Lamination Method Research Articles

Novel shear thickening gel/high‐performance fiber reinforced flexible composites: Multi‐velocity impact and functional properties

AbstractShear thickening gel (STG) is a promising substrate used for flexible protective materials, which has superior dimensional stability without gel side leakage and delamination when sustaining long‐standing time. STG/high‐performance fiber flexible composites exhibit high‐energy absorption capacity for multi‐velocity impact. This article reveals the shear thickening mechanism of STG that lays a theoretical foundation for the performance analysis of STG composites. The preparation methods of STG/high‐performance fiber flexible composites, including impregnation, hand lay‐up, filling, and lamination methods, are compared. The energy absorption principle of STG/high‐performance fiber flexible composites on multi‐velocity impact and the destruction morphology was analyzed. The coupling effects and functional applications of STG functional composites with nanoparticles, magnetic particles, and conductive particles are summarized. It provides more suitable conditions for designing new multifunctional protective equipment and manufacturing advanced intelligent, protective devices.

Achieving Low‐Voltage Operation of Intrinsically‐Stretchable Organic Light‐Emitting Diodes

AbstractA minimum operating voltage of intrinsically‐stretchable organic light‐emitting diodes (ISOLEDs) is always required for practical applications. However, the lack of protocols for the lamination complicates the task of attaining a reliable ISOLED without inducing degradation. Here, a solvent‐vapor‐assisted lamination (SVAL) method to reinforce the cathode interface is presented; this process lowers the operation voltage and increases the stretchability of ISOLEDs. Achieving a uniform contact and strong adhesion at the interface is the key to attaining reliable lamination. A cold‐pressing (CP) treatment is applied first to reduce the surface roughness of silver nanowires before the surface embedding process. A subsequent solvent vapor treatment before the lamination partially solvated the surface of the active layer with an increase in the segmental motion of polymer chains, which substantially increases the interfacial adhesion after lamination. The combination of CP and SVAL treatments considerably reduces threshold voltage Vth (i.e., voltage at which current shows an abrupt increase for light‐emission) from 6.7 to 2.7 V. The ISOLED also exhibts excellent mechanical stretchability, with no significant change in luminance under 30% strain. This study can assist in the development of practical applications of intrinsically‐stretchable optoelectronic devices.

Enhanced electromagnetic shielding of lightweight copper-coated nonwoven laminate with carbon filament reinforcement

Textile-based electromagnetic interference (EMI) shielding materials with good flexibility and high EMI shielding effectiveness (SE) are highly desirable. Still, the poor mechanical properties of textile-based EMI shielding materials limit their application. The carbon filaments (CF) combine superior mechanical properties and conductivity. Therefore, we demonstrate the CF-reinforced material, which was laminated with two types of copper-coated nonwoven polyester (CuPET10 and CuPET20) for EMI shielding. Compared to the traditional lamination method, this process was more convenient by ironing with adhesive lining. The developed laminate (CuPET/CF) performs superior EMI shielding property with an average SE value of 88.6 dB in the frequency range of 30 MHz to 3 GHz. The mechanical properties were improved from 12.7 to 39.9 MPa and from 13.46 MPa to 35.78 MPa for CuPET10/CF and CuPET20/CF, respectively. The newly developed material also demonstrated exceptional lightweight, flexibility, and thermal resistance. The laminated CuPET/CF material provides enhanced mechanical properties and easy lamination capability, allowing it to shield surfaces of electromagnetic radiation-sensitive equipment while providing a certain degree of protection and extremely high EMI shielding efficiency.

An Ordinary State-Based Peridynamic Model of Unidirectional Carbon Fiber Reinforced Polymer Material in the Cutting Process

Due to the complexity of the composite structure, analyzing the material failure process of carbon fiber reinforced polymers (CFRP) is fairly difficult, particularly for the machining process. Peridynamic theory, a new branch of solid mechanics, is a useful tool for dealing with discontinuities. This study presents an ordinary state-based peridynamic (OSB-PD) model for unidirectional CFRP material in the cutting process. In this model, angle tolerance is used to overcome the fiber angle limitation in a classical OSB-PD laminate method, and the short-range force approach is utilized to simulate the contact of the cutting tool and workpiece. The effectiveness of the supplied models is validated by tension and cutting tests. Finally, it can be indicated that the OSB-PD model is capable of predicting machined surface damage and cutting force, based on the comparison of simulation and experimental data.

