Numerical Simulation of a Viscoelastic Thinning Process for Preparing Flexible Glasses by Redrawing Method

The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,transverse and longitudinal velocity distribution of the glasses with different compositions were studied.Furthermore,the influence of these factors on the width and thickness of the flexible glass plate was investigated.It is found that the internal and external heat exchange of glass has a dominant influence on the viscosity variation during the UTG forming process,which is inconsistent with the general viscosity-temperature dependence.The glass that first reaches the lower limit of forming viscosity can significantly resist the shrinking effect caused by surface tension,making the glass wider during the forming.If the original glass width remains unchanged,the glass thickness or feeding speed is reduced,wider and thinner flexible glasses can be produced.

Development of a High-PerformanceFlexible Substrate for Flexible Electronics:Joining TAC Films and an Ultra-Thin Glassby Using TEOS-DAC Synthesized by the Sol-Gel Method

A new flexible substrate for flexible electronics has been developed. The developed substrate consists of an ultra thin glass and TAC (triacethyl cellulose) film. An ultra thin glass and TAC film were joined with TEOS-DAC (TEOS: tetraethyl orthosilicate, DAC: diacethy cellulose) adhesive resin synthesized by sol-gel method by means of thermo-compression bonding. This substrate has high transparency in visible-light region (90%), high flexibility (torsion strength and bending strength) and high gas barrier characteristics due to an ultra thin glass. The newly-developed substrate is superior to the substrates fabricated with commercially available adhesive resin in the same way in characteristics of heat resistance, transparency and flexibility.

Direct growth of graphene films without catalyst on flexible glass substrates by PECVD

A hydrogen-plasma-etching-based plasma-enhanced chemical vapor deposition(PECVD)synthesis route without metal catalyst for preparing the graphene films on flexible glass is developed.The quality of the prepared graphene films is evaluated by scanning electron microscopy,x-ray photoelectron spectroscopy,high-resolution transmission electron microscopy,ultraviolet-visible spectroscopy,and electrochemical measurements.In a radio frequency(RF)power range of 50 W-300 W,the graphene growth rate increases with RF power increasing,while the intensity ratio of D-to G-Raman peak(I_(D)/I_(G))decreases.When the RF power is higher than 300 W,the I_(D)/I_(G)rises again.By optimizing experimental parameters of hydrogen plasma etching and RF power,the properties of as-prepared flexible graphene on glass are modulated to be able to achieve the graphene's transparency,good electrical conductivity,and better macroscopic uniformity.Direct growth of graphene film without any metal catalyst on flexible glass can be a promising candidate for applications in flexible transparent optoelectronics.

Study on Heating Uniformity of Pt-Rh Alloy Bushing for Producing Flexible Glass

The numerical simulation for temperature distribution of Pt-Rh alloy bushing was carried out using a thermal-electric module in ANSYS Workbench finite element analysis software.The effects of side wall thickness,plug thickness,the angle of two side walls and electrode structure on the uniformity of temperature distribution were investigated.Meanwhile,the contrastive analysis results of bushing with and without glass melt were discussed.The simulation results show that,when the homogeneous glass melt flows through bushing,the temperature difference between the center and both ends of bushing is decreased significantly,but the temperature distribution at both ends of bushing is still affected by heating non-uniformity of bushing.Compared with side wall thickness,plug thickness and the angle of two side walls,electrode structure plays a greater role in adjusting heating uniformity of bushing.

The Effective Surface Metallization of Hollow Glass Microspheres for Flexible Electromagnetic Shielding Film

The surface of hollow glass microspheres (HGMs) was roughened by a HCl+NH_(4)F strategy,which achieved a broken ratio as 16.10%,and then metallized by electroless plating by Co nanoparticles up to 90 wt% (abbreviated as Co-HGMs).The average grain size of Co was measured to range from 0.4 to 0.5 μm.Then Co-HGMs were mixed with liquid silicone rubber and xylene,and cured on a perspex plate applicable for flexible electromagnetic shielding.By attentive parameter optimization,a film about 0.836 mm in thickness was obtained with a density of 0.729 g/cm^(3),showing a shielding effectiveness of 15.2 dB in the X-band (8.2-12.4 GHz) at room temperature,which was ascribed to the formation of a conductive network of Co-HGMs inside the film.Simultaneously,the tensile strength of 0.89 MPa at an elongation ratio of 194.5% was also obtained,showing good mechanical properties and tensile strength.

