Stretchable carbon nanotube conductors and their applications

Stretchable electronics has evolved rapidly in the past decade because of its promising applications, as electronic devices undergo large mechanical deformation (e.g., bending, folding, twisting, and stretching). Stretchable conductors are particularly crucial for the realization of stretchable electronic devices. Therefore, tremendous efforts have been dedicated toward developing stretchable conductors, with a focus on conductive material/polymer composites. This review summarizes the recent progress in stretchable conductors and related stretchable devices based on carbon nanotubes (CNTs), which was enabled by their outstanding electrical and mechanical properties. Various strategies for developing highly stretchable conductors that can deform into nonplanar shapes without significant degradation in their electronic performance are described in terms of preparation processes. Finally, challenges and perspectives for further advances in CNT-based stretchable conductors are discussed.     

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.     

Self-Healing Materials for Electronics Applications

Self-healing materials have been attracting the attention of the scientists over the past few decades because of their effectiveness in detecting damage and their autonomic healing response. Self-healing materials are an evolving and intriguing field of study that could lead to a substantial increase in the lifespan of materials, improve the reliability of materials, increase product safety, and lower product replacement costs. Within the past few years, various autonomic and non-autonomic self-healing systems have been developed using various approaches for a variety of applications. The inclusion of appropriate functionalities into these materials by various chemistries has enhanced their repair mechanisms activated by crack formation. This review article summarizes various self-healing techniques that are currently being explored and the associated chemistries that are involved in the preparation of self-healing composite materials. This paper further surveys the electronic applications of self-healing materials in the fields of energy harvesting devices, energy storage devices, and sensors. We expect this article to provide the reader with a far deeper understanding of self-healing materials and their healing mechanisms in various electronics applications.     

自修复超疏水材料的制备及功能化研究进展

该文归纳了近年来自修复超疏水材料的研究进展，总结了外援型和本征型自修复超疏水材料的制备方法，并介绍了功能化自修复超疏水材料及其应用，最后指出了自修复超疏水材料现阶段所面临的挑战和未来的发展方向。与普通超疏水材料相比，自修复超疏水材料具有优良的表面稳定性和循环使用性，其使用寿命得到明显延长。此外，将自修复超疏水材料功能化，还能够进一步扩大其使用范围。随着科学技术的发展，自修复超疏水材料必将在电子电器、医疗卫生、人工智能、海水淡化等众多领域中发挥关键性作用。     

Organic materials for organic electronic devices

In recent years, organic electronic devices which use organic materials as an active layer have gained considerable interest as light-emitting devices, energy converting devices and switching devices in many applications. In these organic electronic devices, the organic materials play a key role of managing the device performances and various organic materials have been developed to improve the device performances of organic electronic devices. In this paper, recent developments of organic electronic materials for organic light-emitting diodes and organic solar cells were reviewed.     

Graphene‐based electrodes for flexible electronics

As ‘flexibility’ has emerged as an important issue in next‐generation electronics, many efforts to find new classes of materials have been devoted to realizing stretchable, bendable and foldable electronic devices. For these devices to be realized, graphene has been considered as one of the most promising candidates for flexible electrodes due to its extraordinary electrical, optical and mechanical properties. Particularly, recent developments in the fabrication and modification of graphene point to a bright future for graphene electrodes in flexible electronics. This mini‐review summarizes the recent progress in graphene films as flexible electrodes for various applications such as solar cells, organic light‐emitting diodes, touchscreens, transistors and supercapacitors. © 2015 Society of Chemical Industry     

Nanomaterials for bioelectronics and integrated medical systems

Biomedical electronic devices integrated with specific human body parts have attracted considerable attention because they present significant breakthroughs to solve various clinical challenges. Recent innovations in soft nanomaterial assemblies, novel device design strategies, and clinically relevant system-level applications have accelerated the rapid growth in this research field. In particular, novel biomedical functionalities, such as extraordinary sensitivity in diagnosis and outstanding therapy performance, could be achieved through wearable, implantable, and minimally invasive bioelectronics. Monolithic integration of functional nanomaterial assemblies with flexible and stretchable device platforms has enabled these breakthroughs. This review first presents a brief history and then provides more details of recent advancements in nanomaterial assemblies and their applications to soft bioelectronics. Important technological advances to solve unmet clinical challenges are presented by leveraging soft bioelectronics toward the next-generation medical systems.     

