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The engraving of CO2 laser on polyimide Kapton sheet will directly generate porous graphene, which is suitable for supercapacitor applications. The possibility of a combination of biopolymer electrolytes with Laser-Induced Graphene (LIG) is investigated. The prepared LIG is characterized by X-Ray Diffraction (XRD) analysis and Raman spectroscopy techniques. The biopolymer electrolyte was prepared by solution casting method, and the conductivity of the film is analysed. The supercapacitor was fabricated using LIG as electrode and biopolymer-ionic liquid combination as electrolyte. The resulting capacitor has a specific capacitance of 54.28Fg−1. This particular combination of the LIG electrode-biopolymer electrolyte combination is suitable for supercapacitor applications.

In this work, we propose and demonstrate a carbon nanotube (CNT) field-effect transistor (FET) based biosensor for selective detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). CNT FETs were fabricated on a flexible Kapton substrate and the sensor was fabricated by immobilizing the reverse sequence of the 25-base portion of the RNA-dependent RNA polymerase gene of the SARS-CoV-2 onto the CNT channel. The biosensors were tested for the synthetic positive and control target sequences. The biosensor showed a selective sensing response to the positive target sequence with a limit of detection of 10 fM. The promising results from our study suggest that the CNT FET based biosensors can be used as a diagnostic tool for the detection of SARS-CoV-2.

The Lunar Laser Ranging Retro-reflectors (LRR) allow for the precise measurement of the travel time of laser pulses from the Earth to the lunar surface and back. Dust accumulation on the LRRs scatters the reflected light used for laser interferometry measurements leading to a reduction in the return signal amplitude by a factor of ≃ 10. We report on a series of experiments utilizing a method of an iterative application and removal of an acrylic adhesive kapton tape to remove lunar dust simulant from a glass substrate. The effectiveness of adhesive tape was determined by measuring the transmission of an expanded laser beam through a glass substrate with a dusted surface. Calibration data was obtained before the glass was exposed to any dust, and light transmission was measured after each iteration of adhesive removal using a power meter. The procedure was repeated using heavy gloves while keeping the glass substrate at 120 ° C to simulate the temperature conditions of a lunar day on the surface. A third test was conducted at room temperature in high-vacuum to ensure functionality in the lunar environment. These experiments show that glass substrates can be restored to 98 ± 2 % of their original transmission using the adhesive tape method. Therefore the light that travels into and out of the quartz surface of the LLRs can be restored up to 96 ± 4 % of their initial transmission.

Cross sections of alpha-particle induced reactions were determined on antimony targets using alpha-particle irradiation with a primary energy of 50 MeV. The standard stacked target technique, activation method and offline gamma-ray spectrometry were applied for determination of the reaction cross sections. Thin Sb targets prepared by vacuum evaporation onto Kapton backings were activated. Ti foils were inserted into the stack for monitoring the alpha-particle beam parameters and energy loss of the particles in the target by using the natTi(α,x)51Cr monitor reaction. Reaction cross sections for formation of 121,123,124,125,126I, 121m,g,123m,125mTe and 118m,120m,122gSb were determined and compared to the available literature data and theoretical estimation of the cross sections from the TENDL-2019 data library.

A free-standing high boron-doped diamond nanosheet (BDDNS) has been fabricated for the development of a flexible BDDNS strain senor. High boron-doped diamond was initially grown on a tantalum substrate in a microwave plasma-assisted chemical vapor deposition method, and was then transferred to a Kapton polymer substrate to fabricate the flexible BDDNS/Kapton device. Before performing the transfer process, the thin BDDNS’s morphology and bonding structure on the top and bottom surfaces were investigated using scanning electron microscopy and Raman spectroscopy. The contact potential difference and work function values of the BDDNS top and bottom surfaces were measured using a Kelvin probe atomic force microscope. Significant electrical conducting properties were observed from the resistance mapping of the BDDNS foil, and the average resistance value of 31 Ω attained from the top surface of the BDDNS foil. The electrical response of the BDDNS/Kapton device was investigated using a custom-made measurement system and a positive residual resistance change with strain was observed. The developed BDDNS/Kapton device was able to sustain for measuring up to 0.55% of strain, which indicates it may have great potential to be utilized in low-strain sensor applications.

Spacecraft operating in low-Earth orbit are subjected to a number of hazardous environmental constituents that can lead to decreased system performance and reduced operational lifetimes. Due to their thermal, optical, and mechanical properties, polymers are used extensively in space systems; however they are particularly susceptible to material erosion and degradation as a result of exposure to the LEO environment. The focus of this research is to examine the material erosion and mass loss experienced by a custom Kapton-like polyimide due to exposure in a simulated low-earth orbit environment. The deployable membrane telescope design discussed in this research is named Peregrine and is the scientific payload for FalconSat-7, a 3U cubesat designed and developed at the United States Air Force Academy (USAFA) for the purpose of demonstrating the capability of deployable membrane telescope technology on a nano-satellite platform. In addition to the polymer samples, chrome, silver and gold specimens will be examined to measure the oxidation rate and act as a control specimen, respectively. A magnetically filtered atomic oxygen plasma source has previously been developed and characterized for the purpose of simulating the low-Earth orbit environment. The plasma source can be operated at a variety of discharge currents and gas flow rates, of which the plasma parameters downstream of the source are dependent. The characteristics of the generated plasma were examined as a function of these operating parameters to optimize the production of O+ ions with energy relevant to LEO applications. The erosion yield of the Kapton-like polyimide was experimentally determined to be 2.84 × 10−24 cm3 per atom which is in close agreement when compared to the on-orbit measurement for reaction efficiency of Kapton HN. The experimentally determined reaction rate for the Kapton-like polyimide was used to estimate the operational lifetime of the photon sieve during the solar conditions expected beginning in May 2019. The effective lifetime is estimated between 126 and 153 days.

This paper discusses the DC power distribution topology by means of laminated busbar for medium power applications such as energy storage systems in electric vehicles. The optimized power distribution for laminated busbar is compared for materials such as copper, aluminum and Gold. The loop Inductance and capacitance are major parameters that are designed based on the length, width, thickness of the materials and insulation material electrical and physical properties. Besides the paper also discuss the variation of the dielectric materials such as epoxyglass, Kapton, nomex and Mylar. The simulation results have done in Ansys simulation software and they are compared with the analytical results. The power distribution in EV’s using converters has high electromagnetic emissions which can be decreased by extending the busbar obtained here to the inverter in EV’s where volume and weight are key factors along with the inductance and capacitance.