Flexible one-dimensional photonic crystal films composed of chalcogenide glass and water-soluble polymer for curvature sensing

Curvature sensing plays an important role in structural health monitoring,damage detection,real-time shape control,modification,etc.Developing curvature sensors with large measurement ranges,high sensitivity,and linearity remains a major challenge.In this study,a curvature sensor based on flexible one-dimensional photonic crystal(1D-PC)films was proposed.The flexible 1D-PC films composed of dense chalcogenide glass and water-soluble polymer materials were fabricated by solution processing.The flexible 1D-PC film curvature sensor has a wide measurement range of 33-133 m-1and a maximum sensitivity of0.26 nm/m^(-1).The shift of the transmission peak varies approximately linearly with the curvature in the entire measurement range.This kind of 1D-PC film curvature sensor provides a new idea for curvature sensing and measurement.

Effect of Thermal Crosslink Conditions on Dynamic Mechanical Behaviors of Flexible Epoxy

The dynamic mechanical behavior of a new kind of flexible epoxy FE-1,which was crosslinked under four different thermal crosslink conditions,was studied.Dynamic mechanical measurement was carried out from 10 ℃ to 120 ℃,and loss factor,tan δ and the storagemodulus as functions of temperature were presented under five different frequencies of 0.1 Hz, 1 Hz,5 Hz,50 Hz and 100 Hz. The experimental results show that temperature has dramatic effects on the dynamic mechanical behavior of flexible epoxy. Compared with other common available epoxy, the flexible epoxy has higher loss factor over broad frequency and common temperature range. Activation energy corresponding to glass transition process of FE-1 was calculated from the temperature corresponding to tan 8 rna~ values, obtained at different measurement frequencies. The maximum value of loss factor is 0.75 and the Tg varies from 6 ℃ to 50 ℃, indicating the flexible epoxy can be used as damping polymer materials at common temperature or frequency range.

柔性玻璃的化学强化及其力学性能研究

具有高弯曲强度的柔性玻璃是柔性电子显示的重要组成部分,但柔性玻璃本质是脆性材料,因此其力学性能仍然不能满足使用要求。化学强化是提高柔性玻璃弯曲半径、抗划伤性等力学性能的有效途径,本文采用一步化学强化法,将90μm超薄高铝柔性玻璃在纯硝酸钾熔盐中进行强化,研究离子交换工艺对样品表面应力、维氏硬度及弯曲半径的影响规律。结果表明:在380℃进行1 h的离子交换后,样品的表面压应力达834.1 MPa,应力层深度为15.91μm,此时玻璃具有最佳的弯曲性能和耐划伤性;经化学强化后,90μm柔性玻璃的最小弯曲半径可由(29.8±0.73)mm降低至(6.94±0.99)mm;随着继续升高交换温度和延长时间,柔性玻璃的力学性能会有所降低。

两点弯曲下柔性玻璃变形和疲劳行为研究

基于两点弯曲法加载方式及原理,分析了柔性玻璃的弯曲变形及疲劳行为,推导了弯曲曲率半径、弯曲应力与板间距之间的定量关系,基于高周疲劳理论,建立了柔性玻璃的应力-寿命(S-N_f)模型。结果表明,两点弯曲作用下,柔性玻璃试样的厚度不会改变其弯曲挠曲线轨迹,通过调节板间距,可获得试验所需的试样弯曲曲率半径。忽略柔性玻璃厚度的影响,试样的弯曲曲率半径与板间距呈线性关系,弯曲最大拉应力与弯曲曲率半径成反比。选择的最小弯曲曲率半径R_(min)越大,试样疲劳寿命越高,最大弯曲曲率半径R_(max)值的增大并不会显著影响试样的弯曲疲劳次数。Basquin模型能够有效预测不同交变应力或不同弯曲曲率半径作用下柔性玻璃的弯曲疲劳寿命。

