced stability, but the techniques are costly. Kapton, a popular colored PI, provides excellent thermal and electrical insulation, but its reduced transparency provides optical issues. In this study, finite-difference-time-domain (FDTD) modeling and experimental analysis were utilized to investigate the optical properties and efficiency of perovskite solar cells on Kapton, PET, and glass substrates. According to the modeling, using Kapton instead of traditional substrates leads to a decrease of 16.6 % in the solar cells short circuit current (J SC). In laboratory experiments, by adding lithium (Li) as the dopant in the electron transport layer (ETL), the sheet resistance of the ETL was reduced from 214 to 2.4 kΩ/□. According to modeling, this enhancement resulted in a 3 % increase in the power conversion efficiency (PCE) of the solar cell, increasing to 17.4 % compared to 16.8 % on a PET substrate. Furthermore, using a Kapton substrate improves critical performance parameters like open circuit voltage (V OC) and fill factor (FF). • FDTD simulation for flexible perovskite solar cell structure. • Kapton substrate reduces absorption in perovskite layer compared to PET. • Deposited TiO 2 layer on Kapton has fine particle distribution and high coverage. • Li-doped TiO 2 enhances electron transport, V OC , and FF in solar cells. • Modified flexible solar cell on Kapton displayed 17.4 % efficiency. [ABSTRACT FROM AUTHOR]

Experimental study of current-voltage (I-V) characteristics and frequency dependences of impedance in copper-Kaptoncopper structures in the temperature range 240 - 300 K were carried out. Concentration and mobility of charge carriers thermally excited from traps with exponential distribution by energy in Kapton bulk and metal-Kapton interface and injected from copper electrodes into Kapton were estimated from the fitting of experimental I-V curves within the frame of the model of the space charge limited current (SCLC). Concentration and the width of energy of localized states, arising from the disorder of the Kapton structure, are additionally estimated from the I-V characteristics. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge (DBD) plasma actuators are simple electrohydrodynamic devices, which are able to provide effective aerodynamic control. One of the main components of these devices is the thin dielectric layer, which allows to separate and prevent the arc between the high‐voltage electrodes. Different materials can be used as dielectric layer to reduce the power consumption or boost the flow controlling effect of the actuators. In this context, this report presents a comparative study of two commercial polyimides, Kapton and Cirlex, used as dielectric layer of surface DBD plasma actuators. The electrical, dielectric, mechanical, electromechanical, and thermal properties were obtained to evaluate overall performance. It was verified that Cirlex (8.3 W) consumes less power than Kapton (21.3 W) to generate higher induced flow velocity of ≈3.4 m/s for an input voltage of 11 kVpp and 24 kHz. During one AC cycle at 11 kVpp the charge transferred for Cirlex (70 nC) is lower than for Kapton (100 nC), as well as the dielectric breakdown voltage to ignite the plasma discharge, 1.5 and 2.2 kVpp, respectively. The Cirlex DBD presents a higher voltage operation limit (at least 14 kVpp) and a more regular plasma discharge, which results in a more homogenous thermal profile and temperature distribution during its operation. The Cirlex actuator delivered higher mechanical power (6.2 mW) and achieved higher electromechanical efficiency (0.004%). The polyimide Cirlex proved to be a suitable alternative for Kapton to fabricate DBD plasma actuators for flow control with improved performance. [ABSTRACT FROM AUTHOR]

This paper presents a polarization-independent 11-bit chipless RFID tag based on frequency-selective surface which has been designed for encoding and relative humidity (RH) sensing applications. The 10 exterior U-shaped resonators are used for item encoding whereas Kapton has been incorporated with the interior resonator for RH sensing. This radio-frequency identification (RFID) tag operates in S- and C-frequency bands. The proposed design offers enhanced fractional bandwidth up to 88% with the density of 4.46 bits/cm2. Both single- and dual-layer tags have been investigated. The simulated results are in good agreement with measured results and a comparison with existing literature is presented to show the performance. Simple geometry, high code density, large frequency signature bandwidth, high magnitude bit, high radar cross-section, and angular stability for more than 75° are the unique outcomes of the proposed design. In addition, RH sensing has been achieved by integrating the Kapton on the same RFID tag. [ABSTRACT FROM AUTHOR]

