High‐Performance Flexible Pressure and Temperature Sensors with Complex Leather Structure

The ability of the skin to be pressure‐sensitive has prompted scientists to develop materials and equipment to simulate this function. Recently, flexible and stretchable artificial electronic skin has received increasing attention with its unique ability to detect subtle pressure changes. Pressure sensing is one of the key functions of electronic skin devices. Here, a stretchy and highly sensitive pressure sensor is developed that used a polydimethylsiloxane (PDMS) film with leather composite layer as flexible part. These features enable the sensor to accurately detect a variety of human activities, such as small finger movements and bending, pulse and so on. The sensor is found to have a good sensing signal for temperature. This feature provides great promise for sensors to detect temperature.     

UV‐Printable and Flexible Humidity Sensors Based on Conducting/Insulating Semi‐Interpenetrated Polymer Networks

Humidity sensors are of great interest in many fields because humidity plays a crucial role in several processes. Nevertheless, their application is often limited by the expensive fabrication and the stiffness of the substrates usually employed. In this work, novel UV‐curable and flexible humidity sensors based on semi‐interpenetrated polymer networks are fabricated. They can be prepared either as self‐standing sensors or applied on different bendable substrates. The fabrication consists of a simultaneous UV‐curing of an insulating network (acrylic or epoxy) and photopolymerization of conducting polypyrrole (PPy). The detection mechanism involves proton transfer on the PPy chains that can be macroscopically observed by electrical impedance variations. These devices show promising humidity‐sensing properties from 20 to 97% of relative humidity with a maximum response of about 180%. The dynamic sensing investigation proves that the recovery process can be tailored playing on the glass transition temperature and wettability of the films. The remarkable sensing capabilities of these sensors make them a valid alternative in many applications where printability and flexibility are required along with simple fabrication method consisting of one‐step synthesis.     

Durable,Sensitive, and Wide‐Range Wearable Pressure Sensors Based on Wavy‐Structured Flexible Conductive Composite Film

Flexible pressure sensors have potential applications in human motion monitoring and electronic skins. To satisfy the practical applications, pressure sensors with a high sensitivity, a low detection limit, a broad response range, and an excellent stability are highly needed. Here, a piezoresistive pressure sensor based on wavy‐structured single‐walled carbon nanotube/graphite flake/thermoplastic polyurethane (SWCNT/GF/TPU) composite film is fabricated by a prestretching process. Due to the random wavy structure, high conductivity, and good flexibility, the prepared sensor displays a low detection limit of 2 Pa, a wide sensing range of 0–60 kPa, and a high sensitivity of 5.49 kPa^?1 for 0–50 Pa. Furthermore, the sensor shows a remarkable repeatability of over 1.1 × 10⁴, 9.0 × 10³, and 2.0 × 10³ pressure loading/unloading cycles at 50 Pa, 500 Pa, and 30 kPa, respectively, and a fast responsibility of 100–150 ms of loading response time and 400–600 ms of relaxation time. Therefore, the pressure sensor is successfully adopted to monitor both the large‐scale human activities (e.g., walk and jump) and the small‐scale signals (e.g., wrist pulse). Furthermore, a sensor array is assembled to map the weight and shape of an object, indicating its various potential applications including human–machine interactions, human health monitoring, and other wearable electronics.     

Self-Healing Polyurethane Elastomer Based on Crosslinked-Linear Interpenetrating Structure: Preparation,Properties, and Applications

Despite tremendous advances in the preparation of self-healing flexible strain sensor devices, it remains a great challenge to large-area synthesis, relatively high mechanical strength, and sensitive sensing properties into one self-healing materials system, which have received increasing interests because of their many potential applications. Herein, the design and synthesis of a crosslinked-linear interpenetrating structure polymer containing disulfide and hydrogen bonds is reported to address this conundrum. The resulting self-healable polymer is highly stretchable (up to 551.7%) with a high tensile strength (4.14 MPa) and excellent healing efficiency of similar to 90% at mild temperature without using any external reagents. Furthermore, a novel method for fabricating flexible sensor is also proposed to endow the resulted sensor with large-area (20 cm × 12 cm), low cost, and outstanding sensitivity to strain, which makes it very suitable for human motion monitoring applications. This work will provide afflatus on future design, fabrication, and application of self-healing flexible strain sensor devices.     

