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With the expansion of demand for non-renewable energy including fossil fuels, the threatening effects coming along with this have increased at a fast-paced rate and it is necessary to build a sustainable environment by using renewable energy sources. However, the limited available natural resources, extensive use of existing ones have led to a necessity of storing energy for further future purposes. As a result, electrochemical energy storage (EES) devices are invented as a viable candidate to overcome this issue in an eco-friendly manner. Herein, this study is aimed to develop a high-performance supercapacitor using polyaniline (PANI). The low electrochemical window and energy storage capacity of polyaniline was improved by carbonization and activation with KOH. Different ratio of polyaniline and KOH was used to tune the surface area of carbonized polyaniline. The surface area and porosity were significantly improved after activation of the polyaniline. Supercapacitor devices were fabricated using activated polyaniline as electrode material in various electrolytes such as aqueous, organic, and ionic liquid. The devices showed high electrochemical performance with high cyclic stability and coulombic efficiency. Our research suggests that the carbonization of polyaniline introduces nitrogen doping and significantly improves its electrochemical properties for high-performance energy storage devices.

Nitrogen-doped high-performance carbon using polyaniline for high-capacitance electrochemical energy storage devices

As a renewable source, biodegradable polyols have had a significant impact on the development of the polyurethane foam (PUF) industry. In this study, the interest in using castor oil-based polyol as a polyol was due to its inedibility, low cost, presence of hydroxyl groups, and carbon-carbon double bonding. Firstly, castor oil was modified by converting double bonds into hydroxyl groups to increase its functionality towards isocyanate. Modified castor polyol showed a high hydroxyl number (260-280 mg KOH/g), making it convenient for form PUFs. Flame retardant (FR) has been introduced in the manufacture of polyurethane foam to reduce flammability. Bio-based rigid PUFs were prepared by a one-shot free-forming process with isocyanate in the presence of blowing agent, catalyst, surfactant, and additive flame retardant. Melamine cyanurate (MC), a nitrogen-based FR, and expandable graphite (EG), a carbon-based FR, were (separately) introduced to suppress flame during RPUF combustion. The properties of RPUFs were characterized using FT-IR, scanning electron microscopy, apparent density, compression test, thermogravimetry analysis (TGA), and horizontal burning test. Simultaneously, the impact of FR concentration on RPUF properties was also investigated. All the RPUFs showed a closed-cell structure (over 90%) with a density of around 40 kg/m3 and high mechanical strength. When FR was incorporated, RPUFs presented a drastic decrease in burning time and weight loss. This result suggests that castor oil-based RPUFs can be used for potential applications in thermal insulation. The weight loss curve in TGA showed a two-step thermal decomposition behavior, and the difference in flame retardant activity of MC and EG in RPUFs can be explained by a difference in the weight loss and residue analysis. Therefore, this work provides a simplistic route to synthesize RPUFs from bio-based polyol with persistent flame retardancy and excellent mechanical properties.

Sustainable approach to reducing the flammability and improving thermomechanical properties of castor oil-based rigid polyurethane foam

Evaluating the adhesion of a surface gives us, somehow, a sensorial (touch-like) glimpse of the fascinating world of molecular interactions. This presentation will provide a brief review of several years of research in the field of Surface Forces and Interactions. Fundamental studies trying, for example to understand the relationship between adhesion and friction using thin polymer films as well as more applied studies (in cosmetics, dermatology and tactile perception) will be the object of a critical perspective analysis. Hair and Skin are biological surfaces that are the target of many personal care products whose ultimate performance is strongly linked to the way the ingredients attach or interact to it. Topics that will be included are the following: the influence of endogenous lipids (fatty acids, ceramides, etc.) on skin’s contact angle and adhesion, the effect of humidity on the interaction between natural fibers and its ultimate manageability, the mechanisms by which cell adhesion critically affects skin (stratum corneum) desquamation, the impact of the structure of thin films of polyelectrolytes and surfactants on the lubricating effects of shampoos, the influence of surface patterning in the adhesion, sensorial (touch) perception of biomimetic coatings and the way pollutant particles adhere to skin. Finally, in this field of study the name Kash Mittal has accompanied me at the same pace as my knowledge has increased in this fascinating area of adhesion research. The broad effort of Dr Mittal’s implication on the topic, either via editing journals or writing books, has made it possible to approach and connect researchers from many different areas, making adhesion a fully interdisciplinary topic.

