Association equlibria in acetonitrile solution of tetracyanoquinodimethanides

Trimetric ion (TCNQ)^2?₃ has been discovered in mixed solutions of TCNQ and LiTCNQ in acetonitrile. The estimated association constant isK_T = 5.6 × 10¹⁰ øl² mol^?2.     

On a quest of reverse translation

Explaining the emergence of life is perhaps central and the most challenging question in modern science. Within this area of research, the emergence and evolution of the genetic code is supposed to be a critical transition in the evolution of modern organisms. The canonical genetic code is one of the most dominant aspects of life on this planet, and thus studying its origin is critical to understanding the evolution of life, including life’s emergence. In this sense it is possible to view the ribosome as a digital-to-analogue information converter. Why the translation apparatus evolved, is one of the enduring mysteries of molecular biology. Assuming the hypothesis that during the emergence of life evolution had to first involve autocatalytic systems, which only subsequently acquired the capacity of genetic heredity, in the present article we discuss some aspects and causes of the possible emergence of digital, discrete information arising from analogue information realized in the intra- and inter-molecular interactions throughout molecular evolution. How such reverse translation was achieved at a molecular level is still unclear. The results of such debates and investigations might shift current biological paradigms and might also have a momentous significance for modern philosophy in understanding our place in the universe.     

Electrosynthesis,characterization and photoconducting performance of copolymer poly(terthiophene + sexithiophene + TiO<Subscript>2</Subscript>)/ITO composite material

In the present work, a new composite material poly(3T + 6T + TiO₂) was electrochemically synthesized. This composite material was synthesized in a solution of (CH2Cl2/TBAP) containing the monomers (terthiophene), (sexithiophene) and semiconductor (TiO₂) particles. The preparedsamples were characterized electrochemically by cyclic voltamperometry (CV) and spectrometry analysis by scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) absorption spectroscopy, energy dispersive X-ray spectroscopy (EDX) and fourier transform infrared spectroscopy (FTIR), respectively. The effect of TiO₂ concentration in the solution on dispersed microparticle entity and on the photocurrent response was investigated. The results showed that TiO₂ particles were dispersed and codeposited into the copolymer poly(3T + 6T + TiO₂) matrix, and titanium atom was confirmed by EDX spectra. From SEM images, the TiO₂ has a spherical shape and micrometer size. The FTIR spectrum indicated that titanium dioxide do not show a significant modification in terms of band shape and no interaction between polymers and TiO₂ particles. Furthermore, the results showed that the composite films with different amounts of TiO₂ exhibit good photocurrent properties which imply that these composites films can be used in various fields, such as photoelectrochemical applications as photovoltaic cells.     

光响应超分子聚合物

超分子聚合物是超分子化学、高分子化学和材料化学领域的研究热点.将光响应的功能基团以非共价作用构筑到超分子聚合物体系中,得到光响应型超分子聚合物,从而能够将超分子聚合物的独特性质与光化学反应的优势有效地结合起来,从而构筑新型的光功能材料.本文总结了近年来本课题组有关光响应超分子聚合物方面的研究工作:介绍了主链型的光响应超分子聚合物的光调控组装和解离,超分子聚合物和共价聚合物的光控可逆切换和光调控组装形貌;另外还举例介绍了具有自修复和室温磷光发射等功能的侧链型光响应超分子聚合物,并对刺激-响应的超分子聚合物领域的发展做了展望.     

弹道明胶老化初级阶段的模型

用流变震荡模式研究了10 wt%浓度的弹道明胶在冷却和等温下的老化行为.对明胶从sol-gel点冷却到某个目标温度的过程,通过不同冷却速率的实验,建了一个弹性模量与温度的线性关系.不同温度下明胶的等温老化实验表明,弹性模量-时间曲线具有相似的形状.依据Normand提出的二级反应动力学模型,引入一个表征明胶老化行为的速率常数,构建了一个预测弹道明胶在老化初级阶段的弹性模量演化的模型.该模型中模量-温度关系在初始和无穷大时是直线,其他模量-温度线是近似直线,并交于sol-gel点.老化速率常数和过冷度之间符合Flory-Weaver方程.对弹性模量和老化时间进行归一化处理,可将不同温度下的老化曲线叠加成一条主曲线.     