The Triboelectric nanogenerators (TENGs) are Fabricated by contact between two surfaces of different materials and convert of electric loads between them. In such structures, the two contacting layers should be radically different in terms of their electric property so that one of the layers could induce positive electrical charge while the other induces a negative charge. The application of force on and friction between the two layers induce positive and negative charges. Through the electrodes in external load, the electrical charges flow as electric current. In the present study, TEGN structures fabricated of polyethylene terephthalate polymers (PET) act as electron acceptor while Polyamide (KAPTON) and polydimethylsiloxane (PDMS) act as electron donator. The resulting outputs are compared consequently. Considering the fact that the two materials are relatively identical in terms of electron donation as they are in contact with PET, the generators fabricated of KAPTON could generate 400% more power under identical conditions. Therefore, one may conclude that KAPTON could be more suitable for development of self-power system as they are more available and more environmentally compatible. [ABSTRACT FROM AUTHOR]

Contact electrification is a direct triboelectrification method for producing current through charge transfer when two different differentiated materials have brought into contact. For the first time, we developed a simple triboelectric nanogenerator (TENG) where the electronic charges were realized through contact separation mode between sand-polished Kapton (SPK) and Al surface. Here, we demonstrated the energetic interfacial contact between these surfaces and observed satisfactory output performance. The novel SPK-TENG produced 40 V and 2.8 µA, of open-circuit voltages (Voc) and short-circuit currents (Isc) at 4 Hz, respectively. Mainly, the SPK-TENG was dramatically increased up the performance of TENG, up to 40% of Voc and 42% of Isc, with respect to the Kapton film because the mobility of electrons is very high on the device surface compared to the other pristine Kapton film. The fabricated SPK-TENGs were good candidates for satisfying the need for alternative contact separation mode TENGs.

• Hypervelocity impact flash is reported on thin Kapton films at speeds up to 5 km s −1. • The flashes from two layers of film provide a time of flight and hence projectile speed. • The accuracy of the speed is good to 1%. The impact flash from hypervelocity impact on thin (12.5 µm) Kapton film was observed. The projectile sizes ranged from 0.1 to 1 mm, with speeds from 2 to 5 km s−1 and penetrated the Kapton intact, leaving holes the same size as the projectile (to within measurement errors). The flash intensity (normalised to impactor mass) scaled with impact speed to the power 5.5. However, the data also suggest that at constant speed the intensity scales with the area of the hole in the Kapton and not the projectile mass (i.e. with some property of the target and not as a function of the projectile energy or momentum). Using two layers of Kapton, it was possible to construct a Time of Flight (TOF) system, which used the time of the onset of the flash in each layer to produce flight speeds accurate to within typically 1%. When compared to the projectile speed pre-impact, there was no indication of projectile deceleration during passage through the Kapton film. In addition, when PVDF acoustic sensors were placed on the Kapton film, they exhibited an electromagnetic "pick-up" signal from the impact of projectile on the Kapton, confirming suspicions of signal interference from past work with acoustic sensors. The ability of the light flash to provide accurate impact timing signals suggests the TOF system would be suitable for use as a cosmic dust or debris impact detector in space (e.g. Low Earth Orbit). [ABSTRACT FROM AUTHOR]

This study investigates the properties and performance of bismuth ferrite thin films on Kapton sheets as electromagnetic (EM) wave-absorbing materials. The main techniques employed in this study involved modifying the surface geometry and using electromagnetic wave-absorbing materials as surface coatings. X-ray diffraction analysis revealed a cubic crystal structure of the bismuth ferrite thin films. The bonding analysis showed the presence of Bi–O and Fe–O functional groups at 432.26 and 519.48 cm−1, respectively. Vibrating-sample magnetometry revealed the ferromagnetic behavior of the bismuth ferrite thin film, confirming that saturation magnetization decreased with increasing sputtering time. Moreover, the calcination temperature affected the coercive field; the higher the calcination temperature, the higher the coercivity of the BiFeO 3 (BFO) thin film layer. Scanning electron microscopy with energy-dispersive X-ray spectroscopy of the bismuth ferrite thin films revealed the presence of Bi, Fe, and O—evenly and homogeneously distributed on the Kapton surface. After the ion implantation process, the atomic force microscopy test results showed an increased root-mean-square roughness (R q). The root-mean-square roughness value for Kapton before the process was approximately 7.5 nm, while the root-mean-square roughness values for BFO 10 min and BFO 12.5 min were approximately 18.8 nm and 25.3 nm, respectively. The microwave absorption ability reached a maximum reflection loss value of − 40.4 dB (99.9 %) in the range of 9.98 GHz with a sputtering duration of 10 min. Therefore, these results suggest bismuth ferrite is a potential candidate as an EM wave absorber. [ABSTRACT FROM AUTHOR]