Towards controlling the way surfaces interact and adhere. From Polymers to Biophysical cosmetic and dermatological applications

In our ongoing research of previously synthesized and investigated monosubstituted bench stable 3,3-difluorocyclopropenes as the reagents in different reactions of the MedChem relevant building blocks formation, we reported [3+2] cycloaddition of a diazo acetic ester and gem-difluorocyclopropenes. The number of gem-difluorocyclopropenes with aliphatic substituents were examined in the reaction above to form functionalized [1,2]-pyridazines. The reaction conditions were optimized. The optimized conditions reduce the reaction time compared to the published literature analogies and simplify the procedure for the isolation and purification of target compounds. In the course of investigation of the reaction scope and limitations, it was found that it is tolerant to hydroxyl and protected amino groups. The synthesis of derivatives with a side chain R = CH2CH2OH and CH2CH2NH2 was carried out, significantly expanding the corresponding pyridazines' functionalization. All these results allow us to significantly expand the reaction scope to the functionalized chemical space as well as small aliphatic substituted examples (Table 1). Based on the obtained polyfunctional pyridazines, an approach to previously unknown bicyclic pyridazines with fused heteroaliphatic cycles was developed in multigram amounts, which are potentially important blocks for medicinal chemistry. The possibility of further modification of obtained pyridazines is also shown (Table 2).

Bench-stable 3,3-difluorocyclopropenes in [3+2] cycloaddition reaction with diazo acetic ester

In our ongoing research of previously synthesized and investigated α-Amino acids derived diazoketones (AADDK) as the MedChem relevant building blocks formation, we are reporting about their utilizing as haloketone's surrogates. Here we demonstrate their use in the formation of thiazoles via [3+2]-heterocyclization reaction with thioamides. The optimal conditions are elaborated. The stereoselectivity of the reaction is maintained. The tolerance of the procedure for different protecting groups is shown. The scope of the reaction was significantly increased to the AADDK-substrates, for which appropriate haloketones are unstable and/or unknown (Scheme 1). The limitations and advantages of the method compared to classic haloketone's cyclization are discussed.

α-Amino acids derived diazoketones (AADDK) as synthons for thiazoles synthesis

In our recent research, the efficient replacement of expensive Au-based catalyst in the reaction ketones with propargylamine to Cu-based one was elaborated. In our further optimization of this process, we tried to discover Cu-based composite material for further use in flow reactors. The aim of this study was to evaluate the catalytic properties of a series of Cu-containing heterogeneous composites in the synthesis of fused pyridines from propargylamine and cycloalkanones. The Cu-composites was obtained by pyrolysis of copper(II) 1,10-phenantrolinate or copper(II) 1,2-diaminobenzene complexes deposited on SiO2. The copper content and conditions of pyrolysis, such as temperature and heating rate, were varied. It was found that the sample obtained as a result of pyrolysis of copper(II) 1,2-diaminobenzene deposited on SiO2 during 20 min at 400 °C was most active, leading to more than 60 % yield of the ethyl-5,6,7,8-tetrahydroquinoline-6-carboxylate after 3.5 h of the reaction (Figure 1). An increase of the pyrolysis temperature to 600 °C led to the formation of samples that had lower catalytically activity. Generally, samples obtained as a result of pyrolysis of Cu(II) complexes with 1,2-diaminobenzene had higher catalytic activity in the reaction compared to the samples formed using 1,10-phenanthroline complexes. An increase of copper content in the precursors of the composite from 5% to 14% has almost no effect on the catalytic activity of the final composites. The possibility of using obtained composite will also be discussed.

American Chemical Society

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