A new black to highly transmissive switching bilayer polymer composite films with electroactive pEA as a color buffer layer for improving electrochromic stability

AbstractTwo reported D‐A‐D monomers based on 3,4‐ethylenedioxythiophene (EDOT) were selected for electrochemical copolymerization to obtain copolymer film, named pRG. Then, a soluble polymer poly[3,4‐ethylenedioxythiophene‐alt‐3,4‐bis([2‐ethylhexyl]oxy)thiophene] (pEA) based on the EDOT derivative was screened out, which is complementary to the absorption trough of the pRG film in visible region and matched with its working potential. The bilayer composite film pRG/pEA was obtained by spinning pEA basement membrane on fluorine doped tin oxide (FTO) coated glass surface, and then in situ electrochemical polymerization of pRG film. Compared to the pRG monolayer film, the bilayer composite film shows a more saturated black color in the neutral state and significant improvement on cyclic stability (only decreased by 1.7% after 250 cycles, while pRG film decreased by 17.1%). The introduction of pEA buffer layer not only achieves the full spectral absorption of the composite film in the visible region, but also significantly improves the cyclic stability of the bilayer composite film. The assembled EC prototype device based on the pRG/pEA composite film exhibits a “black to high transmission” reversible switch. Finally, this method combining electrochemical copolymerization, spin‐coating, lamination and other methods provides a new research idea for designing and preparing black to transmissive electrochromic materials.

Designing polyimide/polyacrylonitrile/polyimide sandwich composite separator for rechargeable lithium-ion batteries

The thermal stability of lithium-ion battery separator is very desirable to satisfy the requirements of EVs. Polyacrylonitrile (PAN) fiber membranes with excellent ionic conductivity and polyimide (PI) with excellent mechanical properties and flame retardancy have been attracted much attention. In this study, a PI/PAN/PI sandwich separator with three-dimensional network and sponge-like structures is prepared via electrostatic spinning, non-solvent phase separation and pressed lamination method. Compared with the cells with the typical PP separators, original PAN and PI separators, the cells assembled with the PI/PAN/PI sandwich separators presented an optimum rating and cycling capability, higher discharge capacity and lower internal resistance. The maximum discharge capacity of PI/PAN/PI separator was obtained 151.56 mAh g−1 at 0.1C, and the capacity retention could be maintained 94.3 % at 1C after 100 cycles during the charge and discharge process. Besides, the PI/PAN/PI separator exhibits excellent mechanical properties (18.12 MPa) and flame retardant performance. These results indicate that this process of PI/PAN/PI sandwich separator can be an efficient and applicable approach for preparing high performance separators, which will lead to stable cyclability and superior C-rate capacity.

Mechanical characteristics of laminated film vibrator using an ultra-thin MEMS actuator

This paper describes fabrication of a laminated film vibrator that uses an ultra-thin micro-electric mechanical system (MEMS) and the effect of lamination on the actuator. The thickness of the ultra-thin MEMS actuator fabricated by ultra-thin MEMS technology was 7.26 µm, making it especially flexible. The vibrator was actuated by applying voltage on a lead zirconate titanate (PZT) thin film. Then, we applied a lamination method to package the actuator. However, the lamination structure influenced the mechanical characteristics of the vibrator. Therefore, we evaluated the effect of the lamination structure on the static and dynamic characteristics of the laminated film vibrator. Four types of laminated film vibrators with different layer structures were prepared, and their displacements and velocity were measured when DC and AC voltages were applied. The maximum displacement of the cantilevers constructed from the laminated film vibrator (PZT: 11 mm × 11 mm) was 113.3 µm at 40 V DC. This result is in good agreement with the calculated result. Furthermore, the dynamic characteristics from both the experimental and simulated results confirmed that the resonant frequency of the laminated film vibrator depends on the film structure. This means the dynamic characteristics can be adjusted to suit the application. Applications of this laminated film actuator include use as a flexible hybrid electronics haptic device for monitoring vital signs.

Rapid, inexpensive fabrication of electrophoretic microdevices for fluorescence detection.