This work reports the growth of stable TiO2 nanotube arrays on flexible Kapton substrates by electrochemical anodization of a sputtered Ti (titanium) film. Although such nanotubes are conventionally fabricated on Ti foils, obtaining these on polymer-based flexible substrates remained a challenge because of higher annealing temperature not compatible with thermal stability of the substrates. Here, we demonstrate the fabrication of TiO2 nanotubes (1.5 μm long and 80 nm diameter) by anodization of the Ti film deposited using the RF sputtering technique at two different substrate temperatures (room temperature and 300 °C). Nanoindentation and nanoscratch techniques reveal better adhesion of the Ti film with an underlying Kapton substrate for 300 °C deposition temperature. Such investigations reveal a more than twofold enhancement of the "rear pileup" for the Ti film deposited at elevated temperature compared to that at room temperature. The amorphous TiO2 nanotubes are crystallized at 220 °C for 3 h using a solvothermal technique that allows crystallization at temperatures much lower than the annealing temperature. Application of these nanotubes for photo-electrochemical water splitting reveals a photocurrent density of 18 μA/cm2 under AM 1.5 G conditions. Furthermore, the charge density and flat band potential (VFB) are calculated from Mott–Schottky analysis, showing features comparable to the TiO2 nanotubes on the Ti foil crystallized through thermal annealing. The present work establishes a scalable approach for developing TiO2 nanotube arrays on the flexible substrate and its use for photo-electrochemical solar energy conversion. [ABSTRACT FROM AUTHOR]

Flexible and economic sensor devices are the focus of increasing interest for their potential and wide applications in medicine, food analysis, pollution, water quality, etc. In these areas, the possibility of using stable, reproducible, and pocket devices can simplify the acquisition of data. Among recent prototypes, sensors based on laser-induced graphene (LIGE) on Kapton represent a feasible choice. In particular, LIGE devices are also exploited as electrodes for sensing in liquids. Despite a characterization with electrochemical (EC) methods in the literature, a closer comparison with traditional graphite electrodes is still missing. In this study, we combine atomic force microscopy with an EC cell (EC-AFM) to study, in situ, electrode oxidation reactions when LIGE or other graphite samples are used as anodes inside an acid electrolyte. This investigation shows the quality and performance of the LIGE electrode with respect to other samples. Finally, an ex situ Raman spectroscopy analysis allows a detailed chemical analysis of the employed electrodes.

Degradation in Kapton foil after gamma irradiation at low fluence is presented. These foils are irradiated for doses ranging from 10 to 500 kGy. The irradiated (10–50 kGy) Kapton foils show an uniform increase in visible absorption from 500 to 800 nm that decreases for further irradiation up to 500 kGy. FTIR spectra show first decrease in the absorption for all the peaks from 10 to 50 kGy and then increase from 50 to 500 kGy irradiation. Absorption of water moisture has also been observed at low fluence (∼10 kGy) that decreases at higher doses of irradiation. Difference spectra of Kapton before and after irradiation show chain scission at low fluence. This chain scission creates various types of defects, radicals and color centers. The reorganization/cross-linking of bonds is found at higher doses (>50 kGy) of irradiation, where the moisture absorbed at low doses of irradiation plays an important role. The Kapton foil shows opposite nature in terms of chain scission and cross-linking in comparison to the Poly (methyl methacrylate) irradiated in similar conditions. [ABSTRACT FROM AUTHOR]

PEPITES is a new type of transparent beam profiler (<10 µm water-equivalent thickness (WET)) under development that will equip the beam line of the ARRONAX cyclotron. Segmented electrodes consisting of nanometric thick gold strips deposited on a thin polymer membrane make the active part. In order to characterize the damages induced in the polymer, UV–Vis spectroscopy and scanning electron microscope have been used on 8 μm thick Kapton polyimide membranes irradiated with 68 MeV proton beams up to 7 × 1015 H+/cm2. Dynamic and permanent damage was observed only at a high fluence level, thus ensuring long-term operation of the PEPITES detector in its nominal working environment. [ABSTRACT FROM AUTHOR]