Triboelectric nano-generators (TE-NGs) can be utilized as a power supply for wireless systems, sensors, and operators. In this paper, new flexible TE-NGs that use sodium carboxymethyl cellulose (CMC), poly dimethyl siloxane (PDMS), polyvinylidene fluoride (PVDF), poly (4,4′-oxydiphenylene-pyromellitimide) (KAPTON) films and also sugar as a piezoelectric material were developed and are reported. Also, the outputs of NGs made by linear power under a periodic pressure of ~ 0.2 MPa at a frequency of 3 Hz showed that the highest output of NGs are related to PDMS–KATTON, PDMS, PVDF–KAPTON, PVDF, CMC NGs, respectively. It has been also observed that NGs connected in series to each other have a higher output than paralleled NGs so that their voltages increase at higher frequencies. Besides, a significant point is that the NGs are made in a low-cost, affordable, and environmentally-friendly route, which is a superior characteristic with respect to the rest of the NGs.

This work discusses an analysis of laser beam characteristics, applied to conduction welding of AZ92A magnesium wires for medical meshes. Our experiments consisted of the exposure of multiple laser shots on kapton film varying focal position and laser power. Our results indicate that a high laser power level promotes a linear increase of beam radius at focal plane, quality factor and divergence angle. A parametric analysis was carried out varying input energy levels. Porosity was observed as a defect owing to high magnesium reactivity with oxygen. A direct relation of input energy and weld spot size was observed.

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.

Rationally engineering three dimensional (3D) architrctures of transition-metal oxides (TMOs) is of great concern for the effective enhancement of electrochemical capacity, nevertheless, it is still challenging to selectively construct well-defined 3D architectured electrode materials in planar-configuration supercapacitors (SCs). Herein, we demonstrated a novel 3D nanotube-structured Ni@MnO2 electrode with interdigital configuration for high-performance planar supercapacitors. By combining transfer printing, alloying-dealloying and electrodeposition methods, 3D architecture of nanotube-structured Ni@MnO2 was subtly built on flexible Kapton substrate. The highly conductive Ni nanotubes embedded in MnO2 nanoflakes offer efficient electron collection paths, endowing the 3D electrodes with low internal resistance. Simultaneously, this 3D nanotube architecture provides multiple channels for electrolyte penetration and large active surface for Faradaic reactions. For these reasons, 3D SCs deliver remarkably enhanced areal capacitance of 10.75 mF cm−2, 2.4 times of the pristine SCs without 3D architecture. Moreover, 3D SCs exhibit desirable flexibility under different bending conditions, which indicates the potential feasibility of planar-configuration SCs as energy-storage components for wearable electronics.

Multi-layer insulation (MLI) blankets are one of the main components of satellite thermal control system. The past studies have considered infinite heat transfer coefficient in modeling the MLI shields due to the use of reflective thin films such as aluminized Kapton (Polyimide Film Developed by DuPont Company) or aluminized PET (Polyethylene Terephthalate) in MLI shields. Therefore, equal temperature was considered on two sides of a shield and the effect of thermal resistance has been ignored in the total thermal resistance. In the present study, the effects of thermal conductivity of thin film and shield thickness are analyzed. For this purpose, numerical analyses are performed on three types of blankets that are made of Kapton, PET and null shields. The results indicate that the difference in effective emittance of Kapton and PET blanket is 17% to 2% from the thinnest film to the thickest film, respectively. In order to confirm the numerical results, the effective emittance of two types of MLI blankets made of Kapton and PET films is measured under identical conditions. It is concluded that the Kapton blanket has lower effective emittance than PET.

Polyimides, particularly poly-(pyromellitic dianhydride-4,40-oxydianiline) or PMDA-ODA (Kapton-H®), are ubiquitous in the aircraft and aerospace industries, flexible printed circuits, and many other high-performance applications. For many of these applications, the polymer's stability during and after radiation damage is a serious concern. The effect of electron irradiation on the breaking of inter-molecular bonds and creation of free radicals in Kapton polyimide were studied using reactive molecular dynamics simulation with the polarizable ReaxFF method and experimentally on pristine and electron irradiated polyimide by vibrational spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, wide angle x-ray diffraction, small angle x-ray scattering, and dynamic mechanical analysis. In our simulations, the electron beam is approximated by a dense column of negatively charged particles, which is inserted at random positions in the polyimide matrix. In order to observe inter-molecular bond breaking during the time frame of the molecular simulations, each electron beam is switched on for 2 fs, causing an average energy of 21 eV per electron trajectory to be transferred to the polyimide through Coulomb interactions during the simulation. Experimentally, polyimide is aged in vacuum with a 90 keV electron beam with a maximum penetration depth greater than the material's thickness. Throughout the simulations, modifications in the chemical structure of the polyimide during and after the electron beam irradiations are monitored. During electron beam irradiation, hydrogen atoms separate from different parts of the polyimide through C–H bond cleavage. After turning off the electron beams and running a microcanonical molecular dynamics simulation for 0.5 ns, several chemical and structural rearrangements are observed in the polyimide structure. The chemical modifications mostly include ring opening and other changes to the imide rings. The computations are compared to infrared spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, x-ray scattering, and mechanical measurements on aged and pristine polyimide to both guide and validate the conclusions from the computational study. Apart from these changes in chemistry we also evaluate temperature evolution and change in mechanical response of the polyimide slab caused by electron beam exposure. Taken together, the direct measurements of the electronic, chemical, and mechanical properties of the irradiated Kapton films validate the key results of the model.