Simple and rapid synthesis of ternary polyaniline/titanium oxide/graphene by simultaneous TiO<Subscript>2</Subscript> generation and aniline oxidation as hybrid materials for supercapacitor applications

This paper reports a simple methodology for the synthesis of a polyaniline/titanium oxide/graphene hybrid (Pani/TiO₂/GN) using a simple methodology, and their application as a supercapacitor electrode material for energy storage. The Pani/TiO₂/GN hybrid was prepared by a simple approach by simultaneous generation of Pani and TiO₂ in situ from aniline and titanium iso-propoxide, respectively, in the presence of GN under ice bath conditions. The incorporation of GN improved the electrical conductivity of Pani and helped to decrease the charge transfer resistance, whereas TiO₂ generation by an in situ method increased the surface area considerably and enhanced the capacitance of the Pani/TiO₂/GN hybrid. TEM showed that Pani and TiO₂ were well incorporated and coated on the GN successfully. The shift of the peaks in the FTIR spectrum and XRD pattern of the Pani/TiO₂/GN hybrid compared to their pure counterparts suggested that TiO₂ and Pani had been perfectly coated on the GN, and there was a strong interaction among Pani, GN, and TiO₂ particles. The electrochemical performance of the as-prepared Pani/TiO₂/GN hybrid electrode showed a high specific capacitance of 403.2 F g^?1 at a current density of 2 A g^?1 and excellent cycling stability for up to 1000 cycles. This suggested that the effective incorporation of GN and TiO₂ into Pani and the high surface area could simultaneously increase the electrochemical capacitance and cyclic stability of the Pani/TiO₂/GN hybrid, leading to superior electrochemical performance.

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Graphical abstract The electrochemical performance of as-prepared Pani/TiO₂/GN hybrid electrode showed a high specific capacitance of 403.2 F g^?-1 at a current density of 2 A g^?-1 and excellent cycling stability for up to 1000 cycles. This suggested that the effective incorporation of GN and TiO₂ into Pani and the high surface area could simultaneously increase the electrochemical capacitance and cycle stability of the Pani/TiO₂/GN hybrid, leading to superior electrochemical performance.

     

Aleksandr Georgievich Tyurin (1953–2015) and his research in corrosion science

This paper is a tribute to one of the leading Russian scientists in the field of corrosion science and my supervisor, Aleksandr Georgievich Tyurin, who suddenly and unexpectedly passed away in 2015. A short biographical note is given together with an outline of his contributions to corrosion and electrochemical science.     

Lithium intercalation into disordered carbon/SiCN composite. Part 2: Raman spectroscopy and <Superscript>7</Superscript>Li MAS NMR investigation of lithium storage sites

Within this work, we analyze the lithium storage sites within carbon/silicon carbonitride (SiCN) composites. Commercial carbons, HD3 (hard carbon) and LD1N and LD2N (soft carbons), of varying porosity are impregnated with polysilazane (HTT 1800) and pyrolysed at 1100 °C. It is found in the first part of this study (Graczyk-Zajac et al. J Solid State Electrochem 19:2763–2769, 2015) that the initial porosity of the carbon phase plays an important role in determining the lithium insertion capacity and rate capability of the composite material. By applying Raman spectroscopy and solid-state ⁷Li MAS NMR on pristine, lithiated, and delithiated samples, we investigate the lithium storage sites within the composite materials. By means of Raman spectroscopy, it has been found that lithium storage in hard carbon-derived composites occurs in a significant extent via adsorption-like process within unorganized carbon, whereas for the soft carbon composites, storage in turbostratic carbon is identified. ⁷Li solid-state NMR confirms these findings revealing that more than 33 % of lithium stored in HD3/SiCN is adsorbed in ionic form at the surface and in pores of the composite, while around 38 % is stored between carbon layers. LD1N and LD2N composites store more than 50 % of lithium in the intercalation-type sites.