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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 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.

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.

Electrostatic transducers promises a great potential in alternative to piezoelectric transducer based on certain advantages such as inherently wide bandwidth and good acoustic matching toair due to the membrane’s low acoustics impedance. There are two basic designs that are popular among electrostatic ultrasonic transducer developer –rigid backplate and micromachine backplate. This paper presents a methodology for improving the sensitivity of an air-coupled ultrasonic transducer by coupling the resonating thin plate, cavity and pipe in a single cell. The proposed device is termed Fluidically Amplified Ultrasonic Transducer (FLAUT) for an air-coupled application. Investigation of the concept of matched thin plate, cavity and pipe, of which the individual geometry is expected to mutually enhance one another. Analytical modelling is utilized to the matched thin plate, cavity and pipe. The analytical modelling identifies therequired geometry for the FLAUT based on the matched operating resonant frequency of 25 kHz. At the end of the paper the prototype of FLAUT is presented where the device was fabricated using additive manufacturing process (3-D printing) which consist of a 50 μm Kapton thin film over a micro stereolithography designed backplate. Here aluminum is coated as the electrode utilizing the thermal evaporation process for both the Kapton film and the backplate. A laser interferometer is utilized to measure FLAUT thin plate displacement which indicates the device is running at 25 kHz fundamental mode. A 30 dB difference is also observed between the deformation velocity of thecavity active region and its surrounding

In situ microplates are small in size, crystal cultivation and operation are difficult, and the efficiency of crystal screening is relatively low. To solve this problem, a novel combined crystallization plate was designed for high-throughput crystal cultivation and in situ data collection. A frame was used to hold 48 in situ microplates, and the in situ microplates were sealed on one side with an ultralow background-scattering Kapton film. An automatic liquid handler (Mosquito) was used to add a liquid drop to the in situ microplates in the frame, and CrystalClear HD tape was used to seal the frame. A sealed frame holding 48 microplates was developed as a novel combined crystallization plate and was used for crystal cultivation under different conditions and in situ data collection at the synchrotron beamline. Moreover, individual microplates can be separated from the combined crystal plate and then fixed on a magnetic base or loaded onto a UniPuck for in situ data collection. Automatic grid scanning was used to locate crystals. The efficiency of the combined crystallization plate for crystal screening was verified. This method avoids the manual manipulation of crystals during crystal screening and diffraction data collection; therefore, the combined crystallization plate is suitable for large-scale screening of microcrystals.

In this work, we successfully used wet etching to remove the Si substrate and transferred AlGaN/GaN high-electron mobility transistor (HEMT) film with a gate length of ${2}~\mu \text{m}$ to the flexible Kapton tape. The transferred area of AlGaN/GaN epitaxial thin film reached $1.2\times1.2$ cm2. The flexible HEMTs still exhibit excellent electrical characteristics with the maximum drain current density ( ${J}_{\text {DS,max}}$ ) of 290 mA/mm and the maximum transconductance ( ${g}_{\text {m,max}}$ ) of 108 mS/mm. Furthermore, we analyzed the physical mechanisms when devices were under bending. Under bending, the tensile strain enhances the piezoelectric field within the AlGaN layer, consequently increasing the 2-D electron density. In the condition that flexible HEMTs are bent with a curvature radius of 0.3 cm, ${J}_{\text {DS,max}}$ still reaches 346 mA/mm and ${g}_{\text {m,max}}$ achieves 125 mS/mm. Besides, the main reason for the decrease in dc characteristics is verified by self-heating. As for the RF characteristics, the Si substrate removal can effectively decrease the output parasitic capacitances. Although ${g}_{\text {m,max}}$ becomes half after the transfer processes, the cutoff frequency and the maximum oscillation frequency of flexible HEMTs still reaches 3.8 and 6.5 GHz, respectively.

This paper studies the performance of a resonant capacitive wireless power transfer (C-WPT) link for biomedical implants in the presence of non-idealities. The study emphasizes on finding an accurate electrical model of a practical C-WPT link, which can be used to investigate the performance of the link under different practical/non-ideal scenarios. A sound knowledge about these non-idealities is crucial for device optimization. For the first time, a circuit model has been presented and analyzed, which is applicable to a practical C-WPT link undergoing plate mismatch, flexion, tissue contraction, and stretching. Our model considers the finite conductivity of the body tissue and fringe fields formed by capacitor plates. Analytical and HFSSTM simulation results have been presented for different non-idealities, and are in good agreement. Additionally, we show a procedure to interpolate non-ideal case results. The study shows that plate misalignment (causing reduction in parallel plate overlap area) and skin tissue contraction (while muscle grows) are the most detrimental individual factors to the link performance. We recorded ∼32% and ∼14% power transfer efficiency decrease due to these two worst-case scenarios, respectively for a C-WPT link comprising of two pairs of 400 mm2 parallel plates (12 cm edge-to-edge separation) coated with 63.5 µm thick Kapton layer and aligned around a 3 mm tissue at 20 MHz.

