This work was supported by National Natural Science Foundation of China (Grant Nos. 11402221 and 11502224), the State Key Laboratory of Intense Pulsed Radiation simulation and effect (SKLIPR1513) and the Hunan Provincial Key Research and Development Plan (No. 2016WK2014).

1. Fabricating Flexible PZT Thin Films
<ol>
	<li>Cut a 1 cm x 1 cm mica substrate from a mica sheet with scissors.</li>
	<li>Fix this 1 cm x 1 cm mica substrate on a desk using double-sided tape.</li>
	<li>Use tweezers to peel-off the mica layer-by-layer until the desired thickness (50 &#181;m), measured with a micrometer.</li>
	<li>Paste this freshly cleaved mica substrate on a 5&#39;&#39; substrate holder using a thin layer of silver paint and cure it at 120 &#176;C on a hot plate for 10 minutes to affix mica on substrate firmly.</li>
	<li>Put the PLD (Pulsed Laser Deposition) substrate holder into the PLD chamber.</li>
	<li>Select the repetition rate (e.g., 10 Hz) and laser energy (e.g., 300 mJ).</li>
	<li>Move the focusing lens to the set position.</li>
	<li>Open the shutter and deposit a 5 nm CoFe2O4 (CFO) [Laser energy: 300 mJ, Oxygen pressure: 50 mTorr, Sample temperature: 590 &#176;C, Deposition time: 5 min] thin film as a buffer layer by triggering the laser (Figure 1).</li>
	<li>Deposit a 20-80 nm SrRuO3 (SRO) [Laser energy: 300 mJ, Oxygen pressure: 100 mTorr, Sample temperature: 680 &#176;C, Deposition time: 10-30 min] on the CFO buffer layer as the bottom electrode for subsequent electrical performance tests by triggering the laser (Figure 1).</li>
	<li>Deposit a 150 nm PZT [Laser energy: 300 mJ, Oxygen pressure: 100 mTorr, Sample temperature: 650 &#176;C, Deposition time: 60 min] thin film on the top of SRO bottom electrode by triggering the laser (Figure 1).</li>
	<li>Vent the chamber using N2 and remove the PZT/mica sample (Figure 2) when the temperature reaches room temperature.</li>
	<li>Put the sample on a piece of glass.</li>
	<li>Put a predesigned mesh with 200 &#181;m diameter on top of the sample. Fix the mesh well and put mesh-sample into the sputtering chamber.</li>
	<li>Use DC sputtering (10 mA, 8 mbar, 6 min) to deposit Pt top electrodes on the film. Remove the sample after the sputtering.</li>
	<li>Use a knife or 20% HF acid to remove a 1 mm x 1 mm PZT section. This is to uncover the bottom SRO electrode and form many small flexible ferroelectric capacitors. 
	NOTE: Grow SRO as the bottom electrode, and then deposit Pt on top of the electrodes on the films by DC sputtering to form many small capacitors to measure the electronic properties of the PZT thin film, which is shown in Figure 3.</li>
	<li>Paint a coat of conductive silver on the exposed SRO to increase the electrical conductivity of the bottom SRO electrode. Ensure that the conductive silver can contact the exposed SRO.</li>
</ol>
2. Ferroelectric Characterization
<ol>
	<li>Bending Test
	<ol>
		<li>On the backside of the flexible sample, glue a piece of paper with the same size as the sample for easy transfer of the sample from one stage to another.</li>