The laser print, cut, and laminate (PCL) method for microfluidic device fabrication can be leveraged for rapid and inexpensive prototyping of electrophoretic microchips useful for optimizing separation conditions. The rapid prototyping capability allows the evaluation of fluidic architecture, applied fields, reagent concentrations, and sieving matrix, all within the context of using fluorescence‐compatible substrates. Cyclic olefin copolymer and toner‐coated polyethylene terephthalate (tPeT) were utilized with the PCL technique and bonding methods optimized to improve device durability during electrophoresis. A series of separation channel designs and centrifugation conditions that provided successful loading of sieving polymer in less than 3 min was described. Separation of a 400‐base DNA sizing ladder provided calculated base resolution between 3 and 4 bases, a greater than 18‐fold improvement over separations on similar substrates. Finally, the accuracy and precision capabilities of these devices were demonstrated by separating and sizing DNA fragments of 147 and 167 bases as 148.62 ± 2 and 166.48 ± 3 bases, respectively.

A Multilayer Transparent Bamboo with Good Optical Properties and UV Shielding Prepared by Different Lamination Methods

A Multilayer Transparent Bamboo with Good Optical Properties and UV Shielding Prepared by Different Lamination Methods

Expansion of food types via 3D food printing: artificial meat, super-care food, 4D food, and edible robots

In recent years, many companies and research institutes have been conducting research on food 3D printers. The most commonly known 3D printing method is the thermal melting and lamination method, fused deposition modeling (FDM), in which plastic materials are melted and then ejected from a nozzle. The plastic materials used in this method are thermoplastic resins such as ABS and PLA. In order to 3D print a variety of materials, various types of 3D printing methods have been developed, and it is currently already possible to 3D print materials including metal, wood, and gel. There is also a growing movement to apply this technology to the food industry to create food using 3D printers. There are a variety of food materials, such as chocolate, jelly, and dough, and accordingly, there are various types of 3D printing methods, such as the syringe method and the screw method. In this paper, we introduce various types of food 3D printers and their applications.

Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process

Vinyl ester (VE) resin has strong environmental tolerance and is the matrix commonly used in the composite materials of fiber-reinforced plastics (FRP). VE resin is often combined with glass fiber in different maritime structures, such as wind turbine blades, spinner cases, and nacelle cases. However, VE resin exhibits exothermic reactions and shrinkage during curing, which often generates residual strain in large structures and those with a high stacking number. This study explored the exothermic reaction and shrinkage of VE resin and glass fiber during the vacuum-assisted resin transfer molding process, as measured using a fiber Bragg grating sensor. The experiment results verified the relationship between the stacking number and residual strain shrinkage. In addition, the symmetric laminate method was used to prevent the bending–twisting coupling effect and subsequent warping deformation of the FRP laminated plate during curing. The experiment results also verified that the bottom layers of the FRP laminated plates produced using VE resin were closer to the mold, and exhibited more shrinkage as the stacking number increased. In addition, this study discovered that during the experiment, the symmetry layer of the FRP laminated plate had a higher exothermic temperature than the bottom layer as a result of the symmetry layer’s ineffective heat dissipation. Therefore, the curing shrinkage of the symmetry layer resin was measured. The experiment results indicated that if the stacking number was between 10 and 30, the residual strain shrinkage of the symmetry layer was greater than that of the surface layer. However, because of the symmetric laminate, the residual strain of the symmetry layer did not increase when the temperature increased. Therefore, the greatest residual strain occurred at the surface of the bottom layer of the laminated plate with a stacking number of 40.

Protonic ceramic cells with thin BaZr0.8Y0.2O3-δ electrolytes for stable separation of H2 from H2–CO2 mixtures

Here we report selective separation of high-purity H 2 from a CO 2 -containing stream using protonic ceramic cells with thick Ni–BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ cathode substrates, thin BaZr 0.8 Y 0.2 O 3-δ electrolytes and thin Ni–BaZr 0.8 Y 0.2 O 3-δ anodes, as fabricated by the tape casting and tape lamination methods. Scanning electron microscopy observations show an overall micron porous structure for both electrodes with some nano-scale porosities inside Ni particles. The measured H 2 flux out of 3%-humidified 10% H 2 – 90% CO 2 at 700°C was 3.2 ml•cm −2 •min −1 at 0.90 V with a Faraday's efficiency of 97.8%. A preliminary 50-hour measurement in 10% H 2 – 90% CO 2 shows a slight increase in the pumping voltage from 0.96 to 1.03 V with a constant H 2 flux of 6.5 ml•cm −2 •min −1 and Faraday's efficiencies continuously above 97%, as enabled by excellent stability of BZY against CO 2 . • Protonic ceramic cells with thin BaZr 0.8 Y 0.2 O 3-δ electrolytes are fabricated. • Ni–BaZr 0.8 Y 0.2 O 3-δ anodes show promise for stable operation in 10%H 2 –90%CO 2 . • The H 2 recovery rate from 10%H 2 –90%CO 2 is 3.2 ml•cm −2 •min −1 at 1.5 V.