This article intends to explore the optimal electrical characteristics of different winding processes for future high-field accelerator magnet insert. In the study, five double-pancake (DPC) racetrack ReBCO coils were wound by dry winding with no insulation (NI) process, dry winding with Kapton insulation (KI) process, wet winding with KI process, wet winding with NI process, and dry winding cowound with stainless steel tape process, respectively. The five DPC racetrack coils were fabricated and tested at 77 K in the Institute of High Energy Physics, Chinese Academy of Sciences. The article mainly presented the two winding processes, dry winding with NI and cowind with 304 stainless steel tape insulation since their special self-protect character during quench and delay effects during excitation and demagnetization. Through the experiments, we studied the characteristics of different winding processes and quench protection methods, which are important for the future application of High-temperature superconducting (HTS) insert coils.

Design and rapid prototyping of a tunable and compact microstrip antenna for industrial, scientific and medical (ISM) band applications is presented in this paper. Laser machining is introduced as a fast and accurate method for the antenna fabrication. The antenna, with an overall dimension of $65\times 46\times0.127$ mm, was fabricated by sandwiching a flexible Kapton polyimide substrate, with a dielectric constant of 3.5, between two flexible copper tapes, as the radiating patch and ground plane, respectively. The radiating patch was patterned in a meander configuration, with three slots, demonstrating the capability to reduce the resonant frequency of the microstrip antenna from 2.4 GHz to 900 MHz, without increasing the overall size of the antenna (87% compact). The effect of mechanical stress on the antenna performance was investigated by performing bend and stretch tests. The antenna was subjected to compressive bend with a minimum radius of curvature of 86 mm and 150 mm along the x-axis and y-axis which resulted in a maximum increase of resonant frequency by 3.1% and 1.3%, respectively. Similarly, the antenna was subjected to tensile bend with a minimum radius of curvature of 79 mm and 162 mm along the x-axis and y-axis which resulted in a maximum decrease of the resonant frequency by 4.2% and 0.3%, respectively. An overall 0.9% decrease in the resonant frequency was measured for an applied strain of 0.09% during stretching the antenna along the y-axis.

Metal–organic frameworks (MOFs) offer unique advantages including high surface area, porosity, size flexibility, and easy modification. MOFs can be chemically modified without changing the topology. The appealing properties of MOFs led to their utilization for the fabrication of triboelectric nanogenerators (TENGs) and the expansion of the triboelectric series with multifunctional materials. Here, a mixed linker MOF ZIF-62 of the zeolitic imidazolate framework (ZIF) subfamily for TENG is reported. The structural and morphological analysis confirms the successful formation of ZIF-62. The Kelvin probe force microscopy (KPFM) and surface potential measurement reveal the positive potential on ZIF-62. Teflon, Kapton, and ethyl cellulose (EC) are used as the opposite triboelectric layers to ZIF-62. The ZIF-62 TENG follows an output trend of TENG Teflon > TENG Kapton > TENG EC. The ZIF-62/Teflon TENG generated an output voltage, current, and charge of 62 V, 1.4 μA, and 16 nC, respectively. The fabricated device is demonstrated for fitness tracking and energy harvesting during numerous gym exercises such as hand curl, lateral raise, shoulder press, and squats. Finally, numerous low-power electronics is successfully powered with the output of ZIF-62 TENG via a charged capacitor.

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.

In this work, a simple procedure for the preparation of an inkjet printed disposable graphene electrode is reported. Commercial graphene ink was printed on a kapton substrate and the resulting electrode was 30 min treated by oxygen plasma, then modified by a bismuth salt. The as prepared electrode was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), laser scanning microscopy (LSM) and scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDX). The sensing properties of the characterized electrodes were then investigated using cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS). After-wards, these electrodes were exploited in a comparative way for the electroa-nalysis of Cadmium(II) and Lead(II) ions. An increase in the electrode sensi-tivity due to its modification and to the presence of bismuth was observed. Some preliminary experiments based on stripping square wave voltammetry highlighted the interest of using the proposed disposable inkjet printed elec-trodes for the electrochemical detection of heavy metals in tap water.

Piezoelectric PVDF sensors offer a unique option for the measurement of cavitation aggressiveness represented by the magnitude of impacts due to cavitation bubble collapses near walls. The aggressiveness measurement requires specific sensor shape and area, whereas commercial PVDF sensors are fabricated in limited geometry and size ranges. The photolithography method offers a possibility of production of home-made PVDF sensors of arbitrary shape and size. The methodology of a unique application of the standard photolithography method, which is commonly used for the production of printed circuit boards, is described in this paper. It enables mass production of high quality sensors contrary to laboratory techniques. This paper deals with the fabrication and the calibration of a photolithographically home-made PVDF sensor for the cavitation impact load measurement. The calibration of sensors was carried out by the ball drop method. Sensors of different sizes were fabricated by the photolithography method from a multi-purpose, both side metallized PVDF sheet. Commercial PVDF sensors of the same size were calibrated, and the calibration results were compared with the home-made sensors. The effect of size and the effect of one added protective layer of Kapton tape on a sensor sensitivity were investigated. The theoretical and numerical analysis was conducted to explain some issues during the ball impact.