Biomass-derived materials for electrochemical energy storages

During the past decade humans have witnessed dramatic expansion of fundamental research as well as the commercialization in the area of electrochemical energy storage, which is driven by the urgent demand by portable electronic devices, electric vehicles, transportation and storage of renewable energy for the power grid in the clean energy economy. Li-secondary batteries and electrochemical capacitors can efficiently convert stored chemical energy into electrical energy, and are currently the rapid-growing rechargeable devices. However, the characteristic (including energy density, cost, and safety issues, etc.) reported for these current rechargeable devices still cannot meet the requirements for electric vehicles and grid energy storage, which are mainly caused by the limited properties of the key materials (e.g. anode, cathode, electrolyte, separator, and binder) employed by these devices. Moreover, these key materials are normally far from renewable and sustainable. Therefore great challenges and opportunities remain to be realized are to search green and low-cost materials with high performances. A large number of the properties of biomass materials-such as renewable, low-cost, earth-abundant, specific structures, mechanical property and many others-are very attractive. These properties endow that biomass could replace some key materials in electrochemical energy storage systems. In this review, we focus on the fundamentals and applications of biomass-derived materials in electrochemical energy storage techniques. Specifically, we summarize the recent advances of the utilization of various biomasses as separators, binders and electrode materials. Finally, several perspectives related to the biomass-derived materials for electrochemical energy storages are proposed based on the reported progress and our own evaluation, aiming to provide some possible research directions in this field.     

Graphene-based flexible and stretchable thin film transistors

Graphene has been attracting wide attention owing to its superb electronic, thermal and mechanical properties. These properties allow great applications in the next generation of optoelectronics, where flexibility and stretchability are essential. In this context, the recent development of graphene growth/transfer and its applications in field-effect transistors are involved. In particular, we provide a detailed review on the state-of-the-art of graphene-based flexible and stretchable thin film transistors. We address the principles of fabricating high-speed graphene analog transistors and the key issues of producing an array of graphene-based transistors on flexible and stretchable substrates. It provides a platform for future work to focus on understanding and realizing high-performance graphene-based transistors.     

An innovative synergy between solution electrospinning process technique and self-healing of materials. A critical review

An overview of recent advances related to self-healing (SH) of materials and solution electrospinning (SEP) is provided. SH agents (SHAs) in electrospun form seems to be one of the most promising approaches for SH and exhibit an increasing trend for a wide range of applications. The aim of the current review paper is to report contributions and advances related to SH of materials by using SHAs in electrospun form and provide insights for further improvement of this promising technology. More specifically, this paper contains investigations in which the SHAs or the SHA containers were exclusively prepared by SEP.     

Design and properties of dynamic self-healing polyurea molecule based on disulfide bonds

Although thermosetting polymer materials have excellent mechanical properties, they are less self-healing, recycling than thermoplastic polymer materials, which may cause a serious waste of resources. Herein, a series of polyurea materials with high mechanical strength, good properties of self-healing and recycling are prepared by adjusting the ratio of polyether polyol and introducing disulfides into the synthesis of polyurea prepolymer in an innovative way. The composite polyurea (FHPUA) materials with tensile strength over 47 MPa and elongation at break of 720% are prepared. The experimental results show that by adjusting the content of aromatic disulfide, the tensile strength is further increased to 52 MPa, and the heat resistance of the material is improved. Through five self-healing experiments, the surface of the material recovers as before even after continuous heating at 70°C for 1 h. In addition, the tensile strength of the material recovers 86.56% and the elastic modulus recovers 70.21% after four recycling experiments. In practical application, it is expected to fill the shortcomings of traditional polyurea such as micro cracks, short service life and poor performance, and have great potential applications in the fields of coating layer of heavy-duty conveyor belts, encapsulation film of electronic devices and building facade coating.     

微胶囊固化剂的制备方法及应用

介绍了微胶囊固化剂的特点及固化机理,对微胶囊固化剂的制备方法及近年来研究进展进行了综述。同时,介绍了微胶囊固化剂在潜伏性预浸料、修复用复合材料以及半导体器件封装材料等领域的应用,并对其前景作了展望。     

Flexible and sensitive piezoresistive electronic skin based on TOCN/PPy hydrogel films

In recent years, the wearable electronic skin (E-skin) has attracted more and more attention due to high sensitivity, good portability and flexibility. In this work, we used the 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-oxidized cellulose nanofibril (TOCN) as the substrate, and used the in-situ polymerization method to introduce polypyrrole (PPy) into the TOCN substrate. Then, the nylon gauze was used as microstructure template to prepare a TOCN/PPy E-skin with a surface microstructure. This E-skin possessed excellent sensing and mechanical properties. In the pressure range of 0–600 Pa, the sensitivity of E-skin was 3.13 kPa⁻¹. In addition, the E-skin exhibited ultrafast response/recovery time (≤10 ms), ultralow detection limit of 0.3 Pa, good stability (>9000 cycles) and mechanical strength of up to 117 MPa. Therefore, the TOCN/PPy E-skin has broad development prospects in the fields of artificial intelligence and health monitoring.     