		<li>Place the PZT/mica on the test board of the ferroelectric test system and semiconductor device analyzer.</li>
		<li>Put one measurement probe of the ferroelectric test system and semiconductor device analyzer on the Pt top electrode and put the other measurement probe on the silver-SRO layer to get the polarization-electric field (P-E) hysteresis loops and capacitance-electric field (C-E) curves while the sample is unbent.
		<ol>
			<li>Measure the P-E hysteresis loops with the two probes at a 2 kHz frequency and at 4 V. Measure the C-E curves with the two probes at a 1 MHz frequency and at 4 V. Remove the unbent sample.</li>
		</ol>
		</li>
		<li>Secure the flexible PZT/mica thin film on the desired mold using double-sided tape. Take care to avoid the slipping/gliding of mica during the measurement.</li>
		<li>Mount it on the test board of the ferroelectric test system and semiconductor device analyzer.</li>
		<li>Put one probe on the Pt top electrode while the other probe touches the bottom SRO electrode through the silver coating similar to the configuration used earlier (step 2.1.3).</li>
		<li>Measure the P-E hysteresis loops and C-E curves under various tensile and compressive bending radii (Figure 4).
		<ol>
			<li>Measure the P-E hysteresis loops with the two probes at a 2 kHz frequency and at 4 V. Measure the C-E curves with the two probes at a 1 MHz frequency and at 4 V.</li>
		</ol>
		</li>
		<li>Remove the flexible PZT sample when the P-E and C-E measurements are completed.</li>
	</ol>
	</li>
	<li>Thermal Stability
	<ol>
		<li>Put the PZT/mica on the test board of the ferroelectric test system and semiconductor device analyzer.</li>
		<li>Put one measurement probe on the Pt top electrode and put the other measurement probe on the silver-SRO layer.</li>
		<li>Open the temperature control system to heat the sample.</li>
		<li>Conduct the P-E and C-E measurements at different temperatures (25 &#176;C, 50 &#176;C, 75 &#176;C, 100 &#176;C, 125 &#176;C, 150 &#176;C, 175 &#176;C).</li>
		<li>Turn off the heater assembly after the measurements are done.</li>
	</ol>
	</li>
	<li>Bending cyclability tests
	<ol>
		<li>Mount the flexible PZT/mica into the two grooves of this setup.</li>
		<li>Fix one end of the sample while it is bent from the other end with the aid of a motor.</li>
		<li>Use a ruler to measure the PZT/mica length along with the movement (bending) direction of the motor prior to the 8 mm bending process (Figure 5).</li>
		<li>Calculate the movement length C to bend the sample 5 mm according to the formula: C=L-2Rsin(L/2R), where L is the length of PZT/mica in unbent state, R is the bending radii, and C is the movement length of the motor.</li>
		<li>Set number of bending cycles (1000) in the computer (Figure 6).</li>
		<li>Click the Start button (Figure 6) to initiate the back and forth motor motion.</li>
		<li>Remove the sample and measure the P-E to check whether the ferroelectric properties are retained.</li>
	</ol>
	</li>
</ol>