Indirect recoil implantation following a nuclear reaction is a technique used to activate the surface of materials that cannot be directly activated by a charged particle beam. This research focuses on the indirect activation of Kapton® foils, which serves as a model of plastic or plastic coated surface activation. The alpha particle primary beam, produced by a cyclotron accelerator hits a stack of titanium and Kapton® interlaced foils. The implanted activity in the Kapton® foils is presented as a function of the primary beam energy for two separate implanted radioisotopes 51Cr and 48V, having suitable nuclear parameters for tracing in engineering experiments. [ABSTRACT FROM AUTHOR]

Contact electrification is a direct triboelectrification method for producing current through charge transfer when two different differentiated materials have brought into contact. For the first time, we developed a simple triboelectric nanogenerator (TENG) where the electronic charges were realized through contact separation mode between sand-polished Kapton (SPK) and Al surface. Here, we demonstrated the energetic interfacial contact between these surfaces and observed satisfactory output performance. The novel SPK-TENG produced 40 V and 2.8 µA, of open-circuit voltages (Voc) and short-circuit currents (Isc) at 4 Hz, respectively. Mainly, the SPK-TENG was dramatically increased up the performance of TENG, up to 40% of Voc and 42% of Isc, with respect to the Kapton film because the mobility of electrons is very high on the device surface compared to the other pristine Kapton film. The fabricated SPK-TENGs were good candidates for satisfying the need for alternative contact separation mode TENGs. [ABSTRACT FROM AUTHOR]

We aim to determine the detection threshold of Kapton as an Etched Track Detector irradiated with 345 MeV/u U ion, as well as other several heavy ions of Al, Si, Ar, Kr and Xe. The heavier ions are found to have higher detection threshold in the stopping power. At the same stopping power, the track registration sensitivity decreases with increasing the nuclear charge of ions. U ion has the lowest sensitivity as S = 0.04 at the detection threshold of 3400 keV/μm. We have updated the conventional radial dose distribution theory using a relatively new experimentally supported formula for the effective charge up to U ion. The local doses at a track radius of 0.8 nm, which is half of the length of a repeat unit of Kapton, is useful to understand the relation between the sensitivity of heavy ions and the stopping power at each detection threshold. [ABSTRACT FROM AUTHOR]

Digital microfluidics (DMF) devices enable precise manipulation of small liquid volumes in point-of-care testing. A printed circuit board (PCB) substrate is commonly utilized to build DMF devices. However, inkjet printing can be used to fabricate DMF circuits, providing a less expensive alternative to PCB-based DMF designs while enabling more rapid design iteration cycles. We demonstrate the cleanroom-free fabrication process of a low-cost inkjet-printed DMF circuit. We compare Kapton and polymethyl methacrylate (PMMA) as dielectric coatings by measuring the minimal droplet actuation voltage for a range of actuation frequencies. A minimum actuation voltage of 5.6 V was required for droplet movement with the PMMA layer thickness of 0.2 μm and a hydrophobic layer of 0.17 μm. Significant issues with PMMA dielectric breakdown were observed at actuation voltages above 10 V. In comparison, devices that utilized Kapton were found to be more robust, even at an actuation voltage up to 100 V.

Purpose: We developed a new class of aerogel‐based thin‐film self‐powered radiation sensors employing high‐energy electron current (HEC) in periodic multilayer (high‐Z | polyimide aerogel (PA) | low‐Z) electrode microstructures. Materials: Low‐Z (Al) and high‐Z (Ta) electrodes were deposited on 50 μm‐thick PA films to obtain sensors with Al‐PA‐Ta‐PA‐Al structures. Sensors were tested with x rays in the 40–120 kVp range and with 2.5 MV, 6 MV, and 6 MV‐FFF linac beams (TrueBeam, Varian). Performance of PA‐HEC sensors was compared to commercial A12 Farmer ionization chamber as well as to radiation transport simulations using CEPXS/ONEDANT with nanometer‐to‐micrometer spatial resolution. The computations included periodic and single‐element structures N x (Al‐PA‐Ta‐PA‐Al) with variable layer thicknesses. Results: Signal from PA‐HEC sensors was proportional to the simulated net leakage electron current (averaged over the PA thickness). Experimental response was linear with dose and independent of dose rate. Detector responses to different x‐ray sources show higher signals for kVp photon energies, as expected, though a strong signal was obtained for MV energies as well. The signal scaled with total effective area inside the multielemental structures; for example, the yield of a multielement sensor made with 20 Ta layers compared to a single‐element structure with 1 Ta layer of the same total thickness of Ta was 10 times greater for 6 MV beam and 23 times greater for 120 kVp. Beam attenuation per element in the detector was 0.5%, 1%, 3%, and 46%, respectively for 6 MV, 6 MV FFF, 2.5 MV, and 120 kVp. Conclusion: We demonstrated the feasibility of aerogel‐based multilayer HEC radiation detector and its application for flux/dose monitoring of kVp and radiotherapy MV beams with small beam attenuation. [ABSTRACT FROM AUTHOR]