Recent advances and prospect of cobalt based microwave absorbing materials

With the advances and extensive application of electromagnetic (EM) waves in electronic and communication devices. EM pollution has been identified as a threat to human health whereby EM interference also affects the proper functioning of electronic devices. Therefore, the fabrication of novel microwave absorbing materials (MAMs) has become important to mitigate EM pollution and protect humans as well as other nearby electronic devices. The use of sole cobalt as MAM has gained significant attention due to its EM properties and suitable saturation magnetization. However, large density, eddy current loss, and poor corrosion resistance are some of the factors that hinder its practical application as an ideal MAMs. In this paper, recent advances towards overcoming these challenges have been reviewed. In particular, ways of regulating the morphology and optimizing the EM properties of cobalt-based MAM. Furthermore, fabrication of high-performance lightweight absorbers with hierarchical structures and formation of cobalt-based hybrid MAM with other lossy materials are discussed. Several factors affecting the microwave absorption performance of cobalt-based MAM are further discussed. Finally, the present limitations as well as prospects are put forward to give a new insight into the design of improved cobalt-based MAM.     

本征型自愈合聚氨酯及其相关复合材料的研究进展

综述了近年来本征型自愈合聚氨酯材料的研究进展,包括共价和非共价化学自愈合聚氨酯,以及负载有纳米填充物的相关复合材料的应用.归纳了这些先进材料的发展进程以及赋予其自愈合特性的不同方法,介绍了自愈合聚氨酯领域的潜在应用、挑战和未来的发展前景.     

Tailored polymer-based nanorods and nanotubes by "template synthesis": From preparation to applications

Polymer nanotechnology allows manipulating materials microstructure, morphology and compositional variation on the nanometer scale. Thus, it is able to provide materials for many cutting edge applications, from photonics to medical devices to sensors. This article summarizes recent work on template-based fabrication and on the basic properties of one-dimensional polymeric nanostructures and their inherent advantages over their conventional counterparts. The chemistry and physics relevant for the design of these nanostructured materials are discussed and recent advances emphasized. In particular, highlighting the effects of nanoconfinement on material behavior and putting somewhat greater emphasis on molecular motions. Some examples of one-dimensional-based polymeric nanostructures with promising applications for example in the field of tissue engineering are also presented as well as some aspects concerning recyclability of the used templates.     

Radiation-grafted materials for energy conversion and energy storage applications

Polymer electrolyte membranes are key components in electrochemical power sources that are receiving ever-growing demand for the development of more efficient, reliable and environmentally friendly energy systems. Ongoing research is focusing on materials with high ionic conductivity and stability, at low cost. Among different methods, radiation-induced grafting is a universal attractive method for preparation of polymer electrolyte materials with tunable properties for various energy conversion and energy storage applications. This review addresses recent advances in the application of radiation-induced grafting techniques for the preparation of polymer electrolyte membranes/separators for emerging electrochemical devices such as fuel cells, batteries and supercapacitors. The challenges associated with the current state-of-the-art materials are highlighted, together with new directions that should be considered for future research.     

Thermal conductivity of polymer-based composites: Fundamentals and applications

Thermal management is critical to the performance, lifetime, and reliability of electronic devices. With the miniaturization, integration and functionalization of electronics and the emergence of new applications such as light emitting diodes, thermal dissipation becomes a challenging problem. Addressing this challenge requires the development of novel polymer-based composite materials with enhanced thermal conductivity. In this review, the fundamental design principles of highly thermally conductive composites were discussed. The key factors influencing the thermal conductivity of polymers, such as chain structure, crystallinity, crystal form, orientation of polymer chains, and orientation of ordered domains in both thermoplastics and thermosets were addressed. The properties of thermally conductive fillers (carbon nanotubes, metal particles, and ceramic particles such as boron nitride or aluminum oxide) are summarized at length. The dependence of thermal conductivity of composites on the filler loading, filler aggregate morphology and overall composite structure is also discussed. Special attention is paid to recent advances in controlling the microstructure of polymer composites to achieve high thermal conductivity (novel approaches to control filler orientation, special design of filler agglomerates, formation of continuous filler network by self-assembly process, double percolation approach, etc.). The review also summarizes some emerging applications of thermally conductive polymer composites. Finally, we outline the challenges and outlook for thermally conductive polymer composites.     

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.     

电子陶瓷材料研究的一些新进展

随着电子科学技术的发展，用作电子材料的陶瓷的研究和开发十分引人注目，许多工厂和科研人员正在研究开发电子陶瓷新材料、新工艺和新器件，以满足电子科学技术的发展对高性能陶瓷材料的要求。本文简要介绍了电子陶瓷系统中绝缘体、介电质、压电体及铁电薄膜材料及其制备工艺和应用方面的一些新进展。