Lamination method for improved polarization-leakage current relation in HfO2-based metal/ferroelectric/insulator/semiconductor structure

Ever since the ferroelectricity of complementary metal-oxide semiconductor (CMOS) compatible HfO2-based materials was discovered, numerous studies have been conducted on their ferroelectric (FE) properties and device applications. In particular, pure-HfO2 FE materials without external doping have attracted considerable attention owing to their excellent robustness against variation because variations that appear in conventional doped-HfO2 FEs are not observed in electrical characteristics induced by dopant fluctuations in pure-HfO2 FEs. Studies on metal/FE/insulator/semiconductor (MFIS) stack are required to apply the ferroelectricity of pure-HfO2 to memory devices that are completely compatible with Si-based CMOS processes. In pure-HfO2 based MFIS stacks, the polarization tends to reduce with increasing thickness of the HfO2, although the leakage current diminishes. To overcome the tradeoff between the polarization and leakage current with respect to the thickness of the HfO2, an Al2O3 layer was inserted between the HfO2 layers to form a laminated FE structure. By employing the laminated FE, leakage current was effectively suppressed by the Al2O3 and lower HfO2 layers, and polarization was enhanced by the FE sum of the upper and lower HfO2 layers. Therefore, an MFIS structure with maximized polarization and minimized leakage current was successfully demonstrated using laminated FE. In addition, the feasibility of the proposed MFIS with laminated FE for nonvolatile memory device applications was confirmed by verifying the multistate operations of a FE tunnel junction.

Evaluation of internal fit of press ceramic and porous structured cobalt–chromium crown fabricated by additive manufacturing

The purpose of this in vitro study is to fabricate a novel metal-ceramic prosthesis with a porous structure, to compensate for the disadvantages associated with the design of existing prostheses, and to measure the internal fit of this prosthesis. In this in vitro study, the mandibular first molar was scanned from the dental computer-aided-design to design a 3 mm porous structure frame. The frame was produced using the lamination method and fired in a pressed ceramic. For comparison, pore-free specimens were fabricated by selective laser sintering (SLS) as described above, and porous specimens were fabricated by casting (total n = 30). The internal fit was then measured using a digital microscope (at 100× magnification), and the data were analyzed using one-way ANOVA (α = 0.05). The total mean internal discrepancies for each group were 42.32 ± 22.50 μm for the porous structure SLS group (PS-group), 107.54 ± 38.75 μm for no-porous casting group (group), and 121.36 ± 50.19 μm for the no-porous SLS group (group), with significant differences (P < 0.05) among all groups. The internal discrepancies of porous structure crown fabricated by SLS were smaller than that of no-porous crown fabricated by casting and SLS. Based on these laboratory findings, further studies should be conducted to evaluate the feasibility of the newly designed porous structure and press ceramic prosthesis to determine whether they can be applied in clinical practice.

Lamination methods for the fabrication of perovskite and organic photovoltaics.

Perovskite solar cells (PSCs) have shown rapid progress in a decade of extensive research and development, aiming now towards commercialization. However, the development of more facile, reliable, and reproducible manufacturing techniques will be essential for industrial production. Many lamination methods have been initially designed for organic photovoltaics (OPVs), which are conceptually similar to PSCs. Lamination could provide a low-cost and adaptable technique for the roll-to-roll production of solar cells. This review presents an overview of lamination methods for the fabrication of PSCs and OPVs. The lamination of different electrodes consisting of various materials such as metal back contacts, photoactive layers, hole transport layers (HTLs), and electron transport layers (ETLs) is discussed. The efficiency and stability of the laminated devices are also presented. Finally, the challenges and opportunities of laminated solar cells are discussed.

Testing for Wearability and Reliability of TPU Lamination Method in E-Textiles.

Electronic textiles (e-textiles) and wearable computing have been emerging increasingly during the last decade. Since the market interest and predictions have grown, the research into increasing reliability and durability of wearables and e-textiles is developing rapidly. The washability of different integration methods and resistance to mechanical stress are the main obstacles being tackled. However, the freedom of movement and overall comfort is still often overlooked during the development phase. It is essential to see the e-textile product as a whole and consider several aspects of user experience. This work will focus on developing and improving the thermoplastic polyurethane (TPU) lamination integration method for e-textiles. In the work, a stretchable copper-polyimide based circuit was laminated onto knit fabric using various TPU films and stacks. The study shares measurable characteristics to determine which material assembly and design would ensure the highest durability for the electronics part without losing its original textile softness, flexibility and stretchability.