In this work, we present a novel force-sensing device with zinc oxide nanorods (ZnO NRs) integrated with a metal-oxide-semiconductor (MOS) capacitor and encapsulated with Kapton tape. The details of the fabrication process and working principle of the integrated ZnO NRs-MOS capacitor as a force sensor and nanogenerator have been discussed. The fabricated ZnO-MOS device is tested for both the open-circuit and resistor-connected mode. For an input force in the range of 1–32 N, the open-circuit output voltage of the device is measured to be in the range of 60–100 mV for different device configurations. In the resistor-connected mode, the maximum output power of 0.6 pW is obtained with a 1 MΩ external resistor and input force of 8 N. In addition, the influence of different seed layers (Ag and ZnO) and the patterning geometry of the ZnO nanorods on the output voltage of ZnO-MOS device have been investigated by experiments. An equivalent circuit model of the device has been developed to study the influence of the geometry of ZnO NRs and Kapton tape on the ZnO-MOS device voltage output. This study could be an example of integrating piezoelectric nanomaterials on traditional electronic devices and could inspire novel designs and fabrication methods for nanoscale self-powered force sensors and nanogenerators.

Free chlorine is commonly used for disinfecting water for various purposes including drinking water, recreational water etc. The free chlorine concentration should remain within a range of 0.5 -2 ppm for an effective disinfection specially for drinking water. Therefore, a low-cost sensor is required to measure free chlorine concentration at different position of the water distribution channels to ensure safe and healthy water for public. Here, we demonstrate a low cost, flexible and solid state chemiresistive sensor fabricated on a Kapton tape with Graphene like Carbon as the sensing film and xurographically patterned gold leaf as the contact electrode. The fabrication process is simple, quick and robust to manufacture reproducible electrodes. The chemiresistive sensor was able to measure free chlorine concentration from 0.05 -1.75 ppm.

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.

Flexible humidity sensors play important roles in wearable devices and consuming electronics which provide a convenient way between digital and physical worlds. This work presents an easy fabricated method for flexible humidity sensors all based on carbon material including electrodes and functional layers. The interdigital electrodes are made by direct laser writing on commercial Kapton tapes and the transferring to flexible Polydimethylsiloxane (PDMS) substrates. The humidity sensing material is reduced graphene oxide (rGO) in nanometer thickness by electrospray. The rGO flakes covered the micro-size laser induced graphite (LIG), forming rGO-graphite balls, dramatically increase surface areas to interact with water molecules. The results show high precision sensitivity and fast response time for adsorption (0.9 s) and desorption (4.5 s). This method provides a novel method for fabricating cost-effective flexible humidity sensors.

Time-resolved terahertz spectroscopy has become a common method both for fundamental and applied studies focused on improving the quality of human life. However, the issue of finding materials applicable in these systems is still relevant. One of the appropriate solution is 2D materials. Here, we demonstrate the transmission properties of unique graphene-based structures with iron trichloride FeCl3 dopant on glass, sapphire and Kapton polyimide film substrates that previously were not investigated in the framework of the above-described problems in near infrared and THz ranges. We also show properties of a thin tungsten disulfide WS2 film fabricated from liquid crystal solutions transferred to a polyimide and polyethylene terephthalate substrates. The introduction of impurities, the selection of structural dimensions and the use of an appropriate substrate for modified 2D layered materials allow to control the transmission of samples for both the terahertz and infrared ranges, which can be used for creation of effective modulators and components for THz spectroscopy systems. Electronic supplementary material The online version of this article (10.1186/s11671-019-3062-3) contains supplementary material, which is available to authorized users.

The results of the performance tests of a three-layer foil separator for a high-current electron gun of an ELA excimer laser are presented. The separator consisted of two layers of thin titanium foil with a polyimide film between them. Such a composition withstood 5630 electron beam pulses with duration of 80 ns and an energy density per pulse of about 9 J/cm2. In this case, the polyimide film (Dupont Kapton polyimide film) with a thickness of 38 μm was irradiated with a dose of 1 GGy. The initial and induced absorption of this film was measured in the range from 20 to 0.4 μm. The mechanical tensile strength of the irradiated film decreased by 17 times.

Nanoindentation coupled with Atomic Force Microscopy was used to study stiffness, hardness, and the reduced Young’s modulus of reduced graphene oxide. Oxygen reduction on the graphene oxide sample was performed via LightScribe DVD burner reduction, a cost-effective approach with potential for large scale graphene production. The reduction of oxygen in the graphene oxide sample was estimated to about 10 percent using FTIR spectroscopic analysis. Images of the various samples were captured after each reduction cycle using Atomic Force Microscopy. Elastic and spectroscopic analyses were performed on the samples after each oxygen reduction cycle in the LightScribe, thus allowing for a comparison of stiffness, hardness, and the reduced Young’s modulus based on the number of reduction cycles. The highest values obtained were after the fifth and final reduction cycle, yielding a stiffness of 22.4 N/m, a hardness of 0.55 GPa, and a reduced Young’s modulus of 1.62 GPa as compared to a stiffness of 22.8 N/m, a hardness of 0.58 GPa, and a reduced Young’s modulus of 1.84 GPa for a commercially purchased graphene film made by CVD. This data was then compared to the expected values of pristine single layer graphene. Furthermore, two RC circuits were built, one using a parallel plate capacitors made of light scribed graphene on a kapton substrate (LSGC) and a second one using a CVD deposited graphene on aluminum (CVDGC). Their RC time constants and surface charge densities were compared.