芳纶增强复合材料波纹夹层3D打印与力学性能研究

为解决波纹夹层结构传统制备方法存在的问题,采用熔融沉积(FDM)3D打印技术制备芳纶增强聚乳酸复合材料波纹夹层结构,并研究切片层高与打印温度对波纹夹层结构力学性能的影响。结果表明:当试样的切片层高为0.1 mm,打印温度为210℃时,复合材料波纹夹层结构的力学性能最好;试样的弯曲强度和冲击强度与切片层高呈负相关;随着打印温度的升高,试样的弯曲强度和冲击强度呈现先增大后减小的趋势。通过分析复合材料电镜图发现,切片层高的降低,有利于芳纶与聚乳酸基体的结合。     

Self‐Powered Flexible Sensor Based on the Graphene Modified P(VDF‐TrFE) Electrospun Fibers for Pressure Detection

Polymer P(VDF‐TrFE) has been extensively applied in modern flexible electronics, such as nanogenerators and pressure sensors. In this study, a repolarization method is proposed to exploit the piezoelectric properties of the P(VDF‐TrFE) electrospinning film modified by the reduced graphene oxide (rGO). Then, the repolarized composite film is applied as the self‐powered flexible pressure sensor. Notably, the piezoelectric output voltage and current of the repolarized composite film are up to 1.5 V and 0.125 µA, respectively. Typically, the piezoelectric voltage of the composite film is three times as high as that of the pure spinning film. Meanwhile, this composite film also exhibits piezoresistive effect, which is ascribed to the 3D network structure of the electrospun nanofibers. In addition, the highest piezoresistive sensitivity of the pressure sensor is 0.072 kPa^?1. To sum up, the pressure sensor fabricated in this study allows to simultaneously detect the static and dynamic pressure loads, which thereby has great application potentials in electronic skins (e‐skins) for human motion monitoring, such as motion state and finger bending.     

机器人柔性压力传感皮肤的研究开发现状

机器人柔性压力传感皮肤是集轻柔化、微小化、可穿戴、感应灵敏与集成度高于一体的智能皮肤。综述了几种新型柔性压力传感集成技术与基于纺织结构集成的柔性压力传感技术相关方面的研究与应用,总结了目前机器人柔性压力传感皮肤的传感材料、传感技术原理与实际应用的研究现状,最后对机器人柔性压力传感皮肤的开发与使用领域进行了展望。     

压力管道柔性设计及金属波纹管膨胀节选用

简述压力管道柔性设计的目的和方法,重点介绍金属波纹管膨胀节的选用,及在安装和使用中应注意的问题。     

High‐Performance Flexible Sensors of Self‐Healing,Reversibly Adhesive,and Stretchable Hydrogels for Monitoring Large and Subtle Strains

Flexible sensors are becoming required in heath monitoring and human–machine interfaces, but it is still a challenge to develop flexible sensors with integrated high performances. Herein, high‐performance flexible sensors are fabricated that are self‐healing, reversibly adhesive, and utilizing stretchable hydrogels, which are composed of a pluronic F127 diacrylate (F127DA) cross‐linked poly(acrylic acid) (PAA) network and polydopamine (PDA), and further cross‐linked by Fe³⁺. The unique structure endows the resulting hydrogels (PAA‐PDA‐Fe³⁺ hydrogels) excellent self‐healing property, reversible adhesion property, mechanical stretchability, and electrical conductivity. On the basis of the excellent properties of PAA‐PDA‐Fe³⁺ hydrogels, flexible sensors with large sensing range (0–575%), high sensitivity (GF = 6.31), low response time (0.25 s), and excellent robustness (>500 cycles) are assembled and further applied in detecting both large and subtle strains induced by human motions and water ripple. Overall, this work not only provides an alternative clue to construct multi‐functional hydrogels, but also offers a new kind of high‐performance materials for flexible electronic devices, especially those for health monitoring and human–machine interface.     

