The Polymer Physics of Multiscale Charge Transport in Conjugated Systems

Conjugated polymers are promising candidates for next‐generation low‐cost flexible electronics. Field‐effect transistors comprising conjugated polymers have witnessed significant improvements in device performance, notably the field‐effect mobility, in the last three decades. However, to truly make these materials commercially competitive, a better understanding of charge‐transport mechanisms in these structurally heterogeneous systems is needed for providing systematic guides for further improvements. This review assesses the key microstructural features of conjugated polymers across multiple length scales that can influence charge transport, with special attention given to the underlying polymer physics. The mechanistic understanding from collective experimental and theoretical studies point to the importance of interconnected ordered domains given the macromolecular nature of the polymeric semiconductors. Based on the criterion, optimization to improve charge transport can be broadly characterized by efforts to (a) promote intrachain transport, (b) establish intercrystallite connectivity, and (c) enhance interchain coupling. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1559–1571     

Imide-Functionalized Polymer Semiconductors

Imide-functionalized π-conjugated polymer semiconductors have received a great deal of interest owing to their unique physicochemical properties and optoelectronic characteristics, including excellent solubility, highly planar backbones, widely tunable band gaps and energy levels of frontier molecular orbitals, and good film morphology. The organic electronics community has witnessed rapid expansion of the materials library and remarkable improvement in device performance recently. This review summarizes the development of imide-functionalized polymer semiconductors as well as their device performance in organic thin-film transistors and polymer solar cells, mainly achieved in the past three years. The materials mainly cover naphthalene diimide, perylene diimide, and bithiophene imide, and other imide-based polymer semiconductors are also discussed. The perspective offers our insights for developing new imide-functionalized building blocks and polymer semiconductors with optimized optoelectronic properties. We hope that this review will generate more research interest in the community to realize further improved device performance by developing new imide-functionalized polymer semiconductors.     

Multisegmented one-dimensional nanorods prepared by hard-template synthetic methods

In the science and engineering communities, the nanoscience revolution is intensifying. As many types of nanomaterials are becoming more reliably synthesized, they are being used for novel applications in all branches of nanoscience and nanotechnology. Since it is sometimes desirable for single nanomaterials to perform multiple functions simultaneously, multicomponent nanomaterials, such as core-shell, alloyed, and striped nanoparticles, are being more extensively researched. Nanoscientists hope to design multicomponent nanostructures and exploit their inherent multiple functionalities for use in many novel applications. This review highlights recent advances in the synthesis of multisegmented one-dimensional nanorods and nanowires with metal, semiconductor, polymer, molecular, and even gapped components. It also discusses the applications of these multicomponent nanomaterials in magnetism, self-assembly, electronics, biology, catalysis, and optics. Particular emphasis is placed on the new materials and devices achievable using these multicomponent, rather than single-component, nanowire structures.     

Rational Design of Poly(2,7‐Carbazole) Derivatives for Photovoltaic Applications

A reliable model that can be used to estimate the electronic properties (i.e., the HOMO, LUMO, and band gap energies) of conjugated polymers would be a great tool for applications in organic electronics such as light‐emitting diodes, field‐effect transistors, and photovoltaic cells. Recently, poly(2,7‐carbazole) derivatives have shown promising results when used as an active donor layer in bulk heterojunction photovoltaic cells with power conversion efficiency exceeding 7%. By using a simple correlation between density functional theory (DFT) theoretical calculations performed on six model compounds (using the repeating unit) and experimental data from the six corresponding polymers, an accurate estimation of the HOMO energy level, the LUMO energy levels, and the band gap of several poly(2,7‐carbazole) derivatives was obtained. According to the theoretical data obtained for more than one hundred repeating units, fourteen new copolymers that can be used as p‐type materials in bulk heterojunction solar cells were selected and synthesized. Experimental data obtained from these materials were then used to refine the correlation between DFT and experimental data of poly(2,7‐carbazole) derivatives.

     

固相萃取-高效液相色谱法同时测定食品塑料包装材料中9种光稳定剂

建立了同时测定食品塑料包装材料中9种紫外光稳定剂含量的高效液相色谱方法。样品用甲醇-乙酸乙酯混合溶剂超声提取,经固相萃取小柱净化后,以ZORBAX SB-C18柱(250 mm×4.6 mm, 5 μm)为分离色谱柱,甲醇和水为流动相,梯度洗脱,以310 nm为检测波长进行定性、定量分析。该方法前处理简单、易操作,9种紫外光稳定剂分离效果良好。9种紫外光稳定剂在0.2～10 mg/L范围内呈良好的线性关系,线性相关系数大于0.999;方法检出限为0.05～0.1 mg/L;实际样品中的加标回收率为70.2%～89.0%,相对标准偏差为0.4%～4.5%。该方法简单、准确,能够满足食品塑料包装材料中紫外光稳定剂的检测要求。     

Study of migration of active components of phosphorescent oxygen sensors for food packaging applications

A study of migration of the active components of oxygen sensors into food is presented. Six types of sensors, based on different oxygen sensitive dyes (two metalloporphyrins and one ruthenium dye), polymers (polystyrene and polysulfone) and support materials, were exposed to a number of standard ‘food simulants’ recommended by FDA/EU guidelines and then assayed for migration or sensor components and changes in oxygen calibration. Both metalloporphyrin sensor dyes leached only in olive oil and in 95% ethanol (used as a positive control), at maximum levels of 19.22 μg/dm² for PtOEPK and 113.96 μg/dm² for PtTFPP. The RuDPP dye showed maximum leaching in 95% ethanol (25.19 μg/dm²) while also migrating in an acidic aqueous simulant. Planar supports such as polyester tended to enhance the stability of the sensor. Migration of the styrene monomer from the polystyrene encapsulation medium was concluded to be low enough to be insignificant. Migration of sensor components was shown to correlate with the changes in sensor response to oxygen. Based on these results, sensor combinations were ranked on the basis of their resistance to leaching and their general stability, safety and suitability for use on a large scale in packaged foods and related food applications was proven.     

聚苯乙烯提取物的检测与评价

随着材料科学的迅速发展,聚合物材料以不同的形态越来越广泛地应用于食品包装中。但是由于聚合物材料自身的特性及其改性加工,导致了很多低分子量化合物的形成,因而给食品安全性带来很大隐患,也危害着人们的身体健康。为了解决这一问题,在选用材料前,必须分析聚合物材料中低分子化合物的迁移情况,考虑迁移过程对包材使用的影响。实验中选用正庚烷、8%乙醇、50%乙醇和蒸馏水作为食品模拟液,用气相色谱测定聚苯乙烯提取物的迁移量,进而将实验数据分析比较。结果显示,迁移量随着温度的升高和时间的延长而不断增加,溶剂种类的影响为:正庚烷>50%乙醇>8%乙醇>蒸馏水。     

The Chemistry of Cyborgs—Interfacing Technical Devices with Organisms

The term “cyborg” refers to a cybernetic organism, which characterizes the chimera of a living organism and a machine. Owing to the widespread application of intracorporeal medical devices, cyborgs are no longer exclusively a subject of science fiction novels, but technically they already exist in our society. In this review, we briefly summarize the development of modern prosthetics and the evolution of brain–machine interfaces, and discuss the latest technical developments of implantable devices, in particular, biocompatible integrated electronics and microfluidics used for communication and control of living organisms. Recent examples of animal cyborgs and their relevance to fundamental and applied biomedical research and bioethics in this novel and exciting field at the crossroads of chemistry, biomedicine, and the engineering sciences are presented.