Graphene oxide (GO) films are deposited on flexible Kapton substrates and selectively modified to conductive reduced graphene oxide (rGO) electrodes using laser patterning. Based on this, we design, fabricate, and test a flexible sensor integrating laser-reduced GO with silver plasmonic nanostructures. The fabricated device results in dual transduction channels: for electrochemical and plasmonic nanostructure-based surface-enhanced Raman spectroscopy (SERS) detection. The spectroscopic analysis verifying the formation of rGO and the modification by silver nanostructures is performed by Raman, energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The morphological investigation is followed by optical and scanning electron microscopy imaging. In addition to pristine silver nanostructures, the Raman spectroscopy results show the formation of species such as Ag2O, Ag2CO3, and Ag2SOx. A dual-channel sensor device based on electrochemical and plasmonic detection is fabricated as a demonstration of our Ag-rGO flexible concept architecture. The dual-channel device performance is successfully demonstrated in the electrochemical and SERS detection of 4-nitrobenzenethiol (4-NBT) using the same device. Our results show that without Ag nanostructures the sensitivity in the electrochemical and optical channels is not sufficient to detect 4-NBT. The performance and stability of the silver modified device are also verified. This work demonstrates an inexpensive, highly efficient, and greener way that is compatible with solution-processing technology for the production of flexible GO-based electrochemical and SERS detection devices integrated with plasmonic nanostructures.

This paper presents an ultra-wideband graphene antenna with tapered coplanar-waveguide feed. The proposed antenna covers the 2.7-8.2 GHz bandwidth (2.6-10 GHz measured), with two main resonance frequencies at 3.1 and 5.5 gigahertz (3.1 and 5.8 measured). Simulations show a radiation pattern that looks quasi-omnidirectional with a maximum gain limited to 3.15 dBi and efficiency above 84.7%. In order to post-process the graphene ink and to provide flexibility, Kapton Polyimide is used as a substrate. The flexibility, as well as the lightweight and ease in the fabrication of accurate designs, turns this antenna into a suitable candidate for wearable and flexible wireless applications.

Elastomers and, in particular, polydimethylsiloxane (PDMS) are widely adopted as biocompatible mechanically compliant substrates for soft and flexible micro-nanosystems in medicine, biology, and engineering. However, several applications require such low thicknesses (e.g.

Energy harvesting systems for low-power devices are increasingly being a requirement within the context of the Internet of Things and, in particular, for self-powered sensors in remote or inaccessible locations. Triboelectric nanogenerators are a suitable approach for harvesting environmental mechanical energy otherwise wasted in nature. This work reports on the evaluation of the output power of different polymer and polymer composites, by using the triboelectric contact-separation systems (10 N of force followed by 5 cm of separation per cycle). Different materials were used as positive (Mica, polyamide (PA66) and styrene/ethylene-butadiene/styrene (SEBS)) and negative (polyvinylidene fluoride (PVDF), polyurethane (PU), polypropylene (PP) and Kapton) charge materials. The obtained output power ranges from 0.2 to 5.9 mW, depending on the pair of materials, for an active area of 46.4 cm2. The highest response was obtained for Mica with PVDF composites with 30 wt.% of barium titanate (BT) and PA66 with PU pairs. A simple application has been developed based on vertical contact-separation mode, able to power up light emission diodes (LEDs) with around 30 cycles to charge a capacitor. Further, the capacitor can be charged in one triboelectric cycle if an area of 0.14 m2 is used., This research was funded by Fundação para a Ciência e Tecnologia under framework of the Strategic Funding UID/FIS/04650/2020 and projects UIDB/05549/2020 and TSSiPRO-NORTE-01-0145-FEDER-000015. The authors also thank the F.C.T. for financial support under grants SFRH/BD/140242/2018 (T.R.M.), SFRH/BPD/98109/2013 (P.C.). Finally, the authors acknowledge funding by Spanish State Research Agency (A.E.I.) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively, are also acknowledged.

The ATLAS Phase-II Upgrade will replace the Inner detector with a new all-silicon Inner Tracker (ITk) to accommodate the radiation damage and track density expected at the High-Luminosity LHC (HL-LHC). The all-silicon ITk for the HL-LHC consists of a pixel detector with 5 barrel layers and multiple forward disks at a small radius, and a strip tracking detector at the outermost part with 4 barrel layers and 6-end-cap disks on each side. This contribution presents the design of the flexible circuit (bus tape) for the local support structures of the end-cap region of the strip detector, called petals. The bus tapes provide the electrical interface to common services for all the on-board subsystems including power, control and data interfaces. Connections to external services outside of the petals are carried out through the End-of-Structure (EoS) card using optical fibres and copper wires. The bus tapes are manufactured as a 2-layer printed circuit board using polyimide and adhesive Kapton films, with a total thickness of 185 $\mu$m and a total length of 60 cm. The layout design has been focused on achieving good signal and power integrity while keeping low mass and low thermal resistance. A total of 768 end-cap bus tapes will be produced between 2021 and 2022 for the assembly of 384 petals with 6,912 modules, where each end-cap disk will consist of 32 petals.