多层包扎式结构在大型中压容器上的运用

在大型中压容器上采用多层包扎式结构进行了尝试。认为多层包扎式结构的适用范围不应限于高压容器,而是也应适用于厚壁的中压容器。当中压容器的筒体厚度比较大时,制造企业可以从容器结构、材料采购、制造装备、焊接、无损检测等方面综合考虑,是否采用多层包扎式结构。另外,当容器的简体厚度比较大,且对与介质接触的壳体材质有特殊要求时,采用多层包扎式结构,内筒可用厚度较小的特殊材料或复合板,层板采用普通材料,能降低设备造价。     

Low-Cost,Highly Sensitive,and Flexible Piezoresistive Pressure Sensor Characterized by Low-Temperature Interfacial Polymerization of Polypyrrole on Latex Sponge

Piezoresistive pressure sensors based on sponge are widely concerned because of their wide strain range, convenient signal acquisition, and good compressibility, yet it is still a challenge to acquire sponge-based pressure sensors with low cost and excellent sensing performance. Herein, low-priced FeCl₃^.6H₂O and pyrrole (Py) are dispersed in deionized water to form FeCl₃^.6H₂O/Py solution. Commercial latex sponge is impregnated into this solution to prepare conductive polypyrrole/latex (PPy/latex) sponge through low-temperature interfacial polymerization. The surface of latex sponge is covered by the micro-wrinkled PPy, which endows the PPy/latex sponge with a certain electrical conductivity. The specific porous structure and high elasticity of the latex sponge are the basic conditions for PPy/latex sponge excellent piezoresistive behaviors. PPy/latex sponge based piezoresistive pressure sensor shows high sensitivity (0.084 kPa⁻¹ at below 3.12 kPa), wider sensing range (0–85.0%) and long durability over 3800 s (1800 cycles). At the same time, the ability of the PPy/latex sponge based piezoresistive pressure sensor to monitor human movement has been successfully evaluated in some application scenarios, such as bending fingers, grabbing objects, tiptoe rising, and crouching.     

调温调湿抗菌净味柔性内墙腻子的研制

以零VOC弹性乳液为成膜物,硅藻土为主要填料,定型相变储能材料为功能填料,配用负离子抗菌添加剂、抗裂剂、多种助剂,制备成调温调湿抗菌净味柔性腻子。该腻子具有保温隔热、调温控温、吸湿放湿、抗菌防霉、释放负离子、清新空气等功能。     

Flexible nanoscale co-continuous structures prepared by controlled crazing of ethylene-octene elastomers and in-situ polymerization of conductive networks

An approach based on controlled crazing and post-polymerization was used to incorporate a nanoscaled conductive co-continuous network into commercial ENGAGE™ Polyolefin Elastomers (POEs). Three POE films of differing crystallinity and phase morphology were stretched in a reactive mixture of acrylic polymerization precursors that possessed an affinity for the olefinic materials and acted as a surface-active agent for craze promotion. As a result, a rigid acrylic hydrogel phase was grown in the void space associated with crazing, which prevented the formed channels from collapsing after mechanical stresses were removed. The hydrogel phase offered ion conductivity properties to the POE. Simply replacing the acrylic monomer with an aniline emulsion for polymerization did not lead to the same outcome in terms of a continuous network; the materials became insulative after the removal of mechanical stresses due to fragmentation of the polyaniline channels from the unrestrained elastic relaxation of the POE. This problem was overcome by solution-casting POE with polycaprolactone (PCL) into films and, subsequently, partially dissolving and leaching PCL from the blend while a sample was stretched in an aniline emulsion medium containing formic acid. The residual PCL left in the crazes reinforced the polyaniline to prevent fragmentation, allowing the formation of a highly electron-conductive secondary phase.     

Flexible strain sensors with high sensitivity and large working range prepared from biaxially stretched carbon nanotubes/polyolefin elastomer nanocomposites

Flexible strain sensors are a new generation of flexible and stretchable electronic devices that attracted increasing attention due to their practical applications in many fields. However, maintaining a wide detectable strain range while improving the sensitivity of flexible strain sensors remains challenging. In this study, flexible strain sensors with a large working range based on biaxially stretched carbon nanotubes (CNTs)/polyolefin elastomer (POE) nanocomposites were fabricated. Biaxial stretching was demonstrated to enhance the uniform dispersion and orientation of CNTs, thereby improving the performance of sensors. The optimal stretching ratios (SRs) of nanocomposites were investigated and the data revealed an increment in the sensitivity of sensors with SRs, while the working range first increased after biaxial stretching and decreased at higher SRs. Compared to the 9 wt% CNT/POE-1.0 sensor with a gauge factor (GF) value of 2.37 and a detectable range of 0.5%–230%, the CNT/POE-2.0 sensor exhibited an enhanced sensitivity (GF = 3935.12) coupled with a wider detectable range (0.5%–710%) and better stability. Besides, CNT/POE-2.0 sensor also achieved the monitoring of head movements, mouth opening, facial expression, and physiological signals, showing a potential for use in wearable electronic products.     

