Electrospinning and Post-Spun Chain Conformations of Synthetic, Hydrophobic Poly(α-amino acid)s.

Electrospinning and post-spun conformations of hydrophobic poly(α-amino acid)s are described in this study. The poly(α-amino acid)s, poly(Gly), poly(L-Ala), poly(L-Val), and poly(L-Leu) were synthesized via corresponding N-carboxy-a-amino acid anhydrides. The average molecular weight and degree of polymerization of these polymers were determined by N-terminus labeling using 2,4-dinitrofluorobenzene and by viscometry in the case of poly(Gly). These poly(α-amino acid)s were electrospun from trifluoroacetic acid or trifluoroacetic acid/dichloromethane solutions. The FT-IR spectroscopy and wide-angle X-ray diffraction indicated that the electrospun poly(L-Ala) and poly(L-Leu) fibers predominantly adopts α-helical structure, whereas poly(L-Val) and poly(Gly) fibers exhibited mainly β-strand and random coil structures, respectively

Sustainable Electronics Based on Crop Plant Extracts and Graphene: A “Bioadvantaged” Approach

In today’s fast-paced and well-connected world, consumer electronics are evolving rapidly. As a result, the amount of discarded electronic devices is becoming a major health and environmental concern. The rapid expansion of flexible electronics has the potential to transform consumer electronic devices from rigid phones and tablets to robust wearable devices. This means increased use of plastics in consumer electronics and the potential to generate more persistent plastic waste for the environment. Hence, today, the need for flexible biodegradable electronics is at the forefront of minimizing the mounting pile of global electronic waste. A “bioadvantaged” approach to develop a biodegradable, flexible, and application-adaptable electronic components based on crop components and graphene is reported. More specifically, by combining zein, a corn-derived protein, and aleuritic acid, a major monomer of tomato cuticles and sheellac, along with graphene, biocomposite conductors having low electrical resistance (≈10 Ω sq−1) with exceptional mechanical and fatigue resilience are fabricated. Further, a number of high-performance electronic applications, such as THz electromagnetic shielding, flexible GHz antenna construction, and flexible solar cell electrode, are demonstrated. Excellent performance results are measured from each application comparable to conventional nondegrading counterparts, thus paving the way for the concept of “plant-e-tronics” towards sustainability

Blend electrospinning of dye-functionalized chitosan and poly(ε-caprolactone) : towards biocompatible pH-sensors

Fast-response and easy-to-visualize colorimetric nanofibrous sensors show great potential for visual and continuous control of external stimuli. This makes them applicable in many fields, including wound management, where nanofibers serve as an optimal support material. In this paper, fast responding and user-friendly biocompatible, halochromic nanofibrous sensors are successfully fabricated by incorporating the halochromic dyes Methyl Red and Rose Bengal inside a chitosan/poly(e-caprolactone) nanofibrous matrix. The commonly applied dye-doping technique frequently suffers from dye-leaching, which not only reduces the sensor's sensitivity over time but can also induce adverse effects. Therefore, in this work, dye-immobilization is accomplished by covalent dye-modification of chitosan before blend electrospinning. It is shown that efficient dye-immobilization with minimal dye-leaching is achieved within the biomedical relevant pH-region, without significantly affecting the halochromic behavior of the dyes. This is in contrast to the commonly applied dye-doping technique and other dye-immobilization strategies stated in literature. Moreover, the nanofibers show high and reproducible pH-sensitivity by providing an instantaneous color change in response to change in pH in aqueous medium and when exposed to acidic or basic gases. The results stated within this work are of particular interest for natural (bio) polymers for which covalent modification combined with electrospinning provides a universal method for versatile dye-functionalization of large area nanofibrous membranes with proper dye-immobilization

STUDIES ON THE INHIBITIVE EFFECT OF 3-HYDROXYFLAVONE ON THE ACID CORROSION OF MILD STEEL

The corrosion inhibition effect of 3-hydroxyflavone was studied on mild steel in 1 M hydrochloric acid (HCl). The anticorrosive effect was evaluated by weight loss and electrochemical methods which include Tafel polarization and AC impedance studies at 300 K. In weight loss method, the inhibition efficiency increased with increase in inhibitor concentration, and decreased with increase in temperature and immersion time, and acid concentration. The inhibitor showed maximum efficiency of 91% at 4 × 10-4 M concentration in 1 M hydrochloric acid. The Tafel polarization study showed that the inhibitor behaves likely as cathodic type. The corrosion inhibition effect measured by weight loss method and electrochemical studies was in good agreement with each other. The surface analysis was done by using scanning electron microscope (SEM). Several adsorption isotherms are assessed to study the adsorption behavior of the inhibitor on the mild steel surface. The negative value of ΔGads indicates the spontaneous adsorption of the inhibitor on mild steel surface.Adsorption isotherm, corrosion inhibition, electrochemical studies, 3-hydroxyflavone

Electrospinning and Post-Spun Chain Conformations of Synthetic, Hydrophobic Poly(α-amino acid)s

Electrospinning and post-spun conformations of hydrophobic poly(α-amino acid)s are described in this study. The poly(α-amino acid)s, poly(Gly), poly(l-Ala), poly(l-Val), and poly(l-Leu) were synthesized via corresponding N-carboxy-α-amino acid anhydrides. The average molecular weight and degree of polymerization of these polymers were determined by N-terminus labeling using 2,4-dinitrofluorobenzene and by viscometry in the case of poly(Gly). These poly(α-amino acid)s were electrospun from trifluoroacetic acid or trifluoroacetic acid/dichloromethane solutions. The FT-IR spectroscopy and wide-angle X-ray diffraction indicated that the electrospun poly(l-Ala) and poly(l-Leu) fibers predominantly adopts α-helical structure, whereas poly(l-Val) and poly(Gly) fibers exhibited mainly β-strand and random coil structures, respectively

Facile Synthesis of Core/Shell-like NiCo2O4-Decorated MWCNTs and its Excellent Electrocatalytic Activity for Methanol Oxidation

Aulario en la Ciudad Universitaria. Madrid. Convocatoria Abril. Plan 1996. Proyecto fin de carrera. Universidad Politécnica de Madrid. Escuela Técnica Superior de Arquitectur

FT-IR spectroscopy of Ch and DMAB(P)-Ch.

<p>FT-IR spectroscopy of Ch and DMAB(P)-Ch.</p

Ruthenium(II) 9,10-phenanthrenequinone thiosemicarbazone complexes: synthesis, characterization, and catalytic activity towards the reduction as well as condensation of nitriles

<div><p>The ligands 9,10-phenanthrenequinone-N⁴-substituted thiosemicarbazones (HL_1–3) and their ruthenium(II) complexes were synthesized and characterized by elemental and spectroscopic methods. The ligands are tridentate, monobasic chelating ligands with O, N, and S as the donor sites and are in the thiol form in all the complexes. Catalytic studies showed that all the complexes displayed good catalytic activity towards the reduction of nitriles and also the condensation of nitriles with 2-aminoalcohol under solvent-free conditions.</p></div