In this study, a conformal loop antenna at 400 MHz frequency was designed and implemented for capsule endoscopy applications. The performance of the designed antenna has been further tested for the digestive system organs through which the capsule will move. In order to realize the designed antenna, the capsule is pressed with a three-dimensional printer, and the loop antenna printed on the copper plate is wrapped conformally on the outer surface of the capsule with the kapton tape. The results obtained from the measurements carried out in the laboratory were consistent with the simulation results.

An in-situ technique is presented for measuring the individual contact resistance between the pins of an IC package and a flexible substrate used in hybrid electronic systems. As the substrate flexes, the forces that adhere the IC to the substrate change and cause increase to the series contact resistance; sometimes catastrophically. Tracking this resistance is seen to be fundamental to the success of electronic systems mounted on a flexible substrate subjected to various levels of bending throughout its life cycle. The measurement technique exploits the electrostatic discharge protection circuitry in an IC chip to create a circuit loop involving the contact resistance and the series incremental resistance of the ESD circuit via two IC pins, one being the GND or VDD pin. While the series contact resistance between the pins of the IC package and the board can be measured with a four-point Kelvin measurement, it is extremely difficult to perform with small surface-mount IC package devices. The experimental results pertaining to Kapton polyimide substrate subjected to a controlled bending process will be described. The method proposed here will determine the contact resistance with a relative accuracy error of less than 1%.

A continuously-tunable terahertz (THz) bandpass filter based on the resonant electromagnetic-wave transmission through a metal-hole array featuring a gradually changing period was developed and fabricated on a silicon substrate using optical lithography. A gradient geometry of the metal-hole array yields a wide tunability of the filter transmission, when operating with a focussed THz beam. The filter was studied numerically, using the finite element method, and experimentally, using the THz pulsed spectroscopy. We find that the central wavelength of the filter transmission band can be tuned in the wide range of λc = 400–800 μm with the relative bandwidth of Δλ/λc ≃ ~0.4. Finally, Kapton-based anti-reflection coating was applied to the filter flat side, in order to suppress an interference pattern in the filter transmission spectrum. We believe that the developed filter holds strong potential for multispectral THz imaging and sensing due to its conceptual simplicity and case of operation. Moreover, the presented filter concept can be translated to other spectral ranges, where appropriate technologies are available for the fabrication of gradient sub-wavelength metal-hole arrays.

Here in this research, room temperature ethanol and humidity sensors were prepared based on two dimensional (2D) hybrid nanostructures of tungsten di-sulfide (WS2) nanosheets and graphene oxide nanoribbons (GONRs) as GOWS. The characterization results based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (ESD), Raman spectroscopy and X-ray diffraction (XRD) analysis confirmed the hybrid formations. Ethanol sensing of drop-casted GOWS films on SiO2 substrate indicated increasing in gas response up to 5 and 55 times higher compared to pristine GONRs and WS2 films respectively. The sensing performance of GOWS hybrid nanostructures was investigated in different concentrations of WS2, and the highest response was about 126.5 at 1 ppm of ethanol in 40% relative humidity (R.H.) for WS2/GONRs molar ratio of 10. Flexibility of GOWS was studied on Kapton substrate with bending radius of 1 cm, and the gas response decreased less than 10% after 30th bending cycles. The high response and flexibility of the sensors inspired that GOWS are promising materials for fabrication of wearable gas sensing devices.

Sample handling and manipulation for cryoprotection currently remain critical factors in X-ray structural determination. While several microchips for macromolecular crystallization have been proposed during the last two decades to partially overcome crystal-manipulation issues, increased background noise originating from the scattering of chip-fabrication materials has so far limited the attainable resolution of diffraction data. Here, the conception and use of low-cost, X-ray-transparent microchips for in situ crystallization and direct data collection, and structure determination at atomic resolution close to 1.0 Å, is presented. The chips are fabricated by a combination of either OSTEMER and Kapton or OSTEMER and Mylar materials for the implementation of counter-diffusion crystallization experiments. Both materials produce a sufficiently low scattering background to permit atomic resolution diffraction data collection at room temperature and the generation of 3D structural models of the tested model proteins lysozyme, thaumatin and glucose isomerase. Although the high symmetry of the three model protein crystals produced almost complete data sets at high resolution, the potential of in-line data merging and scaling of the multiple crystals grown along the microfluidic channels is also presented and discussed., This study was supported by project BIO2016-74875-P (MINECO), Spain co-funded by the Fondo Europeo de Desarrollo Regional (FEDER funds), European Union.