<ol>
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The authors have no competing financial interests to disclose.

The key step in the fabrication of ferroelectric elements lies in the use of a clean and even/flat substrate surface. Though freshly cleaved mica surface is atomically smooth, it is necessary to pay attention to preventing surfaces from suffering visible splintering, split layers, cracks, inclusions, etc. After deposition of the PZT layer, the sample was cooled under a high oxygen pressure (200-500 Torr) to reduce the oxygen vacancies. Ex situ top platinum electrodes were deposited via a predefined mesh...

The successful fabrication of flexible nonvolatile memory elements (NVME) plays a key role in exploiting the full potential of flexible electronics. NVME shall feature light weight, low cost, low-power consumption, fast speed and high storage density capabilities besides data storage, information processing and communication. Perovskite Pb (Zr,Ti)O3 (PZT) acts as a popular system for such applications considering its large polarization, fast polarization switching, high Curie temperature, low coercive field and high piezoelectric coefficient. In ferroelectric nonvolatile memories, an external voltage pulse can switch the two remnant polarizations between two stable directions, represented by &#39;0&#39; and &#39;1&#39;. It is non-volatile, and the write/read process can be completed within nanoseconds. NVME based on organic1,2,3,4,5,6 and inorganic7,8,9,10,11,12,13,14,15 ferroelectric materials have been attempted on flexible substrates. However, such integration is limited by not only the substrates&#39; inability of high-temperature growth but also the degraded device performance, current leakage and electrical shorting due to their rougher surfaces. Despite promising results, alternate strategies like the thinning of substrate8 and the epitaxial layer transfer on a flexible substrate15 suffer restricted viability in view of the sophisticated multistep process, the unpredictability of transfer, and the limited applicability.
For the aforementioned reasons, it is critical to explore an appropriate substrate that is able to overcome limited thermal and operational stabilities of soft substrates to further advance flexible electronics. A natural muscovite mica (KAl2(AlSi3O10)(OH)2) substrate with unique features like atomically smooth surfaces, high thermal stability, chemical inertness, high transparency, mechanical flexibility, and compatibility with current fabrication methods can be used to effectively deal with these issues. More so, the two-dimensional layered structure of monoclinic mica supports van der Waals epitaxy, which mitigates lattice and thermal matching conditions, thereby significantly suppressing the substrate clamping effect. These advantages have been exploited in the direct growth of functional oxides16,17,18,19,20,21,22,23 on muscovite recently, in view of flexible device applications.
Herein, we describe a protocol to directly grow epitaxial yet flexible lead zirconium titanate (PZT) thin films on muscovite mica. This is achieved through a pulsed laser deposition process relying on the versatile properties of mica, resulting in van der Waals heteroepitaxy. Such fabricated structures retain all the superior properties of epitaxial PZT on rigid single crystalline substrates and exhibits excellent thermal and mechanical stabilities. This simple and reliable approach provides a technological advantage over multistep-transfer and substrate thinning strategies and facilitates the development of much-awaited flexible yet single-crystalline non-volatile memory elements prerequisite for next-generation smart devices with high performance.

<table border="0" cellpadding="0" cellspacing="0" width="1114">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Equipment</td>
			<td style="width:387px;"></td>
			<td style="width:344px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">hot plate</td>
			<td style="width:387px;">Polish</td>
			<td style="width:344px;">P-20</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">PLD system</td>
			<td>PVD products</td>
			<td>PLD 5000</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Ferroelectric test system&#160;</td>
			<td>Radiant Technologies Precisions workstations&#160;</td>
			<td>RT66A</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Semiconductor device analyzer&#160;</td>
			<td>Agilent&#160;</td>
			<td>B1500A</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Bending molds</td>
			<td>home-made</td>
			<td></td>
			<td>Machined teflon material</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Bending stage</td>
			<td>home-built</td>
			<td></td>
			<td>Labview interfaced setup which provides a prescise displacemnt as small as 1 micrometer</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Sputtering system</td>
			<td>Beijing&#160;Elaborate</td>
			<td>ETD-3000</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Materials</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">mica(001) sheets</td>
			<td>Nilaco corporation&#160;</td>
			<td>990066</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">conductive silver paint</td>
			<td>Ted Pella, INC</td>
			<td>No.16033</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CoFe2O4 target</td>
			<td>Kurt J.Lesker</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">SrRuO3 target</td>
			<td>Kurt J.Lesker</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">PbZr0.2Ti0.8O3 target</td>
			<td>Kurt J.Lesker</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Pt target</td>
			<td>Hefei Ke jing</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a fabrication and measurement method for a flexible ferroelectric element based on van der waals heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

The epitaxial PZT/SRO/CFO/mica thin films were deposited with the pulsed laser deposition technique as outlined in Step 1. Figure 1 shows the growth scheme and Figure 2 shows an actual flexible NVM element based on the PZT.

Mechanical stability is a crucial aspect of flexible device application. The macroscopic ferroelectric performance of the heterostructure ag...

Watch this Scientific Journal Video about A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy at JoVE.com

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

a-fabrication-measurement-method-for-flexible-ferroelectric-element

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8.1K Views.  Xiangtan University. In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

Video: A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve the solar conversion efficiency of a concentrated photovoltaic system. The proposed system will also lower the solar cell cost in the concentrated photovoltaic system by replacing the expensive tandem solar cells with the cost-effective single junction solar cells. The structures and the parameters of high contrast gratings for the dispersive elements were numerically optimized. The large-area fabrication of high contrast gratings was experimentally demonstrated using nanoimprint lithography and dry etching. The quality of grating material and the performance of the fabricated device were both experimentally characterized. By analyzing the measurement results, the possible side effects from the fabrication processes are discussed and several methods that have the potential to improve the fabrication processes are proposed, which can help to increase the optical efficiency of the fabricated devices.