The exploration of multifunctional perovskite nanostructures for flexible sensor/energy harvesting applications is of great interest. Herein, highly crystalline ferroelectric Bi4Ti3O12 nanoparticles (NPs) were brush-coated onto flexible Kapton film without using costly instrumental techniques or polymer templates. Moreover, flexible ferroelectric high-temperature thermistors (FHTTs) having high thermal sensitivity (β(100/260) = 6515 K) and a broad working temperature range (25–260 °C) were developed based on bismuth-layered perovskites. Polarization (P) vs. Electric field (E) (P–E) loops of the orthorhombic phase of Bi4Ti3O12 NPs were measured at different frequencies under poled and unpoled conditions. The Bi4Ti3O12 NPs exhibited a multi-fold improvement of remnant polarization (Pr ≈ 6 μC/cm2) at the coercive field (Ec ≈ 90 kV/cm) over that previously reported. Lastly, the prototype of a self-powered-FHTT was fabricated, which could be used as an efficient environmental temperature warning/monitoring system free of complex battery sources. The Bi4Ti3O12 NPs/PVDF composite film-based piezoelectric nanogenerator (BPCF-PNG) used an eco-friendly power source (generating 12.7 mW/m2 at 300 MΩ upon 4 N applied force) to drive the FHTT. The brush-coating method to prepare flexible ferroelectric films is highly suitable for large-scale fabrication, and is also an eco-friendly and time-efficient process. The detailed investigation reported herein is a novel approach to next-generation ferroelectric-based sensors, memristors, and energy harvesters.

The measurement of pH value of solutions is crucial in many fields of modern science. We deposited MWCNTs coating on a planar capacitive structure consisting of interdigitated gold and aluminium electrodes on a flexible Kapton foil substrate, to develop the pH sensors. MWCNTs coating acts as an H+ ion sensing layer. The complete structural, mechanical and electrical characterization has been performed. The sensors involve supplying gold/aluminium electrodes with an input voltage and measuring the changes in the capacitance, resistance and impedance when the sensor chip is exposed to different pH solutions. The experimental setup was built for dipping the sensors in the sample liquids of different pH values from 4 to 9, being very flexible, reproducible and robust.

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-pTENG) as a function of the concentration of MCC particles loaded into PVA was also systematically studied and optimized. Thus, the CPF-pTENG with the 2.5 wt% of cellulose added into PVA exhibited a stable and high electrical output. The electrical performance of CPF-pTENG 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-ccTENG) 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.

Modern electronic systems are smarter and compact, yet highly efficient at greater speeds. These systems require just a minimal amount of power which have indeed encouraged new technologies to scavenge energy from the surrounding environment. Triboelectric nanogenerator (TENG) is one such device which has demonstrated a cost-effective, reliable and efficient technology for harvesting natural mechanical energy. However, the durability and stability of TENG is a critical attribute for the high output efficiency at a consistent rate and strongly depends on the frictional characteristics of triboelectric materials. In the first of its kind, a detailed investigation is done on the ability of diamond-like carbon (DLC) film to be a potential triboelectric material for TENG applications. DLC film was deposited on the substrate (electrode) of a contact-separation based TENG (CS-TENG) using plasma-based ion implantation and deposition (PBII&D) technique. The performance evaluation of TENG consisting of DLC film - polymer as the triboelectric pairs revealed some very interesting results. Hydrogenated DLC (H-DLC) and PTFE (Polytetrafluoroethylene) based TENG produced the highest output with a peak current of 3.5 μA and a power density of up to 57 mW/m2 over other conventional dielectric pairs like Al-PTFE, Polyimide (Kapton®)-PTFE, and Kapton-Al. Furthermore, fluorine doped DLC (F-DLC) film produced a moderate output with Kapton, and PTFE, indicating its benefits for TENG applications. In the durability assessment, the DLC deposited rotary sliding-TENG exhibited excellent durability by producing a stable output current for 3 h at a reduced friction coefficient. This study serves as a noteworthy beginning towards the understanding of the triboelectric behavior of DLC films from TENGs perspective and could significantly contribute to designing of a highly durable, cost-effective, low friction and efficient sliding-TENG.

The application, continued performance, and degradation behavior of polymers often depends on their interaction with small organic or gaseous volatiles. Understanding the underlying permeation and diffusion properties of materials is crucial for predicting their barrier properties (permeant flux), drying behavior, solvent loss or tendency to trap small molecules, as well as their interaction with materials in the vicinity due to off-gassing phenomena, perhaps leading to compatibility concerns. Further, the diffusion of low Mw organics is also important for mechanistic aspects of degradation processes. Based on our need for improved characterization methods, a FTIR-based spectroscopic gas/volatile quantification setup was designed and evaluated for determination of the diffusion, desorption and transport behavior of small IR-active molecules in polymers. At the core of the method, a modified, commercially available IR transmission gas cell monitors time-dependent gas concentration. Appropriate experimental conditions, e.g. desorption or permeation under continuous flow or static gas conditions, are achieved using easily adaptable external components such as flow controllers and sample ampoules. This study presents overview approaches using the same IR detection methodology to determine diffusivity (desorption into a static gas environment, continuous gas flow, or intermittent desorption) and permeability (static and dynamic flow detection). Further, the challenges encountered for design and setup of IR gas quantification experiments, related to calibration and gas interaction, are presented. These methods establish desorption and permeation behavior of solvents (water and methanol), CO2 off-gassing from foam, and offer simultaneous measurements of the permeation of several gases in a gas mixture (CO2, CO and CH4) through polymer films such as epoxy and Kapton. They offer complementary guidance for material diagnostics and understanding of basic properties in sorption and transport behavior often of relevance to polymer degradation or materials reliability phenomena.

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.

The flammability limits of thin flame retardant materials in an opposed flow under microgravity condition have been discussed by scale analysis. The predicted trends of flammability were verified by parabolic flight experiments. As the samples, meta- and para-aramid fabrics (NOMEX and Kevlar), polyimide film (Kapton) and polycarbonate (PC) were investigated. In order to predict the limiting curve accurately, blow-off tests in high forced flow were conducted and the results were used to obtain proper pre-exponential factor, A, and activation energy, E, for blow-off phenomena. The blow-off tests revealed that the material with high pyrolysis temperature, such as Kevlar and Kapton, had its minimum limiting oxygen concentration (MLOC) at higher opposed velocity region. For such materials, it was predicted that the limiting oxygen concentration in microgravity environments was higher than that in normal gravity, and the prediction was consistent with the result of parabolic flight experiment. For NOMEX and PC, the limiting oxygen concentration increased monotonically with increase of opposed flow velocity. The developed model predicted that such materials could have their MLOC in microgravity environments. Actually, the MLOCs of NOMEX and PC were observed under microgravity condition and they were 2% and 0.5% lower than their limiting oxygen concentrations in normal gravity (LOC1g), respectively. The developed model with blow-off test data could predict the difference between the MLOC and LOC1g quantitatively, and it was found that the model was a good tool to discuss the flammability of the flame retardant materials in microgravity environments.