We present a rheometer that combines the possibility to perform in situ X-ray experiments with a precise and locally controlled uniaxial extensional flow. It thus allows us to study the crystallization kinetics and morphology evolution combined with the rheological response to the applied flow field. A constant uniaxial deformation rate is ensured, thanks to a fast control scheme that drives the simultaneous movement of the top and bottom plates during a pulling experiment. A laser micrometer measures the time evolution of the smallest diameter, where the highest stress is concentrated. The rheometer has a copper temperature-controlled oven with the ability to reach 250 °C and a N2 connection to create an inert atmosphere during the experiments. The innovation of our rheometer is the fixed location of the midfilament position, which is possible because of the simultaneous controlled movement of the two end plates. The copper oven has been constructed with four ad hoc windows: two glass windows for laser access and two Kapton windows for X-ray access. The key feature is the ability to perfectly align the midfilament of the sample to the laser micrometer and to the incoming X-ray beam in a synchrotron radiation facility, making it possible to investigate the structure and morphologies developed during extensional flow. The rheological response measured with our rheometer for low-density polyethylene (LDPE) is in agreement with the linear viscoelastic envelope and with the results obtained from the existing extensional rheometers. To demonstrate the capability of the instrument, we have performed in situ-resolved X-ray experiments on LDPE samples exhibiting extensional flow-induced crystallization. ispartof: REVIEW OF SCIENTIFIC INSTRUMENTS vol:91 issue:7 ispartof: location:United States status: published

Aerosol jet printing has been emerging as an attractive circuit fabrication technique in flexible and wearable radio frequency (RF) electronics due to the capabilities it provides beyond conventional fabrication techniques. In this paper, the effect of AJP process parameters on the printability of transmission lines on Kapton and LCP was investigated in details. Better wettability for the used ink on LCP has contributed to better line definition. The effect of sintering temperature and laser sintering power on the conductivity of transmission lines on both substrates was also studied. Employing Laser sintering has increased the conductivity significantly: 30% versus 10% of the silver bulk conductivity. However, the adhesion of the laser sintered lines on Kapton was very weak where all the lines fell off the substrate. On the other hand, the adhesion of the laser sintered lines on LCP was very good and passed multiple times of the tape test.Mircostrip lines were designed and fabricated on both substrates. The insertion loss for lines on LCP is around 0.32 dB/mm while on the Kapton samples is around 0.38 dB/mm at 40 GHz.

Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. The selected materials and fabrication methods provided great control over the ink rheology and material deposition, which enabled stable and repeatable electrochemical response: bending tests revealed the electrochemical behavior of these sensors remained consistent over 1000 bend cycles. Due to the abundance of structural defects (e.g., edge defects) present in the exfoliated graphene platelets, cyclic voltammetry (CV) of the graphene electrodes showed good electron transfer (k = 1.125 × 10−2 cm s−1) with a detection limit (0.01 mM) for the ferric/ferrocyanide redox couple, [Fe(CN)6]−3/−4, which is comparable or superior to modified graphene or graphene oxide-based sensors. Additionally, the potentiometric response of the electrodes displayed good sensitivity over the pH range of 4–10. Moreover, a fully IJP three-electrode device (MLG, platinum, and Ag/AgCl) also showed quasi-reversibility compared to a single IJP MLG electrode device. These findings demonstrate significant promise for scalable fabrication of a flexible, low cost, and fully-IJP wearable sensor system needed for space, military, and commercial biosensing applications.

Large area graphene-poly (methyl methacrylate) (PMMA) closed cavity resonator has been fabricated. The resonator has been formed by transferring an ultra-large graphene-PMMA membrane over 3.5 mm diameter circular closed cavity with $220~\mu \text{m}$ depth. The graphene-PMMA membrane includes 6-layer graphene and 450 nm PMMA film. A modified graphene-PMMA dry transfer method has been developed in this work. Using the Kapton tape supporting frame, the graphene-PMMA membrane has been dry transferred onto the substrate with a small membrane’s static deformation of around 180 nm. The membrane’s static deformation aspect ratio (suspended membrane’s diameter over the membrane’s deformation) is around 19,500. The graphene-PMMA closed cavity resonator has been actuated mechanically, acoustically and electro-thermally. The dynamic behaviour of the membrane suspended over the closed cavity shows that the (1, 1) mode dominates the graphene-PMMA membrane’s resonance with a resonant frequency of around 10 kHz and suggests the device is under good gas encapsulation. Acoustic vibration amplitude sensitivity of graphene-PMMA membrane over the closed cavity is measured to be around $6~\mu \text{m}$ /Pa. The membrane’s dynamic behaviour, simulated under similar mechanical and electro-thermal actuation conditions, has been shown to be consistent with the trend of the device’s experimental results. The strain in the suspended graphene-PMMA membrane is estimated to be 0.04 ± 0.01 %.