Harvesting mechanical energy from daily life human activities has gained tremendous interest, along with the concept of waste to wealth which has been also a major concern from a few decades. In this regards, firstly, we fabricated microcrystalline cellulose (MCC) particles from the squandered cotton and they were further dissolved into biocompatible polyvinyl alcohol (PVA) to develop a triboelectric material. The resultant cellulose loaded PVA film (CPF) was employed as a positive triboelectric material to design a coin-cell type TENG, whereas the Kapton was used as a negative material. Design of such TENG using CPF can reduce the processing cost and is also significant to incorporate the waste cotton into an energy harvesting device. Besides, the effect of electrical output performance of CPF-based prototype TENG (CPF- p TENG) as a function of the concentration of MCC particles loaded into PVA was also systematically studied and optimized. Thus, the CPF- p TENG with the 2.5 wt% of cellulose added into PVA exhibited a stable and high electrical output. The electrical performance of CPF- p TENG was further enhanced by introducing the microarchitectures on the surface of CPF, and it exhibited comparatively very high voltage, current and power density values of ∼600 V, 50 μA and 84.5 W/m2, respectively. Finally, to demonstrate the practical or commercial applications, a MACPF-based coin-cell type TENG (i.e., MACPF- cc TENG) was developed to harvest the mechanical energies available in daily human life by placing it under the human-foot medial arch, which can be further utilized as a self-power system to drive various portable electronics. Image 1 • We reported a dynamic conversion of squandered cotton into microarchitectured triboelectric films with low processing cost. • Using these films, a coin-cell type TENG was fabricated, which exhibited a high and durable electrical output. • Such coin-cell type TENG was placed under medial arch of human foot to harvest various human actions. • Human foot medial arch was first time proposed as the perfect location for the coin-cell type TENG. • It also employed as a self-powered system to drive various portable electronics. [ABSTRACT FROM AUTHOR]

A project to investigate space environment effects on specific materials with interest to remote sensing was initiated in 2016. The goal of the project is to better characterize changes in the optical properties of polymers found in multi-layered spacecraft insulation (MLI) induced by electron bombardment. Previous analysis shows that chemical bonds break and potentially reform when exposed to high energy electrons like those seen in orbit. These chemical changes have been shown to alter a material's optical signature, among other material properties. This paper presents the initial experimental results of MLI materials exposed to various fluences of high energy electrons, designed to simulate a portion of the geosynchronous Earth orbit (GEO) space environment. In situ optical reflectivity measurements are presented before, during and after electron dosing. It is shown that the spectral profile of some of the tested materials changes as a function of electron dose. These results provide an experimental benchmark for analysis of aging effects on satellite systems which can be used to improve remote sensing and space situational awareness. They also provide preliminary analysis on those materials that are most likely to comprise the high area-to-mass ratio (HAMR) population of space debris in the geosynchronous orbit environment. Finally, the results presented in this paper serve as a proof of concept for simulated environmental aging of spacecraft polymers that should lead to more experiments using a larger subset of spacecraft materials. [ABSTRACT FROM AUTHOR]