Embedded piezoelectric lead zirconate titanate (PZT) transducers in carbon fibre reinforced plastic (CFRP) composites are typically electrically insulated by interlaying materials such as polyimide Kapton films between the PZT and the laminate ply. However, the presence of polymeric films may cause debonding at the layer interface, thus reducing the structural performance. This paper proposes an alternative insulation technique in which PZTs are covered by a thin patch of woven E-glass fibre fabric for enhanced adhesion with the surrounding epoxy matrix. An analysis of variance on experimental test results showed that the compressive, flexural and interlaminar shear strengths of plain CFRP specimens were equal to the means of the smart CFRP composite (0.41 < p-value < 0.58), but significantly higher than those of Kapton specimens (0.0001< p-value < 0.05). Moreover, a post-test fractographic analysis indicated that damage opening in Kapton specimens was significantly larger (p-value = 0.03) than that in plain specimens. Brooming failure compression was also the same for the smart CFRP composite and plain samples, whereas Kapton specimens failed by through-thickness shear. Finally, nonlinear ultrasonic experiments were conducted on CFRP laminates with artificial in-plane delamination using glass fibre insulated PZTs. Remarkably, the effect of second harmonic generation was found to be nearly two times higher than conventionally surface-bonded PZTs.

We report a stamp-assisted printing strategy to achieve interdigital electrodes with well-defined geometry and distinct nanotexture for flexible planar micro-supercapacitors (MSCs). Insulating ink pattern is imprinted on conductive glass with the assistance of stamp, serving as a mold for selective electroplating of Ni finger pattern. Combining this process with pattern transfer and electrodeposition procedures, well-defined interdigital Ni/MnO2 electrodes are constructed on flexible Kapton in an extremely simple, efficient and low-cost route without the use of complicated and costly microfabrication technologies. Furthermore, the as-formed Ni electrode fingers exhibit distinct nanotextured surface morphology, endowing the resultant Ni/MnO2 MSCs with high areal capacitance (4.15 mF cm−2), remarkably higher than that of texture-free Ni/MnO2 MSCs. More importantly, owing to the adoption of stamp-assisted printing technique, MSCs can be seamlessly integrated in series and parallel on one piece of chip without any external wires, well fulfilling the requirement of power suppliers with high voltage and large capacitance output for wearable electronics. This work opens up a feasible route for the fabrication and integration of high-performance flexible planar MSCs, and may find vast applications in relevant fields, such as lithium batteries, nanogenerators and sensors.

Recently, shape memory polymers (SMPs) with high optical transmittance have been paid great attentions to endow the flexible optoelectronics with shape memory functions. Herein, a low colored and transparent shape memory copolyimide (SMcoPI) is obtained by suppressing the charge transfer complex interactions. The optical transmittance of the synthesized SMcoPI film could reach at ∼86% at the wavelength of 450 nm, far higher than the nearly zero optical transmittance of yellow and brown Kapton H. The better optical transparency could be attributed to the loose molecular chain arrangements induced by the meta-substituted groups and flexible ether linkages. The glass transition temperature (Tg) range of the synthesized SMcoPI films is from 179 °C to 220 °C, which is higher than that of reported optically transparent SMPs. The effective decomposition temperature at the weight loss of 5 wt% is 517 °C, showing excellent thermal stability. The SMcoPI also demonstrated good shape memory behaviors with high shape recovery ratio (Rr, >96%) and shape fixity ratio (Rf, >97%). In addition, the SMcoPI could maintain high optical transmittance, good thermostability and excellent shape memory behaviors after the ground-stimulated space thermal cycling test for 250 h. The synthesized SMcoPI has application potentials in high temperature areas or optoelectronic devices.

Cu-Al-Ni and Cu-Al-Ni-Mn shape memory alloys are deposited on Kapton polyimide sheets by a physical evaporation technique. Detailed investigations on the morphological, structural and thermal behaviour of the ternary and quaternary alloys are conducted. The developed samples exhibit an increase in martensite structures and decrease in transformation temperatures after Mn additions. Furthermore, the suppression of Cu3Al precipitates was evident from XRD analysis. The thermomechanical behaviour was analysed by actuating the bimorphs through Joule heating under varying mechanical loads. Fatigue analysis of the bimorphs reveals a superior performance for Cu-Al-Ni-Mn, exhibiting less than 30% loss in displacement after 15,000 cycles.

A stack of thin Nb foils was irradiated with the 100 MeV proton beam at Los Alamos National Laboratory's Isotope Production Facility, to investigate the $^{93}$Nb(p,4n)$^{90}$Mo nuclear reaction as a monitor for intermediate energy proton experiments and to benchmark state-of-the-art reaction model codes. A set of 38 measured cross sections for $^{\text{nat}}$Nb(p,x) and $^{\text{nat}}$Cu(p,x) reactions between 40-90 MeV, as well as 5 independent measurements of isomer branching ratios, are reported. These are useful in medical and basic science radionuclide productions at intermediate energies. The $^{\text{nat}}$Cu(p,x)$^{56}$Co, $^{\text{nat}}$Cu(p,x)$^{62}$Zn, and $^{\text{nat}}$Cu(p,x)$^{65}$Zn reactions were used to determine proton fluence, and all activities were quantified using HPGe spectrometry. Variance minimization techniques were employed to reduce systematic uncertainties in proton energy and fluence, improving the reliability of these measurements. The measured cross sections are shown to be in excellent agreement with literature values, and have been measured with improved precision compared with previous measurements. This work also reports the first measurement of the $^{\text{nat}}$Nb(p,x)$^{82\text{m}}$Rb reaction, and of the independent cross sections for $^{\text{nat}}$Cu(p,x)$^{52\text{g}}$Mn and $^{\text{nat}}$Nb(p,x)$^{85\text{g}}$Y in the 40-90 MeV region. The effects of $^{\text{nat}}$Si(p,x)$^{22,24}$Na contamination, arising from silicone adhesive in the Kapton tape used to encapsulate the aluminum monitor foils, is also discussed as a cautionary note to future stacked-target cross section measurements. \emph{A priori} predictions of the reaction modeling codes CoH, EMPIRE, and TALYS are compared with experimentally measured values and used to explore the differences between codes for the $^{\text{nat}}$Nb(p,x) and $^{\text{nat}}$Cu(p,x) reactions., Comment: 34 pages, submitted to NIM-B