In the last decade, wearable sensors have gained a key role on biomedical research field for reliable health state monitoring. A wide plethora of physics marker sensors is already commercially available, including activity tracker, heart rate devices, and fitness smartwatch. On the contrary, wearable and epidermal sensors for chemical biomarker monitoring in several biofluids are not ready yet. Herein, we report a wireless and flexible epidermal device for pH monitoring in sweat, fabricated by encompassing a screen-printed potentiometric sensor, an integrated circuit, and antenna embedded onto the same Kapton substrate. An iridium oxide film was electrodeposited onto the graphite working electrode providing the pH sensitive layer, while the integrated circuit board allows for data acquisition and storing. Furthermore, a radio frequency identification antenna surrounding the entire system enables data transmission to an external reader up to nearly 2 m in the most favourable case. The potentiometric sensor was firstly characterised by cyclic voltammetry experiments, then the iridium oxide electrodeposition procedure was optimised. Next, the sensor was tested toward pH detection in buffer solutions with a near-Nernstian response equal to −0.079 ± 0.002 V for unit of pH. Interference studies of common sweat ions, including Na+, K+ and Cl−, showed any influence on the pH sensor response. Finally, the integrated epidermal device was tested for real-time on-body pH sweat monitoring during a running activity. Data recorded for a running subject were wireless transmitted to an external receiver, showing a pH value close to 5.5, in agreement with value obtained by pH-meter reference measurement.

Plasma actuators have attracted interest for use as active flow control devices due to their many benefits; they have no moving parts and are lightweight, can be flush mounted, and require low power. In this study, the performance of plasma actuators are experimentally characterized with dielectric material, dielectric thickness, and operating frequency for surface and channel actuator geometries. The channel height, changing the effective dielectric constant, is also varied. Induced velocities were measured using a pitot tube and PIV, and power consumption levels were recorded. For the surface plasma actuator, PTFE and GRE dielectric materials show similar performance, with Kapton producing the highest induced velocity jet. Higher plasma ionization tends to occur with operating frequencies of 5 and 10 kHz, with a minimum at 7 kHz – possibly related to a change to streamer discharge from corona discharge. Power consumption was also higher at frequencies of 5 and 10 kHz. Thinner dielectric materials outperformed thicker ones for a given high voltage input. GRE, which has the highest dielectric constant of the tested materials, resulted in higher induced velocities than PTFE and Kapton for the same dielectric thickness. For the channel actuator, the smallest air gap corresponding to the lowest permittivity generated the highest peak induced velocity at 12 kHz. Different air gap heights do not seem to affect the induced velocities for frequencies above 14 kHz. A high gradient of velocity reduction with streamwise distance from the exposed electrode of the channel actuators was also observed.

We present a novel DIY fabrication workflow for prototyping highly flexible circuit boards using a laser cutter. As our circuits consist of Kapton and copper, they are highly conductive and thus support high-frequency signals, such as I2C. Key to our approach is a laser machine that supports both a CO2 laser as well as a fiber laser to precisely process respectively Kapton and copper. We also show how the laser cutter can cure soldering paste to realize VIAs (Vertical Interconnect Access) and solder components. In contrast, previous approaches for prototyping flexible PCBs through laser cutting only considered CO2 lasers which can not process metals. Therefore these approaches mainly used ink-based conductors that have a significantly higher electrical resistance than copper.

The production of electrodes and sensors using plastic substrates has increased substantially for the last decades. Although devices are fabricated using plastic substrates suitable for the purpose of each device, it is difficult to find a process that can be used commonly for most types of plastics. In this paper, two kinds of electrode fabrication process that can be applied to most plastic films using kapton double sided tape and gold leaf are proposed. One is for the plastic film with adhesive and the other is for the film without adhesive. First, the kapton double-sided tape was patterned using a CO 2 laser. After transfer double-sided tape to desired substrate, release paper was detached and gold leaf was attached on the exposed side of the tape. Then, the tape was appropriately removed according to the presence or absence of the adhesive. After that, the packaging was performed using an adhesive when the used film has adhesive, and otherwise, heat press was used for packaging. These processes have a variety of advantages such as inexpensive, fast-running and commonly applicable to many plastics. To prove its usability, impedance and minimum line width was measured.

International audience; The development of three-dimensional (3D) porous graphitic structures is of great interest for electrochemical sensing applications as they can support fast charge transfer and mass transport through their extended, large surface area networks. In this work, we present the facile fabrication of conductive and porous graphitic electrodes by direct laser writing techniques. Irradiation of commercial polyimide sheets (Kapton tape) was performed using a low-cost laser engraving machine with visible excitation wavelength (405 nm) at low power (500 mW), leading to formation of 3D laser-induced graphene (LIG) structures. Systematic correlation between applied laser dwell time per pixel ("dwell time") and morphological/structural properties of fabricated electrodes showed that conductive and highly 3D porous structures with spectral signatures of nanocrystalline graphitic carbon materials were obtained at laser dwell times between 20 and 110 ms/pix, with graphenelike carbon produced at 50 ms/pix dwell time, with comparable properties to LIG obtained with high cost CO 2 lasers. Electrochemical characterization with inner and outer sphere mediators showed fast electron transfer rates, comparable to previously reported 2D/3D graphene-based materials and other graphitic carbon electrodes. This work opens the way to the facile fabrication of low-cost, disposable electrochemical sensor platforms for decentralized assays.