New practical device structure for graphen-based electrochromic devices

In this study, we fabricate a simple, low-cost, high-efficiency, and easy-to-design electrochromic device. Multilayer graphene (MLG) samples were obtained by chemical vapor deposition method (CVD) at four different growth temperatures of 900 , 950 , 1000 , and 1050 ∘ C . Electrical and optical characterizations of MLG samples were carried out by transferring them to the polyvinyl chloride (PVC) surface by thermal lamination method. After the characterization of the samples the so called coplanar surface is produced in order to obtain an efficient electrochromic device consisting of a flexible graphene surface without an extra electrode Optical measurements show that threshold voltage for the change in the optical modulation is 2.5 V in the near-infrared region and that there exists an increase of 60 % just over 3 V value. Also, in the electrical characterization studies, a decrease of up to approximately 50 % of the layer resistance was seen. • Multilayer graphene thin films were obtained by CVD method. • The device structure consisting of the graphene surface, which we call the coplanar structure, was developed. • A low-cost, easy-to-build, high-efficiency, flexible electrochromic device has been designed”. • Experimental results show that there was an increase of 60% in optical modulation value after the 3 V value and a decrease of up to approximately 50% of the layer resistance.

Optimized design of hydraulic silicone pad for OCA lamination of bended cover window in OLED display

In this study, we report the results of a new experiment using a hydraulically enabled silicone pad for OCA bonding in a cover window with three edges bent with 3R curvature. The silicone pad was designed using computer simulation to set eight important parameters in the cross-section of the pad and to optimize the shape according to the change in the curvature and length of the parameters. The compression strength of the designed silicone pad was analysed using simulation based on a hydraulic load. In addition, the hydraulic silicone pad, which was designed and manufactured in an optimized shape, was adhered to a pad plate to enable hydraulic pressure without oil leakage or outflow, and the OCA lamination was performed. Thus, we developed an optimized hydraulic silicone pad lamination method based on computer simulation and experimental results and provided a solution that can overcome the problems.

Compressive characteristics of multi-layer warp-knitted spacer fabrics with various interfaces conditions

In this paper, three kinds of warp knitted spacer fabrics (WKSFs) with different thickness were superposed in different ways. Furthermore, the multi-layer WKSFs were treated by hot-melting nonwovens. The aim of the study is to compare the compressive characteristics of multi-layer WKSFs with different lamination methods and various interfaces conditions. The results show that the compressive stress-strain curves have a tendency during single flat plate compression, which could be divided into three stages: linear compression stage, yield stage and crushing stage. Due to the influence of the number of layers, the yield stage also could be divided into three small stages. While the stress-strain curves of some WKSFs treated with hot-melting nonwovens are slightly different from those of untreated WKSFs. In the fatigue compression test, all multi-layer WKSFs directly transition from the linear compression stage to the crushing stage. Compared with multi-layer WKSFs untreated, multi-layer WKSFs treated with hot-melting nonwovens have less deformation under the same load. In addition, the energy absorbed by WKSFs and the compressive resilience would be increased with the increase of the first layer thickness of the multi-layer WKSF.

Interlaminar damage assessment method of CFRP laminate based on Synchrosqueezed Wavelet Transform and ensemble Principal Component Analysis

The damage assessment of Carbon Fiber Reinforced Plastics (CFRP) laminate structure is very important to ensure the safety of the structure in service. Machine learning is a research hotspot in damage assessment of CFRP structures. However, there are problems such as noise interference, small number of training samples, and few damage types of training samples. In order to solve the above problems, the damage assessment method of CFRP laminate based on Synchrosqueezed Wavelet Transform and ensemble Principal Component Analysis was proposed. First, the damage feature extraction method based on Synchrosqueezed Wavelet Transform (SWT) and Singular Spectrum Analysis (SSA) was proposed to reduce the feature dimension and achieve effective extraction of damage features. Then, the damage assessment method based on ensemble Principal Component Analysis (PCA) was proposed to realize the damage assessment of CFRP structure. Finally, the simulation experiment was designed to verify the damage assessment results in the case of noise interference, small number of training samples, and few damage types of training samples. The results showed that the damage assessment method of CFRP laminate structure based on SWT, SSA and ensemble PCA was feasible. This paper provided a feasible method for evaluating the damage degree of CFRP laminate structure.