This study presents development of a test method for characterization of interlayer, mode-I fracture toughness of fused filament fabrication (FFF) materials using a modified double cantilever beam (DCB) test. This test consists of DCB specimen fabricated from using unidirectional FFF layers, an 8 μm Kapton starter crack inserted in the midplane during the printing process, and reinforcing glass/epoxy doublers to prevent DCB arm failure during loading. DCB specimens are manufactured with a commercially available 3D printer using unreinforced Acrylonitrile Butadiene Styrene (ABS) and chopped carbon-fiber-reinforced ABS (CF-ABS) filaments. To examine the effect of the FFF printing process on fracture toughness, additional ABS and CF-ABS specimens are hot-press molded using the filament material, and tested with the single end notch bend (SENB) specimen configuration. The fracture toughness data from DCB and SENB tests reveal that the FFF process significantly lowers the mode-I fracture toughness of ABS and CF-ABS. For both materials, in situ thermal imaging and post-mortem fractography shows, respectively, rapid cool-down of the rasters during filament deposition and presence of voids between adjacent raster roads; both of which serve to reduce fracture toughness. For CF-ABS specimens, fracture toughness is further reduced by inclusion of poorly wetted chopped carbon fibers. Although this study did not attempt to optimize the fracture performance of FFF specimens, the results demonstrate that the proposed methodology is suitable for design and optimization of FFF processes for improved interlayer fracture performance.

A continuous and uniform AZ31 magnesium alloy coating was deposited by magnetron sputtering to protect flexible polyimide substrate (Kapton HN) from atomic oxygen (AO) erosion-corrosion in low earth orbit. The AO erosion yield of the coated Kapton was determined to be 8.87 × 10−26 cm3 atom−1 after exposure to AO fluence of 1.47 × 1021 atoms cm−2, about 34 times lower than that of blank Kapton. XPS analysis results showed that an oxide layer of MgO formed on the surface of the coating after AO exposure, which is the main reason for the enhanced AO erosion-corrosion resistance of the AZ31 Mg-alloy coating.

Conducting polymer PEDOT:PSS [Poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate)], owing to its high electrical conductivity, enviornmental stability and low cost, is presently getting most attention for various device applications including thermoelectric, organic light emitting diodes and photovoltaics. We have investigated the irradiation effect of high energy electron beam on the electrical transport properties of PEDOT:PSS films to manifest the scope of this polymer in high radiation field and its suitability for radiation dosimeter applications. PEDOT:PSS films were deposited on flexible polyimide (Kapton) sheets using drop-cast method and irradiated up to 75 kGy dose with 1 MeV electron beam. The electrical conductivity of as deposited polymer film was ∼3.2 S/cm which consistently falls to ∼0.76 S/cm on irradiation dose of 75 kGy. Detailed characterization of the samples using x-ray photoelectron spectroscopy, contact angle measurement and solubility test conclusively suggested that the lowering of electrical conductivity in irradiated sample is attributed to the crosslinking of PEDOT chains and dissociation of PSS.

The effect on aircraft materials in the near space environment is a key part of air-and-space integration research. Ozone and aerodynamic fluids are important organizational factors in the near space environment and both have significant influences on the performance of aircraft materials. In the present paper a simulated ozone environment was used to test polyimide material that was rotated at the approximate velocity of 150–250 m/s to form an aerodynamic fluid field. The goal was to evaluate the performance evolution of materials under a comprehensive environment of ozone molecular corrosion and aerodynamic fluids. The research results show that corrosion and sputtering by ozone molecules results in Kapton films exhibiting a rugged “carpet-like” morphology exhibits an increase in surface roughness. The morphology after ozone exposure led to higher surface roughness and an increase in surface optical diffuse reflection, which is expressed by the lower optical transmittance and the gradual transition from light orange to brown. The mass loss test, XPS, and FTIR analysis show that the molecular chains on the surface of the Kapton film are destroyed resulting in C C bond breaking to form small volatile molecules such as CO2 or CO, which are responsible for a linear increase in mass loss per unit area. The C N and C O structures exhibit weakening tendency under ozone exposure. The present paper explores the evaluation method for Kapton’s adaptability under the ozone exposure test in the near space environment, and elucidates the corrosion mechanism and damage mode of the polyimide material under the combined action of ozone corrosion and the aerodynamic fluid. This work provides a methodology for studying materials in the near-space environment.

Thin 33S samples for the study of the 33S(n, α)30Si cross-section at the n_TOF facility at CERN were made by thermal evaporation of 33S powder onto a dedicated substrate made of kapton covered with thin layers of copper, chromium and titanium. This method has provided for the first time bare sulfur samples a few centimeters in diameter. The samples have shown an excellent adherence with no mass loss after few years and no sublimation in vacuum at room temperature. The determination of the mass thickness of 33S has been performed by means of Rutherford backscattering spectrometry. The samples have been successfully tested under neutron irradiation.

International audience; This paper is dedicated to the characterisation of charging behaviour of space used polymers in space electron environment. Spacecrafts are indeed submitted in Medium Earth Orbit (MEO) to severe fluxes of electrons with energies ranging from a few keV to several MeV. For qualification of materials used on satellites and the pre-diction of their electrostatic behaviour in space environment, it is therefore important to tests these materials in representative environment. These experiments have been carried out at ONERA, The French Aerospace Lab (Toulouse, France) in the SIRENE facility. Different polymers (PEEK, ETFE, Kapton®, polyurethane and silicone varnish, polyurethane based paint) have been characterised to extract the main electric parameter that steer their charging behaviour in space environment: the radiation induced conductivity (RIC). These materials have then been tested in representative environment so as to study the evolution of their conductivity and charging behaviour as a function of the received radiation dose (for low and high dose levels). From these experiments, it was possible to extract the physical parameters that steer RIC and assess numerically their charging levels in specific MEO environment.