酚醛面板蜂窝夹层结构的面-芯界面优化及其对弯曲和剪切性能的影响

为了提高安全性和经济效益,酚醛面板蜂窝夹层结构在内饰领域的应用越来越广泛.但是在共固化工艺中,面板用酚醛预浸料和环氧胶膜存在相容性问题,易产生弱界面.本文通过调整胶膜的单位面积质量(面重)实现了面-芯界面的优化,结果表明,滚筒剥离强度随环氧胶膜面重的增大先提高后下降.基于夹层结构四点弯曲和平板剪切试验的载荷位移曲线以及...     

Mechanically Robust,Tough, and Self‐Recoverable Hydrogels with Molecularly Engineered Fully Flexible Crosslinking Structure

How to reasonably fabricate polymer network for high performance hydrogels is a critical issue but remains a challenge. This work reports an approach to high performance hydrogels by molecularly engineering fully flexible crosslinking (ffC) network. A model network cross‐linked by fully flexible crosslinking points of triblock copolymer micelles and ionic interactions is fabricated. Due to the unique structure, the resulting ffC hydrogels are mechanically robust, tough, and self‐recoverable. For as‐prepared ffC hydrogels, a tensile stress more than 3.5 MPa can be achieved and the energy dissipation can reach up to 6.61 MJ m⁻³ at the tensile strain of 125%. Moreover, ffC hydrogels fabricated under constant strain can achieve an energy dissipation ability up to 11.63 MJ m⁻³ at the tensile strain of 100% and a tensile stress of 17.57 MPa. Based on these results, a dynamic molecular mechanism in the ffC hydrogel network under tensile deformation is proposed. The high performances of the ffC hydrogels can be possibly attributed to the sequential breakage and energy dissipation of the flexible crosslinking points and the easily accessible polymer chain orientation during tensile deformation.

     

不等极孔纤维缠绕球形压力容器的结构设计与性能

本文概要介绍了不等极孔纤维缠绕形压力容器的结构形式，受力状态及纤维铺层设计方法，提出了纤维强度发挥系数与在球体位置关系的函数概念，通过改变特征点的强度发挥系数，可以方便地进行球形容器的结构优化设计。     

低供热源变压再生脱碳工艺的运行及特点

采用低供热源变压再生工艺对原脱碳再生系统进行改造。改进后,不仅提高了生产能力,而且降低了脱碳液再生能耗。     

用激光粒度分析仪检测细粒径SiO2基相变调湿复合材料的粒度分布

以SiO2为载体、棕榈醇-棕榈酸-月桂酸为相变材料,采用溶胶-凝胶法制备细粒径SiO2基相变调湿复合材料,以中位径(d50)为评价指标,采用激光粒度分析仪研究了溶液溶质浓度、超声时间、超声频率及分散介质对材料粒度的影响. 结果表明,激光粒度分析仪可用于检测SiO2基相变调湿复合材料的粒度分布,水对材料的分散效果比乙醇好,以水为分散介质,材料最佳溶质浓度为5~10 g/L,最佳超声时间为15 min以上,最佳超声功率大于400 W.     

低温撞击破碎高能发射药结构特征与高压燃烧性能研究

在-40℃下,通过落锤撞击制备了不同破碎程度的DAGR125和NR11发射药,利用染料吸附量表征了发射药的破碎程度,结合密闭高压爆发器实验,分析了破碎发射药结构特征与高压燃烧特征的关系。结果表明,随着小颗粒破碎发射药的增加,动态活度变化率在燃烧初始阶段发生转折。当破碎程度较小时,初始动态活度、染料吸附量均可衡量发射药初始燃面和破碎程度;当破碎程度较大时,利用传统方法获取的初始动态活度明显小于实际值,不适合用来表征初始燃面,而染料吸附量法更为准确。初始动态活度变化规律显示,当落锤高度大于60cm时,发射药药粒的破碎程度快速增加;动态活度变化规律显示,落锤高度分别大于23.0cm和23.1cm时,DAGR125和NR11破碎发射药整体燃烧过程由增面性转变为减面性。