The fabrication of high contrast gratings as the parallel spectrum splitting dispersive element in a concentrated photovoltaic system is demonstrated. Fabrication processes including nanoimprint lithography, TiO2 sputtering and reactive ion etching are described. Reflectance measurement results are used to characterize the optical performance.

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve ...

Fabrication Process of Silicone-based Dielectric Elastomer Actuators

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an elastomeric dielectric membrane sandwiched between two compliant electrodes. The large actuation strains of these transducers when used as actuators (over 300% area strain) and their soft and compliant nature has been exploited for a wide range of applications, including electrically tunable optics, haptic feedback devices, wave-energy harvesting, deformable cell-culture devices, compliant grippers, and propulsion of a bio-inspired fish-like airship. In most cases, DETs are made with a commercial proprietary acrylic elastomer and with hand-applied electrodes of carbon powder or carbon grease. This combination leads to non-reproducible and slow actuators exhibiting viscoelastic creep and a short lifetime. We present here a complete process flow for the reproducible fabrication of DETs based on thin elastomeric silicone films, including casting of thin silicone membranes, membrane release and prestretching, patterning of robust compliant electrodes, assembly and testing. The membranes are cast on flexible polyethylene terephthalate (PET) substrates coated with a water-soluble sacrificial layer for ease of release. The electrodes consist of carbon black particles dispersed into a silicone matrix and patterned using a stamping technique, which leads to precisely-defined compliant electrodes that present a high adhesion to the dielectric membrane on which they are applied.

This manuscript shows the fabrication process for the manufacture of dielectric elastomer soft actuators based on silicone membranes. The three key stages of production are presented in detail: blade casting of thin silicone membranes; pad printing of compliant electrodes; and the assembly of all the components.

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

A Fabrication Method for Highly Stretchable Conductors with Silver Nanowires

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of stretchable electronic devices is the preparation of stretchable conductors with great mechanical stability. In this study, we developed a simple fabrication method to chemically solder the contact points between silver nanowire (AgNW) networks. AgNW nanomesh was first deposited on a glass slide via spray coating method. A reactive ink composed of silver nanoparticle (AgNPs) precursors was applied over the spray coated AgNW thin films. After heating for 40 min, AgNPs were preferentially generated over the nanowire junctions to solder the AgNW nanomesh, and reinforced the conducting network. The chemically modified AgNW thin film was then transferred to polyurethane (PU) substrates by casting method. The soldered AgNW thin films on PU exhibited no obvious change in electrical conductivity under stretching or rolling process with elongation strains up to 120%.

A simple synthesis method is used to chemically solder silver nanowire thin film to fabricate highly stretchable and conductive metal conductors.

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of ...

Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

Optimized sampling protocols and the development of new wipe materials can be facilitated by standardized measurements of collection efficiency from wipe-sampling. Our approach for sampling trace explosives uses an automated device to control speed, force, and distance during wipe-sampling followed by extraction of collected explosives.

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Fabricating van der Waals Heterostructures with Precise Rotational Alignment

In this work we describe a technique for creating new crystals (van der Waals heterostructures) by stacking distinct ultrathin layered 2D materials. We demonstrate not only lateral control but, importantly, also control over the angular alignment of adjacent layers. The core of the technique is represented by a home-built transfer setup which allows the user to control the position of the individual crystals involved in the transfer. This is achieved with sub-micrometer (translational) and sub-degree (angular) precision. Prior to stacking them together, the isolated crystals are individually manipulated by custom-designed moving stages that are controlled by a programmed software interface. Moreover, since the entire transfer setup is computer controlled, the user can remotely create precise heterostructures without coming into direct contact with the transfer setup, labeling this technique as &#8220;hands-free&#8221;. In addition to presenting the transfer set-up, we also describe two techniques for preparing the crystals that are subsequently stacked.

In this work we describe a technique that is used to create new crystals (van der Waals heterostructures) by stacking ultrathin layered 2D materials with precise control over position and relative orientation.

In this work we describe a technique for creating new crystals (van der Waals heterostructures) by stacking distinct ultrathin layered 2D materials. We ...

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...