The effect that filler size and content exerts on the out-of-plane effective thermal conductivities (TCs) of hexagonal boron nitride (hBN) and Kapton-type polyimide (PI) (hBN/PI) composite sheets was investigated in an effort to enhance the TCs of Kapton-type PI sheets. A TC-measurement apparatus that was devised based on the steady-state method was adopted. The apparatus was constructed in-house, and its validity was established. In this study, the effective TCs of composite sheets were increased with increases in the hBN size and volume fraction. The enhancement behaviors of the effective TCs obtained in the present work reasonably approximated the data in the literature regardless of the differences in either the preparation method of the composite or the monomer species of the PI. The Hamilton and Crosser model could reproduce the experimentally enhanced levels of effective TCs for all hBN/PI composites via adjustments to the configuration factors for hBN.

In this work, life cycle and thermomechanical behaviour for quaternary CuAlNiMn alloy, developed through thermal evaporation technique on flexible Kapton polyimide substrate were investigated. Scanning electron microscopic images displayed grains less than 150 nm without any porosity and crack. The thickness of the film was found to be around 6.6 μm, and the XRD profile revealed the presence of β′ (128) martensite peak. The austenite transformation temperature was As: 221 °C and Af: 226 °C as obtained from differential scanning calorimetry plots. Further, thermal images were recorded to analyse the heat transfer profile of the film during actuation at various points on the bimorph. The thermomechanical behaviour was studied by actuating the composite film through Joule heating under different loads of 30 mg, 45 mg and 60 mg. Parameters such as voltage and frequency were varied to analyse the actuation properties. The composite bimorph required less than 2 V to displace 4 mm under 60 mg load. The life of eight samples was recorded for more than 20,000 cycles, and the reliability of the film was investigated. The bimorph was further actuated by batteries to replicate the actuation and their suitability towards developing flappers for aerial robots. Keywords: CuAlNiMn, Thermomechanical behaviour, Life cycle, Actuation, Flapper

Acquiring good adhesion of ITO thin films on polymer substrate is a major concern, especially for space related applications. Delamination of ITO coating on these polymers can seriously damage the spacecraft. This paper presents the development of highly transparent and conducting ITO thin films on as-received and surface treated fluorinated ethylene propylene (FEP) and Kapton® substrates by reactive direct current magnetron sputtering. Stability of the ITO coating on FEP and Kapton® substrates was studied in simulated space environments. Environmental tests such as: relative humidity, thermal cycling and thermo vacuum were performed. Thermo-optical properties and sheet resistance of ITO coated FEP and Kapton® substrates were studied before and after environmental tests. Optimized ITO coating with thickness of ~ 15 nm on FEP and Kapton® substrates showed sheet resistance in the range of 2–4 kΩ/sq. with high average transmittance and high IR emittance. Adhesion of ITO coating on FEP substrate was improved by Ar plasma etching. X-ray photoelectron spectroscopy and field emission scanning electron microscopic studies of etched FEP substrate showed defluorination and high roughness of the etched surface which helped for better adhesion of ITO coating. We demonstrated that ITO coated plasma etched FEP substrate showed no change in the sheet resistance and thermo-optical properties. Moreover, ITO coated etched FEP substrate showed good environmental stability than ITO coated untreated FEP substrates.

High-efficiency heat-dissipation materials are in urgent need in microelectronics industry in 5G era. However, large-scale, low-cost, and high-efficiency preparation technologies still have great challenges. Here, ultrahigh thermal and electric conductive graphite films prepared by graphite-phase carbon nitride (g-C3N4) catalyzed graphitization of polyimide film (PI) were reported for the first time. The graphite film obtained from 0.25 wt% g-C3N4 catalyzed polyimide graphitization (G0.25) has homogeneous and perfect graphene structure and state-of-the-art properties. The d-spacing of the graphite layers is about 0.335 nm, which is similar to the ideal layer thickness of graphene (0.334 nm). The thermal conductivity is 1781 W·m−1·K−1 and the conductivity is 1.63 × 106 S·m−1, which is 1.49 and 2.18 times of graphite film from pure PI film, 1.94 and 2.34 times of graphite film from commercialized Kapton film (I-film), respectively. The thermal conductivity of G0.25 film is 4.52 times of Cu and 7.46 times of Al. More importantly, the addition of g-C3N4 can reduce the graphitization temperature from 2800 to 2500 ℃, which can reduce the energy consumption by 20.5% in the whole polyimide graphitization process. The developed preparation technology has important guiding significance and very attractive industrial application value for the preparation of large-scale, low cost and high-quality heat dissipation materials.

In this paper, a compressed antimony selenoiodide (SbSeI)-based hybrid piezo/triboelectric nanogenerator for mechanical energy harvesting is presented for the first time. Sonochemically-fabricated SbSeI nanowires were compressed under high pressure (120 MPa) to form a pellet for use as an experimental electrode. Kapton film was utilized as the other electrode. The basic parameters used for the triboelectric nanogenerator (i.e. surface roughness and dielectric permittivity) were thoroughly studied. The effects of distance between the Kapton and SbSeI electrodes, excitation signal shape, and applied force on the output voltage have been examined. The attempt to separate piezoelectric and triboelectric effects in the measured voltage response has been presented. The maximum peak-to-peak voltage value measured for a 50 g structure loaded was 2.71 V for rectangular signal excitation using an electromagnetic shaker with 80 Hz frequency. The prepared device generated a significantly higher voltage per surface area and force unit (15.8 V/(N·cm2)) in comparison with similar literature reported values for other piezo/triboelectric generators.

In present study, the free radical behavior and interface interactions were investigated on the SiO2 deposited polyimide using electron paramagnetic resonance spectroscopy and X-ray photoelectron spectroscopy, respectively. The results indicated that proton irradiation induced the formation of Si–NO and SiO2/C compounds. It is interested to note that the SiO2 at outmost surface and SiO2-PI interface evolved into Si–NO and SiO2/C, respectively. The reasons for the interaction are due to the irradiation induced degradation of amine groups and catalytical effect of free radicals aggregated in the interface. The irradiation induced segregation is the key factor to the distribution of Si-related compounds. The detailed mechanism was discussed in the paper.

