The performance enhancement in organic light-emitting diode using a semicrystalline composite for hole injection

A semicrystalline composite, 3, 4, 9, 10 perylenetetracarboxylic dianhydride （PTCDA） doped N,N＇-di（1-naphthyl）- N,N＇-diphenylbenzidine （NPB）, has been fabricated and characterized. An organic light-emitting diode using such a composite in hole injection exhibits the improved performance as compared with the reference device using neat NPB in hole injection. For example, at a luminance of 2000 cd/m2, the former device gives a current efficiency of 2.0cd/A, higher than 1.6cd/A obtained from the latter device. Furthermore, the semicrystalline composite has been shown thermally to be more stable than the neat NPB thin film, which is useful for making organic light emitting diodes with a prolonged lifetime.

Construction of 3D aerogels consisting of cellulose and BNNSs bridged by AgNPs for enhancing thermal and tribological properties of polyurethane composites

Waterborne polyurethane(WPU)is attracting widespread attention in the friction field,but pure WPU cannot meet the wear resistance requirements due to poor thermal and self-lubricating properties.Herein,a novel cellulose/BNNSs-AgNPs aerogel(CBAg)composed of zero-dimensional silver nanoparticles(AgNPs),onedimensional cellulose and two-dimensional boron nitride nanosheets(BNNSs)was successfully fabricated.Specifically,AgNPs were loaded onto the surface of BNNSs,which could serve as bridges to connect adjacent BNNSs.Cellulose was used to construct a 3D skeleton structure for stabilizing better dispersion of inorganic fillers.Finally,the thermal and tribological properties of CBAg-WPU were improved compared to pure WPU,with a 69%increase in thermal conductivity and an 89%reduction in wear rate.This was attributed to the load-bearing capacity of cellulose and outstanding thermal and lubricant capability of BNNSs-AgNPs.In addition,BNNSs and AgNPs inside the aerogel were transferred to the sliding interface and participated in the formation of high-quality friction transfer film,further endowing CBAg-WPU composites prominent tribological performance.Therefore,the novel design of 3D hybrid aerogels provided a promising avenue to improve the tribological performance of WPU composites.

Microwave absorption properties of Ag naowires/carbon black composites

The composite that can absorb the high-performance electromagnetic（EM） wave is constructed into a sandwiched structure composed of carbon black（CB）/ethylene-vinyl acetate（EVA） and Ag naowires（Ag NWs）. The Ag NWs sandwiched between two CB/EVA layers are used to improve the absorption properties of composite. The effects of EVA-to-CB weight ratio, concentration and diameter of Ag NWs with a thickness of 0.4 mm on microwave absorption are investigated.The results indicate that for an EVA-to-CB weight ratio of 1：3, Ag NW concentration of 1.0 mg/100 m L, and average diameter of 56 nm, the reflection loss（RL） of the composite is below-10 d B in a frequency range of 9.3 Ghz–18.0 GHz, with the minimum values of-40.0 d B and-25.6 d B at 13.5 GHz and 15.3 GHz, respectively. A finite element method（FEM）is used for calculating the RL of the composite. The calculated results are in agreement with the experimental data.

Polymer-based EMI shielding composites with 3D conductive networks:A mini-review

High-frequency electromagnetic waves and electronic products can bring great convenience to people’s life,but lead to a series of electromagnetic interference(EMI)problems,such as great potential dangers to the normal operation of elec-tronic components and human safety.Therefore,the research of EMI shield-ing materials has attracted extensive attention by the scholars.Among them,polymer-based EMI shielding materials with light weight,high specific strength,and stable properties have become the current mainstream.The construction of 3D conductive networks has proved to be an effective method for the prepara-tion of polymer-based EMI shielding materials with excellent shielding effective-ness(SE).In this paper,the shielding mechanism of polymer-based EMI shield-ing materials with 3D conductive networks is briefly introduced,with emphasis on the preparation methods and latest research progress of polymer-based EMI shielding materials with different 3D conductive networks.The key scientific and technical problems to be solved in the field of polymer-based EMI shielding materials are also put forward.Finally,the development trend and application prospects of polymer-based EMI shielding materials are prospected.

Surface modification of calcium carbonate:A review of theories,methods and applications

Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompatibility.Nevertheless,in order to obtain the good filling effect,calcium carbonate needs to be surface modified by organic molecules so as to enhance the dispersion and compatibility within the composites.This review paper systematically introduces the theory,methods,and applications progress of calcium carbonate with surface modification.Additionally,the key factors that affect the properties of the composites as well as the current difficulties and challenges are highlighted.The current research progress and potential application prospects of calcium carbonate in the fields of plastics,rubber,paper,medicine and environmental protection are discussed as well.Generally,this review can provide valuable reference for the modification and comprehensive utilization of calcium carbonate.

Recent progress on multifunctional electromagnetic interference shielding polymer composites

The explosive development of electronic devices and wireless communication technology gives rise to the issue of electromagnetic pollution,known as electromagnetic interference(EMI).The accumulation of undesirable electromagnetic radiation in space disturbs the normal function of unshielded electronic appliances and poses seriously threat to human health.Thus,the development of EMI shielding materials have emerged to solve the grim problem.Considering the complex application contexts,EMI shielding materials have evolved from traditional single-function to multi-functions to meet the ever-increasing application requirements in recent few years.This paper provides detailed insight into the current re-search status and future challenges in the advancement of polymer-based EMI shielding materials with various functions.First,the basic theory of EMI shielding,factors influencing results and the dominating characterization technologies for EMI shielding properties are summarized.Then,the comprehensive descriptions of the seven types of multifunctional EMI shields are provided with respect to their structures,fabrication methods and specific functions.Meanwhile,the corresponding critical scientific and technical issues are proposed.Based on our comprehensive analysis,the main challenges in the development of multifunctional EMI shielding materials are presented.This review aims to provide some guidance and inspire more efforts toward functional EMI shielding material research to satisfy the growing requirements for next-generation electronic systems.

半晶聚合物基复合材料的界面结晶行为

半晶聚合物基复合材料界面处常形成横晶与杂化串晶。综述了近年来关于界面结晶的研究进展。重点分析了横晶与杂化串晶的制备方法及形成机制,并详细讨论了界面结晶的形成对复合材料力学性能的影响。最后对未来的研究方向进行展望。

Tunable patterning of microscale particles using a surface acoustic wave device with slanted-finger interdigital transducers

Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible polyethylene glycol diacrylate(PEGDA)fluid through a designed surface acoustic wave(SAW)device with slanted-finger interdigital transducers(SFITs).By applying signals of different frequencies,the SFITs can excite SAWs with various wavelengths to pattern the microscale particles.The structural design and working principle of the SAW device with SFITs are firstly presented.To investigate the generation of standing SAWs and pressure field distributions of the SAW device with SFITs,a numerical model was developed.Simulation results showed that different strip-shape patterned pressure fields can be generated,and the period and width of adjacent strips can be adjusted by changing the frequencies of the excitation signals.Experiments were performed to verify that the microscale particles in the PEGDA solution can be successfully patterned into strip-shape patterns with various positions,periods,and widths.The results obtained in this study demonstrate that the developed method of using an SAW device with SFITs can be used for tunable patterning of microscale particles in solutions,and shows great potential for biomedical and microfluidic applications.