Abstract Large, thin, prestressed membranes known as 'gossamer' structures have many applications in space, including light reflection and electromagnetic signal collection. The prestress forces applied to these structures usually causes some wrinkling of the membrane to occur, and the degree of wrinkling affects the reflective performance of the structure. The primary aim was to assess whether solar radiation pressure could affect the wrinkle pattern of gossamer structures, with a particular focus on solar sails. Several prestressed rectangular membranes with dimensions and material properties representative of current and future solar sails, a class of membrane structures typically made of Kapton, were modelled to investigate the effects of pressure on the wrinkle pattern. It was shown that increasing the pressure applied normal to the membrane surface increased the amplitude and decreased the wavelength of the wrinkles. However, no significant change in the wrinkle pattern was found to occur until the magnitude of the applied pressure was much greater than that likely to be experienced by gossamer structures due to solar radiation pressure. Therefore it was concluded that the effects of solar pressure will have no significant impact on the future development of larger and thinner gossamer structures than exist at present. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cleavage of polyimide upon impact by atomic oxygen can be divided into three stages. • Under the impact of atomic oxygen, the protective coating protects the substrate much better than the mixed filler material. • The protective effect of the SiO 2 protective coating is superior to that of graphene due to its serrated structure. • Sio 2 absorbs and stores incident atomic oxygen and reacts with subsequent incident atomic oxygen. KAPTON-type polyimide (PI) is a crucial polymer that is often used in the aerospace industry, but the high levels of atomic oxygen (AO) in low-earth orbit (LEO) can cause the polymer to deteriorate and peel, so it is especially important to protect PI from AO. Incorporating nano-reinforcements into PI and applying a protective coating to the surface of PI are the two basic strategies for shielding PI from AO impact. Herein, to investigate the effect and mechanism of different protection methods, molecular models of PI reinforced with graphene (Gr) and carbon nanotubes (CNTs) as well as covered by silica (SiO 2) and Gr, respectively, are constructed. Reactive molecular dynamics simulations are then performed to explore the degradation mechanisms of PI under AO impact. Results indicated that the addition of CNT and Gr can improve the resistance of PI to AO erosion, and their protective effect is mainly by burying in the PI substrate to prevent the penetration of AO downward. Additionally, the protective effect of covering the PI surface with a protective layer is significantly better than that of mixing nanomaterials into the PI substrate. Meanwhile, the protective effect of the Gr protective layer is weaker than that of SiO 2 due to its smooth surface, which tends to slip when AO is incident, and it plays a protective effect mainly by bouncing the incident AO. By comparison, the SiO 2 protective layer can be embedded into the substrate due to its serrated structure, which better protects the substrate, and it protects the substrate mainly by absorbing the incident AO. This study provides useful guidance for the identification of promising candidate materials for LEO applications, as well as for the development of molecular design for AO-resistant polymeric materials. [ABSTRACT FROM AUTHOR]

It is a challenge to simultaneously achieve a high selectivity and permeance for the glassy polymeric membranes. Herein, the asymmetric Kapton membrane fabricated by pyromellitic dianhydride and 4,4′-oxydiphenylenediamine was prepared by the phase inversion method and characterized by rheometer, SEM, TGA, FT-IR and tensile testing. The aim of this work is to enhance gas separation performance of the membrane and its application value via optimizing the concentration of acetone additive, coagulation bath composition and evaporation time. After optimizing, results showed that the transition from the instantaneous coagulation to the delayed coagulation, and the inner membrane structure is gradually transferred from the finger-like shape to the sponge-like shape. The optimized gas separation performance of the resulting Kapton membrane has the permeance of 2.49 GPU and 1.10 GPU for H 2 and CO 2 , respectively, as well as selectivity of 57.07 and 25.27 for H 2 /CH 4 and CO 2 /CH 4 , respectively. [Display omitted] • A facile phase inversion method for the fabrication of a high-performance asymmetric Kapton membrane. • A defect-free membrane structure was prepared by the optimization of a series of operation parameters. • A high permeance of 2.49 GPU and 1.10 GPU for H 2 and CO 2 , respectively. • A high selectivity of 57.07 and 25.27 for H 2 /CH 4 and CO 2 /CH 4 , respectively. [ABSTRACT FROM AUTHOR]

Since the Triboelectric Nanogenerator (TENG) was invented in 2012, Its potential in the area of energy generation and self-powered sensors has been very obvious, one of the uses of TENGs is as self-powered touch buttons, which are usually single-electrode TENGs, single-electrode TENGs are made of a layer of a material (which is to be triboelectrified) attached to an electrode which is connected to an electrical ground or a reference electrode, in this study, a cheap triboelectric button was made with Kapton and tested in contact and separation with aluminum and a human finger while varying parameters such as the grounding state of the person touching the button and the touch force. It was found that the tested button gave easily detectable signals if touched with aluminum foil or a human finger, however, the signal to noise ratio was low in case of being pressed by a human finger with the person touching the button also being grounded, this is due to an increased capacitance between the person pressing the button and the environment, it was also found that the output voltage of the TENG increased after pressing it lots of times consecutively due to an increased amount of total charge on the Kapton layer when pressed at slightly different spots, these output characteristics could help in better integration of such buttons in human-machine interaction applications. [Display omitted] • A TENG button was tested under various conditions. • The button was able to provide detectable signals in multiple test cases. • The signal-to-noise ratio was low if the person pressing the button was grounded. • The voltage output of the button increased after being pressed a lot of times consecutively. [ABSTRACT FROM AUTHOR]