To improve the ultrasonic imaging of composites, an all-printed nanocomposite sensor array (APNSA) is developed using a direct-write approach. Individual sensing elements of APNSA are inkjet printed by directly writing graphene/poly (amic acid) (PAA)-based nanocomposite ink on Kapton film substrates, with an ultra-thin thickness of ∼1 μm only. APNSA is morphologically tuned at a nano scale to be sensitive to acousto-ultrasonic waves of a broad band regime. Each sensing element features a homogenous and consolidated nanostructure , with which transient change of tunneling resistance between adjacent graphene nanoplatelets in the polyimide (PI) matrix can be triggered when the element is loaded with acousto-ultrasonic waves. The triggered quantum tunneling effect endows APNSA with capability to perceive dynamic strains in a broadband regime with high fidelity and accuracy. Compared with a conventional ultrasonic phased array which is of a low degree of compatibility with composites, APNSA can be fully integrated with the inspected composites. In conjunction with the use of the additively manufactured APNSA, ultrasonic imaging of composites can be implemented, spotlighting a nature of full integration of APNSA with composites for in situ structural health monitoring and anomaly detection, yet without degrading the original integrity of the composites.

Transparent and conducting thin films on flexible substrates have enormous applications in the areas of space, solar, displays, etc. We hereby report the sputter deposition of transparent and conducting ITO/Ag/ITO (IAI) thin films on commercially available flexible Kapton® substrate at a lower substrate temperature. IAI multilayer has been deposited by magnetron sputtering system using an alloy In:Sn (90%:10%) and Ag targets at room temperature without breaking the vacuum. The optimized IAI coating shows high transmittance (∼81.3% at λ = 650 nm) along with very low resistance (8.36 Ω/□). Optical haze value of IAI on Kapton was measured and found to be ϕ = T 10 R s . At λ = 650 nm ϕ = 15 × 10 - 3 Ω - 1 was observed. Our findings give worthful insight into the sputter deposition of transparent conducting IAI coating on flexible Kapton® substrate for flexible electronics applications.

Some highly stretchable kirigami metallic glass (MG) structures with ultra-small strain energy loss during cyclic loading are developed. Less than 3% of strain energy loss is achieved after 1000 loading/unloading cycles, which is much smaller than the Kapton or nanocomposites-based kirigami structures. By optimizing the kirigami pattern design and smoothing the kirigami cuts may further reduce the stress energy loss, and one kirigami MG structure even shows no obvious strain energy loss. They are potentially useful for developing reversible mechanical metamaterials/devices or substrates of functional optoelectronic devices.

Fasteners play a very vital role in all engineering applications mainly in automobile and aerospace industries. In these industries it is very important to reduce the weight of the components in order to increase the performance. Therefore, the role of polymer fasteners, which are lighter in weight, becomes significant. The polymers which are generally used to make fasteners are black glass reinforced nylon, Victrex peek polymer, highly kinked rigid-rod polyarylene, Nylon, PVC, Polypropylene, Phenolic, PTFE, G10, Kel-F, Delrin/Acetal, Neoprene, Mylar, Glass-filled nylon, Peek, CPVCABS, PVDF / Kynar, Isoplast, Nomex, Kapton, Polycarbonate, Polyethylene, Ultem. There is a need to understand the mechanics of mechanically fastened structures which will be very important in design specification of the polymer fasteners. The paper begins with the testing methodologies and modes to failure analysis, followed by prevention of failure and future trends.

In this article, we introduce an antenna printed on a flexible substrate. This prototype is intended for a flexible display device. The flexible screen has the advantage of being finer and more shock-resistant than the current slabs while allowing smart-phones to adapt to different uses due to its flexibility. The suggested antenna is a dipole with two symmetric frameworks printed on a Kapton polyimide substrate with a relative permittivity of 3.45 and a loss tangent of 0.002. The parametric study performed is based on the length and width of the proposed antenna; it shows that the proposed architecture is adapted to operate in the UHF band. The simulation and measurement results are in good similarity.

Recently, the demand for lightweight, flexible and wearable dye-sensitized solar cells has been increased rapidly. One driver for this is to meet the challenge of supplying power in e-textiles applications. Integrating this functionality in the textile will result in an improved feel of the fabric compared to the current approach of the integration of conventional plastic solar patches. A low temperature processed TiO2 paste was used in this work to develop a fabrication method based on screen printing and spray coating to obtain photovoltaic textiles. The fabrication method used is low temperature and is compatible with Kapton and standard woven 65/35 polyester cotton fabrics. Comparing to the latest literatures, [1–3] our results show an improved PV efficiency of 7.03% and 2.78% on Kapton and fabric respectively when using a platinum coated fluorine tin oxide (FTO) glass as the top electrode.

The influence of growth temperature (200–300 ℃) on the properties of gallium nitride (GaN) directly deposited on Kapton by plasma-enhanced atomic layer deposition (PEALD) has been systematically investigated. With increasing growth temperatures, the O content and surface roughness of the GaN thin films increase. Besides, the diffusion behavior of GaN in Kapton was found when the growth temperature exceeds 250 ℃. In this study, ultrathin ALD aluminum oxide (Al2O3) and aluminum nitride (AlN) films were proposed to see if they could alleviate and/or even suppress the negative effects of interface diffusion during high-temperature (≥250 ℃) GaN growth. It was found that oxygen impurities were significantly decreased within the as-deposited GaN. Furthermore, we observed a complete suppression of GaN diffusion into the Kapton throughout the entire growth process. Additionally, an introduction of either the Al2O3 or AlN before the GaN deposition could improve the surface morphology of the GaN deposited on Kapton.