Subsurface damage and bending strength analysis for ultra-thin and flexible silicon chips

Subsurface damage(SSD) is an unavoidable problem in the precision mechanical grinding for preparing ultra-thin and flexible silicon chips. At present, there are relatively few studies on the relationship between SSD and the bending strength of ultra-thin chips under different grinding parameters. In this study, SSD including amorphization and dislocation is observed using a transmission electron microscope. Theoretical predictions of the SSD depth induced by different processing parameters are in good agreement with experimental data. The main reasons for SSD depth increase include the increase of grit size, the acceleration of feed rate, and the slowdown of wheel rotation speed. Three-point bending test is adopted to measure the bending strength of ultra-thin chips processed by different grinding conditions. The results show that increasing wheel rotation speed and decreasing grit size and feed rate will improve the bending strength of chips, due to the reduction of SSD depth. Wet etching and chemical mechanical polishing(CMP) are applied respectively to remove the SSD induced by grinding, and both contribute to providing a higher bending strength, but in comparison, CMP works better due to a smooth surface profile. This research aims to provide some guidance for optimizing the grinding process and fabricating ultra-thin chips with higher bending strength.

Functional plastic films:nano-engineered composite based flexible microwave antennas with near-unity relative visible transmittance

Microwave antennas are essential elements for various applications,such as telecommunication,radar,sensing,and wireless power transport.These antennas are conventionally manufactured on rigid substrates using opaque materials,such as metal strips,metallic tapes,or epoxy pastes;thus,prohibiting their use in flexible and wearable devices,and simultaneously limiting their integration into existing optoelectronic systems.Here,we demonstrate that mechanically flexible and optically transparent microwave antennas with high operational efficiencies can be readily fabricated using composite nanolayers deposited on common plastic substrates.The composite nanolayer structure consists of an ultra-thin copper-doped silver film sandwiched between two dielectric films of tantalum pentoxide and aluminum oxide.The material and thickness of each constituent layer are judiciously selected such that the whole structure exhibits an experimentally measured averaged visible transmittance as high as 98.94%compared to a bare plastic substrate,and simultaneously,a sheet resistance as low as 12.5Ω/sq.Four representative types of microwave antennas are implemented:an omnidirectional dipole antenna,unidirectional Yagi-Uda antenna,low-profile patch antenna,and Fabry-Pérot cavity antenna.These devices exhibit great mechanical flexibility with bending angle over 70°,high gain of up to 13.6 dBi,and large radiation efficiency of up to 84.5%.The proposed nano-engineered composites can be easily prepared over large areas on various types of substrates and simultaneously overcome the limitations of poor mechanical flexibility,low electrical conductivity,and reduced optical transparency usually faced by other constituent materials for flexible transparent microwave antennas.The demonstrated flexible microwave antennas have various applications ranging from fifth-generation and vehicular communication systems to bio-signal monitors and wearable electronics.

沿海大气环境环氧/玻璃鳞片复合涂层的开发及性能评价

通过对沿海地区石化企业的腐蚀环境分析,从涂料的树脂和玻璃鳞片的特性上进行分析和选择,有针对性地找出环氧玻璃鳞片涂料的主要成膜物质和玻璃鳞片合成涂料,并对涂料的氯离子渗透性、耐盐水性、耐盐雾、耐化性及相应的耐磨性、柔韧性、附着力等进行了测试,结果表明,各项性能指标均满足现行标准中沿海大气环境的性能要求,因而在沿海石化大气环境中具有广阔的应用前景。