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.

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.

We have fabricated a flexible thin-film transistor (TFT) with relevant high performance indices using polymer electrolyte as gate dielectric and amorphous indium–gallium–zinc–oxide (a-IGZO) (a-InGaZn2O5) as a channel on polyimide Kapton tape. Low temperature ( $\approx 100~^{\circ }\text{C}$ –120 °C) prepared a-IGZO, showed n-channel device characteristic, and operated in the enhancement mode with a high saturation mobility of 42 cm2/ $\text {V}\cdot \text {s}$ , good ON/OFF ratio of ~105, low threshold voltage of ~0.7 V, and low subthreshold swing of ~175mV/decade. The improvements of the performance indices arise due to influence high value of specific gate capacitance of polymer electrolyte. The gate bias stress test of the flexible TFT showed the stable electrical characteristics.

A simple and facile method for obtaining patterned graphene under ambient conditions on the surface of diverse materials ranging from renewable precursors such as food, cloth, paper, and cardboard to high-performance polymers like Kevlar or even on natural coal would be highly desirable. Here, we report a method of using multiple pulsed-laser scribing to convert a wide range of substrates into laser-induced graphene (LIG). With the increased versatility of the multiple lase process, highly conductive patterns can be achieved on the surface of a diverse number of substrates in ambient atmosphere. The use of a defocus method results in multiple lases in a single pass of the laser, further simplifying the procedure. This method can be implemented without increasing processing times when compared with laser induction of graphene on polyimide (Kapton) substrates as previously reported. In fact, any carbon precursor that can be converted into amorphous carbon can be converted into graphene using this multiple lase method. This may be a generally applicable technique for forming graphene on diverse substrates in applications such as flexible or even biodegradable and edible electronics.

Pressure sensors with high sensitivity, repeatable output, wide sensing range, suitable for mass production and which can be manufactured cost effectively are highly desirable for pressure sensing applications. Over the years Graphene and rGO (reduced graphene oxide) based strain gauges have typically been prepared on substrates such as silicon, polydimethylsiloxane, polyethylene terephthalate, kapton, and rubber. They have mainly been utilized in the wearable and temperate condition applications. In the proposed work we would like to present a stainless steel based pressure sensor using rigid centre diaphragm and a fixed guided beam along with rGO-filter paper based strain gauges (reduced graphene oxide on a cellulose filter paper). The resulting strain on the fixed guided beam due to the applied pressure is sensed by the rGO-filter paper based strain gauges and the output is measured as change in resistance. The analytical, numerical simulation and experimental studies of this sensor are discussed and the results obtained are in good agreement to each other. The performance of the sensor is evaluated experimentally and is compared against a standard strain gauge for a pressure range of 0 to 20 bar. The developed sensor exhibits a pressure sensitivity of 2.29 Ω/bar, with an enhanced gauge factor of 112 and the effect of temperature is nullified. The high sensitivity and a wide sensing range enable it for a broad variety of applications.

Additive Manufacturing (AM) processes enable the fabrication of miniaturized and flexible devices on complex geometries. This paper explores a hybrid additive manufacturing technology that integrates micro-extrusion and PICO-jetting methods. Conductive slurries and colloidal inks were optimized for their rheological properties to aid their precise deposition. A variety of conductive materials which include carbon, silver, nano-particle silver and nickel were deposited on both rigid (glass) and flexible (Kapton) substrates. The deposited traces were cured using two sintering mechanisms which include furnace heating and in situ laser irradiation. The effect of curing mechanism on the conductance of deposited traces was evaluated. The results indicated that traces could be cured successfully with the laser curing mechanism. Nickel and silver laser cured traces had lower resistivity than the furnace sintered traces. An increase in the laser power resulted in lower resistivity of the traces. The lowest resistivity was achieved at 40W laser power with a single laser pass. Scanning electron microscopy and energy dispersive spectroscopy were used to characterize the trace morphology and elemental compositions. Higher power laser curing resulted in better bonding of the particles. Laser cured samples had minimal oxidation to the cross-section region of the traces as compared to furnace cured samples. This research lays the foundation for the fabrication of electronic components for a high level of freeform 3D electronics using a hybrid additive manufacturing technology.

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.

In this paper, the effect of polarity on the volume conductivity of Kapton and polyethylene (PE), determined using the corona triode method, when the sample current depends linearly on grid potential, was studied. For the determination of volume conductivity, in addition to the analytical method, for the first time, a graphical method is presented as well. According to the experimental results, obtained by both methods, the volume conductivity values of negative corona charged samples were higher than those of the samples charged by positive corona. Considering the different nature of positive and negative coronas, these differences in results are to be expected and are in full accordance with the theoretical considerations as well. On the other hand, the good agreement between the analytical method results and those obtained by the graphical method, indicates high accuracy of the proposed analytical formula. Meanwhile, the satisfying accordance of experimental results with those found by the classical “static” and “dynamic” methods, confirms the accuracy of the corona method, for the determination of volume conductivity of polymers.

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.

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.