SiOx/NiCr coatings with different SiOx thicknesses were deposited by the combination of ion implantation (IIP), filter cathode vacuum arc (FCVA), and electron beam (E-beam) evaporation methods to protect flexible Kapton from atomic oxygen (AO) attack. Due to the ion stitching effect and mechanical interlocking of implanted Ni+, the ductility and supporting effect of the fcc γ (Ni-Cr) alloy layer, and the low growth stress of the SiOx, the SiOx/NiCr coatings showed high adhesion and toughness. Exposure tests indicated that the AO erosion yield of the 1 μm-thick SiOx/NiCr-coated Kapton was 5.6 × 10−26 cm3 atom−1, which was attributed to the formation of a compact and continuous thin SiO2 layer. In addition, the inherent kinetic energy and oxidation performance dissipation of AO on the thick inner walls of cracks helped to reduce the cavity cross-sectional area and maximum width in the matrix.

A fully integrated dissolved oxygen (DO) sensor was fabricated using laser induced graphene (LIG). The LIG was patterned on polyimide (Kapton) film using CO2 laser followed by the electrodeposition of colloidal platinum to form the electroactive sensing area. The sensing area was insulated in an oxygen gas permeable membrane for selective detection of DO. The fabricated sensor demonstrated excellent catalytic activity towards the reduction of oxygen with a sensitivity of 246.66 µA/mMcm2 over a linear detection range of 30 µM to 400 µM. The sensor exhibited a limit of detection (LOD) of 2.4 µM DO and fast response time of 2 s. The LIG-based DO sensor also exhibited good selectivity and stability. The sensor was further evaluated in a cell culture system to monitor DO to maintain cell culture viability. The DO sensor showed good performance in detecting oxygen in fresh medium (82.2 µM), at 80% cell confluency (102.37 µM), and at 100% confluency (93.52 µM). The performance of the DO sensor offers great promise for detecting dissolve oxygen in cell culture systems for biomedical and environmental applications.

Although polyethylene (PE) is one of the most frequently used synthetic polymers in the plastics market, it is very difficult to imprint or bond PE with adhesives without pre-treatments based upon electrical, chemical and thermal processes. This is because a uniform adhesion property of PE cannot be expected without these processes. In this study, we suggest a simple, fast and cost-effective method to improve the adhesion properties of PE using a Kapton tape, which is a polyimide film generally used in flexible electronics. Specifically, by wrapping PE substrates applied with an adhesive using a Kapton tape and curing the sample using either a hot-press or a hot plate, the standard deviation of the shear strength decreased by 82.1% and 87.6%, respectively. To further improve the adhesion of PE substrates, we functionalized their surface using coupling agents, such as (3-glycidoxypropyl) methyldiethoxysilane and (3-aminopropyl) trimethoxysilane after an ultraviolet-ozone process. Using X-ray photoelectron spectroscopy and vacuum Fourier-transform infrared spectroscopy analysis, we proved that a significant improvement in the adhesion of PE occurred because of chemical crosslinking between either epoxy or amine groups functionalized on the PE substrates and epoxy-based adhesives comprising diglycidyl ether epoxy resin and triethylenetetramine hardener. This study is important, as it suggests a simple and very effective method to obtain highly reliable adhesion properties of PE using conventional adhesives.

We report fabrication of photoresponsive liquid-crystalline polymers reinforced with highly-oriented Kapton nanofibers with a supramolecular hydrogen bonding interface. To enhance the interfacial strength, hydroxyl groups are introduced into the side chain of azobenzene-containing liquid-crystalline polymers, forming hydrogen bonds with the Kapton nanofibers, directly imaged by nano-FTIR. Interestingly, the composite film exhibits the hierarchical structure of dragonfly wings, while demonstrating relatively high elastic modulus (1.64 GPa), reduced modulus (72.8 GPa), and nanohardness (4.5 GPa); 20–30 times higher than natural dragonfly wings. The enhanced mechanical performance and bilayer structure enables the composite film to exhibit rapid photoresponsive behaviors independent of the direction of illumination, due to an unconventional deformation mechanism arising from the interactions at the fiber-polymer interface. In addition, the flapping frequency and bending angle of the composite films can be continuously tuned for a single device (0.1–5 Hz, and 1.5–15.8°) by modifying the pulsed photoirradiation. The composite films are assembled into an artificial dragonfly device, and the light-driven flight aerodynamics are demonstrated in windy conditions. These not only provide a solution of micro-aircraft wings, but also offer a good bionic model for emulating dragonfly wings.

In this study, a fully printed carbon nanotube (CNT) based Thermoelectric Generator (TEG) is successfully fabricated, which exhibits excellent flexibility and remarkable power output, capable of high-temperature operation up to 350 °C. The TEG device can be easily manufactured through ink printing processes of low-cost aqueous single wall carbon nanotube-based (SWCNT) ink with a mask-assisted design. The optimal SWCNT-based thermoelectric (TE) films fabricated on high-temperature resistant polyimide (Kapton) substrate exhibit a remarkable power factor of 493 μW/mK2 at ΔΤ = 300 K, combined with excellent stability in air. The TEG device is capable to operate at temperatures up to 350 °C in ambient conditions (atmospheric pressure: 1 atm and relative humidity: 50 ± 5%). Together with exceptional stability and flexibility, the produced TEG exhibits thermoelectric performance values among the highest ever reported in the field of carbon-based and printed thermoelectric devices, with i.e. open-circuit voltage VOC = 1.11 V, short-circuit current ISC = 1.67 mA and internal resistance RTEG = 671 Ω at ΔT = 300 K, generating a maximum power output (Pmax) of 461 μW. The proposed TEG device architecture is easily scalable, enabling large-scale printing manufacturing opportunities towards highly efficient, high-operating temperature, printed and flexible carbon-based TEGs.

The electrophoretic deposition (EPD) of ZnO nanoparticles onto highly oriented pyrolytic graphite (HOPG) chips from a nonaqueous suspension is reported. Deposits are fast fired at 1200 °C in vacuum, and lifted off the substrate using Kapton tape. The SEM micrographs revealed exfoliated graphene multilayer flakes on the back surface of the ZnO layers. The I-V characteristics of the ZnO/HOPG junctions demonstrate the atmospheric sensitivity of the junction energy barrier. This is the first report of using HOPG chips as substrates for the EPD of metal oxides. Forming metal oxide/graphene junctions has explicit technical difficulties, and the presented method is anticipated to find niche applications in fabricating wide area metal oxide/graphene multilayer junction devices such as radiation detectors and supercapacitors.