柔性光伏支架场景下双面双玻光伏组件隐裂风险的实验研究

针对柔性光伏支架(下文简称为“柔性支架”)的结构响应导致双面双玻光伏组件产生隐裂的风险进行评估,首先介绍了柔性支架的结构响应及光伏组件隐裂判定标准,然后选择最适合在柔性支架场景下应用的主流双面双玻光伏组件作为实验对象,设计了可复现柔性支架结构响应工况的振动台,构建了柔性支架的结构响应与双面双玻光伏组件隐裂之间关系的实验模型;针对整体振动、翻转振动和扭曲振动3种工况下不同振动幅度、振动频率、振动次数的双面双玻光伏组件的隐裂情况进行实验分析,对柔性支架场景下实验工况与自然环境极端风荷载实际工况时双面双玻光伏组件的振动情况进行了对比,并验证了双面双玻光伏组件在全寿命周期内不发生隐裂的可靠性。研究结果表明:自然环境极端风荷载实际工况下,在柔性支架本身结构及光伏组件的边框结构不发生破坏的前提下,双面双玻光伏组件在全寿命周期内不会发生隐裂。

基板玻璃在新兴显示领域的发展与变革

基板玻璃是新兴显示技术的关键材料,其性能直接影响显示器的品质和成本。本文综述了基板玻璃在OLED、Mini-LED、Micro-LED等领域的应用现状与挑战,重点分析了尺寸大型化、轻薄化、高透光率、耐热性和柔韧性等方面亟待突破的技术难题。文章探讨了通过材料优化、先进加工、表面功能化和产业链协同创新等途径实现基板玻璃性能提升和成本控制的变革路径,并对未来研究方向提出建议,以期推动新兴显示产业的发展。

Flexible omnidirectional reflective film for CO_(2)laser protection

In this Letter,we presented a flexible omnidirectional reflective film made of polymer substrates and multiple alternating layers of two chalcogenide glasses for full-angle CO_(2) laser protection.The structure parameters of the device were simulated for theoretical prediction of best device structure.The reflector was fabricated by alternate thermal evaporation of two chalcogenide glasses with large refractive index contrast.The reflectivity was greater than 78%at 10.6μm.The flexible reflective film can provide an effective solution for full-angle CO_(2) laser protection of the moving targets,such as laser operators and mobile optical components,with potential applications for wearable laser protective clothing.

粘接性玻纤增强柔性管承压性能模拟及试验验证

与广泛使用的金属管道相比,粘接性玻纤增强柔性管具有耐腐蚀、柔性好、安装简单等特点,正在成为海洋油气输运新的管道型式。针对粘接性玻纤增强柔性管试验周期长、测试成本高以及试验结果受环境因素影响大等问题,采用Halpin-Tsai模型建立设计内径152 mm、设计内压30 MPa柔性管有限元模型,研究增强层玻纤带的缠绕角度、缠绕层数以及内衬层和外保护层壁厚等结构参数对柔性管承压性能的影响,结果表明:随着增强层玻纤带的缠绕角度、缠绕层数以及外保护层壁厚增加,柔性管的承压性能提高;随着内衬层壁厚增加,柔性管承压性能先提高后降低;确定理论条件下柔性管结构参数为增强层玻纤带缠绕角度±55°、增强层玻纤带缠绕层数40层、内衬层壁厚25 mm、外保护层壁厚25 mm。结合实际工程应用对结构参数进行优化,并开展爆破试验进行验证,最终得到柔性管实际结构参数为增强层玻纤带缠绕角度±55°、增强层玻纤带缠绕层数100层、内衬层最佳壁厚8 mm、外保护层最佳壁厚8 mm。

Ultra-sensitive flexible Ga_(2)O_(3)solar-blind photodetector array realized via ultra-thin absorbing medium

