A closer look at the polyacrylamide fibers for natural-like artificial muscle fabrication

International audienc

Electrochemical properties and actuation mechanisms of polyacrylamide hydrogel for artificial muscle application

International audienceThis paper presents a comprehensive study of the electromechanical behavior of PAAM hydrogel actuators. In this study, we developed a new method for the characterization of the pH gradient inside the gel actuator. Then we analyzed the volume variation kinetics of the gel responding to various pH stimulations and investigated the electroactivity of PAAM actuators in a fully hydrated gel. Finally we explain the bending mechanism of the hydrogel actuator based on the phenomenon of diffusion of hydroxide and hydronium ions showing the correlation between the electrical, chemical and mechanical properties of such devices

Controlling the Stiffness and Porosity of Polyacrylamide Hydrogel Matrices and Evaluating their Effect on Podocyte-Behavior

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Dye-Sensitized Solar Cells Based on a Natural Low Cost Halochromic Sensitizer

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Electrochemical and electromechanical properties of fully hydrolyzed polyacrylamide for applications in biomimetics

International audienceThis paper focuses on the development of fully hydrolyzed polyacrylamide (PAAM) hydrogel for applications in biomimetics. We present an analysis of the motion of actuators based on PAAM hydrogel in order to obtain the elementary background needed for the design of actuating devices based on this material, which has a high compatibility with living tissues. The gel properties are investigated, the electroactivity of the hydrogel is shown and a qualitative-quantitative study demonstrating the basics of motion of such actuators is presented

Two-step formation mechanism of Acetobacter cellulosic biofilm: synthesis of sparse and compact cellulose

International audienceClassical studies concerning “Acetobacter xylinum” focus on bacterial cellulose “BC” yield and rate in broth, after a long period of incubation (7–14 days). Such observations do not highlight bacterial physiology in the first incubation hours and its impact on BC production. In this study, the growth of a wild strain of Acetobacter was monitored in the first incubation hours. We showed the presence of two different physiologies; the first extends from the incubation moment till the formation of a sparse BC. Sparse BC modifies surface viscosity, and stabilizes hydrodynamic conditions to initiate compact BC production that marks the second physiology. Two containers, of different shapes, were used to confirm our findings, one of which is a culture tube with high drift currents on the broth-air interface, and the other is a conical flask with more stable hydrodynamic conditions at the culture’s surface. We showed that Acetobacter always follows two physiologies independent of the container shape. Logistic model, FTIR, XRD and SEM analysis are used to confirm the results

Culture medium pH influence on Gluconacetobacter physiology: Cellulose production rate and yield enhancement in presence of multiple carbon sources

International audienceGluconacetobacter genera are valued for bacterial cellulose (BC) and acetic acid production. BC is produced at optimal yields in classical microbiological media that are expensive for a large scale of production. In addition, BC usage for industrial purposes is limited due to low conversion rate into cellulose and to long incubation duration.In this paper, Gluconacetobacter isolated from apple vinegar was kinetically studied to evaluate cellulose production in presence of different carbon sources. Acetic and citric acid effect on Gluconacetobacter metabolism is clarified. It was shown that Gluconacetobacter uses glucose as a primary carbon source for cells growth and products formation. Acetic acid employment as a co-carbon source in Hestrin Schramm medium showed an increase of 17% in BC yield with a moderate decrease in the crystallite size of the resulting polymer

Polyaniline–titania solid electrolyte for new generation photovoltaic single-layer devices

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Formation mechanism of polyaniline self-assembled needles and urchin-like structures assisted by magnesium oxide

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