The quest for solar-blind photodetectors with outstanding optoelectronic properties and weak signals detection capability is essential for their applications in the field of imaging,communication,warning,etc.To date,Ga_(2)O_(3)has demonstrated potential for high-performance solar-blind photodetectors.However,the performance usually decays superlinearly at low light intensities due to carrier-trapping effect,which limits the weak signal detection capability of Ga_(2)O_(3)photodetectors.Herein,a Ga_(2)O_(3)solarblind photodetector with ultra-thin absorbing medium has been designed to restrain trapping of photo-generated carriers during the transporting process by shortening the carrier transport distance.Meanwhile,multiple-beam interference is employed to enhance the absorption efficiency of the Ga_(2)O_(3)layer using an Al/Al_(2)O_(3)/Ga_(2)O_(3)structure.Based on the ultra-thin absorbing medium with enhanced absorption efficiency,a 7×7 flexible photodetector array is developed,and the detectivity can reach 1.7×10^(15)Jones,which is among the best values ever reported for Ga_(2)O_(3)photodetectors.Notably,the performance of the photodetector decays little as the illumination intensity is as weak as 5 nW/cm2,revealing the capacity to detect ultra-weak signals.In addition,the flexible photodetector array can execute the functions of imaging,spatial distribution of light source intensity,real-time light trajectory detection,etc.Our results may provide a route to high-performance solar-blind photodetectors for ultra-weak light detection.

柔性AZO/NiCr/Ag/NiCr/AZO透明导电玻璃结构对性能的影响

目的室温制备柔性透明导电玻璃并提高其光电性能。方法采用直流磁控溅射法,以柔性玻璃为基底,在室温下沉积(Aluminum-doped ZnO,AZO)/NiCr/Ag/NiCr/AZO多层结构透明导电玻璃。通过探针轮廓仪测试、X射线衍射仪(X-ray diffraction,XRD)测试、拉曼光谱仪测试、分光光度计测量、四探针测试和霍尔效应测试,分别获得了样品的各层薄膜厚度、X射线衍射图谱、拉曼光谱、透光率、方块电阻和电学性能。经过参数优化,选取Ag膜厚度为3~15 nm的样品,研究Ag膜厚度对玻璃样品的结构特征及光电性能的影响。结果样品光电性能与Ag层厚度密切相关,随着中间Ag层厚度的增加,样品在380~760 nm波长范围内的平均光透光率先增加后降低,吸收边依次发生了红移,样品的方块电阻则随着Ag层厚度的增加单调减小。Ag膜厚度为12 nm的样品综合光电性能最佳,其平均透光率为82.4%,载流子浓度为8.32×10^(21) cm^(‒3),载流子迁移率为8.21 cm^(2)/(V·s),电阻率为9.15×10^(‒5)Ω·cm,方块电阻为8.8Ω/sq,品质因子可达16.4×10^(–3)Ω^(–1)。结论说明可以通过透明导电薄膜结合金属薄膜在室温下获得柔性透明导电玻璃,并具有较好的透光性能和导电性。

Unusual gradient stress induced superior room-temperature plasticity in brittle ferromagnetic bulk metallic glass

Ferromagnetic bulk metallic glasses(FBMGs)possess excellent soft magnetic properties,good corrosion resistance,and high strength.Unfortunately,their commercial utility is limited by their brittleness.In this work,we report the enhancement in the room-temperature plasticity during the compression(25%)and bending flexibility of Fe_(74)Mo_(6)P_(13)C_(7) FBMG by using water quenching.The high-energy synchrotron X-ray measurements,high-resolution transmission electron microscopy,three-dimensional X-ray microtomog-raphy,and finite element simulation were performed to reveal the origin.It was found that the M-shape profile of residual stress improves the mechanical properties of FBMGs,particularly their plasticity.The reversal of the heat-transfer coefficient and cooling rate from the'vapor blanket'to'nucleate boiling'transition during water quenching processing is the main cause of the unusual profile of residual stress in glassy cylinders.Encouraged by the progress in developing flexible silicate glasses,this work highlights a processing method to improve plasticity and surmount technical barriers for the commercialization of FBMGs.

橡胶分子链在玻璃纤维表面的接枝

采用分子结构中含不饱和双键的偶联剂对玻璃纤维进行表面处理 ,然后在玻璃纤维表面涂覆过氧化物引发剂 (BPO)及橡胶溶液 ,使橡胶分子链在引发剂的作用下与玻璃纤维表面的偶联剂进行接枝反应 ,在玻璃纤维表面接枝了一层橡胶分子链 ,初步分析了橡胶分子链在玻纤表面的反应机理 ,对几种橡胶 (EPDM、顺丁橡胶、丁苯橡胶、丁腈橡胶、氯丁橡胶 )