Explore the vast range of titles available.

In the present work, we prepare Cellulose Nanofibers Films (CNFs) incorporating silver nanostructures (Ag/AgCl nanocubes) in a ratio of 1–20 wt% to the organic matrix. We found that with the increase of Ag wt%, a raise in crystalline species corresponding to Ag/AgCl was observed. The diffraction pattern in 2Ө = 44.7° planes belonging to Ag (2 0 0) shifts to 2Ө = 45.45° with planes AgCl (2 2 0), due to the increase of Ag. Furthermore, we describe that incrementation in silver concentration aid in fibers gaining a higher arrangement. Scanning Electron Microscopy (SEM) images showed cubic structures formed by smaller cubic nanostructures. Electrochemical Impedance tests determined electrical resistance of the films, obtaining values of 551 Ω cm2, 62.6 Ω cm2, 3.78 Ω cm2, 7.9 Ω cm2, and 15.8 Ω cm2 for concentrations of 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% respectively; in addition to obtaining the CPE from films, demonstrating that they possess electrical conduction and energy storage capabilities.Graphic abstract

The current global warming is driving the use of clean and renewable energy. Intermittence is a drawback of clean energy. Energy storage is the answer to intermittence. Flow batteries, batteries, capacitors, and supercapacitors are among the most used energy storage devices in the world. In this paper, capacitors made from graphite and commercial graphene were fabricated. The obtained specific capacitances reached 851 F g −1 , indicating that the devices meet the performance standard for supercapacitors. The devices were fabricated using cellulose nanocrystals as binding material in the electrode, thus using an environmentally friendly binding material. Cyclic voltammetry revealed a quasi‐rectangular process. Charge–discharge cycles revealed a storage mechanism of electrical double layer. The Warburg impedance indicates the diffusive impedance of electrolyte ions in the devices.

Sargassum has become an “ecological disaster” on most beaches in the Caribbean Sea, causing serious health, safety, economic and environmental problems. The objective of this study was to valorize sargassum for the extraction of sodium alginate, cellulose and cellulose nanocrystals. Cellulose was also used in the manufacture of a separator for an energy storage device (ESD) based on expanded graphite and activated carbon. Sargassum was characterized physicochemically; the results of this characterization are very relevant for the generation of bioenergy and removal of toxic contaminants. The extracted materials were identified by FT-IR; the spectra were very similar to the IR spectra of commercial samples, which corroborated that the materials extracted were sodium alginate, cellulose and cellulose nanocrystals. The performance of the ESD/cellulose-based separator was determined using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Additionally, an RC circuit and an oscilloscope were used to perform a charge/discharge test. The voltammograms obtained for the ESD showed a rectangular shape with redox peaks characteristic of a pseudocapacitor and a battery, and the Nyquist plot showed a typical electrochemical performance of such ESD. Likewise, the developed devices have the capacity to store and release energy in seconds.

Purpose This paper aims to study the corrosion protection of 410 stainless steel (410SS) cracked by fatigue tests. The purpose of this study is to show that using polymeric coatings, it is possible to reduce the corrosion rate in metallic structures in operation. Design/methodology/approach Poly(3-hexylthiophene) (P3HT)/poly(methyl-methacrylate) (PMMA) composite was used as a coating to protect the cracked 410SS in the corrosive environment 0.5 M NaCl at 25°C and 80°C. Physicochemical characterization was carried out by adhesion tests, thermogravimetric analysis, nuclear magnetic resonance and size exclusion chromatography. Surface morphology was studied before and after the electrochemical tests by scanning electron microscopy. Uncoated and coated cracked 410SS were characterized by DC electrochemical techniques: linear polarization resistance and potentiodynamic polarization curves. Findings P3HT/PMMA coating reduced corrosion rate and crack propagation of 410SS in the corrosive medium NaCl 0.5M. The P3HT/PMMA coating increased the polarization resistance by one order of magnitude and decreased the corrosion current density by one order of magnitude, relative to the values obtained with uncoated cracked 410SS. The coating helped to have a less damaged surface and less crack propagation on the cracked 410SS. The feasibility of increasing the useful life of cracked metal structures in a saline environment was demonstrated through polymeric composite coatings. Originality/value In the literature, no works were detected that report the use of organic coatings to protect cracked metals against corrosion. This is the first reported work on the corrosion protection of 410SS in a saline medium using coatings based on P3HT/PMMA.

Cellulose nanocrystals (CNCs) are a very versatile material, and optimizing the reaction conditions to obtain them is vital for cost savings, purity, selectivity, or performance. In this study, the reaction conditions of the CNCs were tested, as well as their application as binders for the fabrication of electrodes of a symmetric capacitor (based on activated carbon). The resulting CNCs were physicochemically characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, atomic force microscopy, and its capacitive properties using cyclic voltammetry (CV). It was found that the best reaction conditions were at 45°C, 30 and 45 minutes, and 64 wt%. The CNCs were used as a binder, as they conferred stability to the electrodes and prevented the crumbling of the activated carbon electrodes. The CV measurements showed a capacitor behavior; CNCs can be used in energy storage applications.

The rise for innovation in the electrical industry is strongly driven by development of new materials. Features of new materials are changing design paradigms for engineers. In this paper, the electrical properties of films of cellulose nanocrystals were measured. It was found that humidity affects the dielectric strength on the cellulose nanocrystals (CNCs). The dielectric strength was similar to the value of the industrial dielectric paper. The addition of plasticizer improved the flexibility of the material but lowered the dielectric strength. The films of CNC had an ordered arrangement, as suggested by the iridescence shown by them. The humidity content of the films was measured by thermogravimetric analysis. The CNC film was used for assembling a capacitor and compared to a capacitor assembled with dielectric paper.

Purpose – The purpose of this paper is to study the effect of thermal treatment on the corrosion protection of steel by using poly(3-hexylthiophene) (P3HT) and P3HT/PS(polystyrene) or P3HT/PMMA(polymethyl methacrylate) blends coatings in sulfuric acid solution. Design/methodology/approach – The polymer coatings were thermally treated at two different temperatures (100 and 200°C, respectively) and were compared with the polymer coatings dried at room temperature in their application as protective coatings against corrosion of A36 steel. The corrosion resistance of polymer coatings-covered steel substrates was evaluated by using potentiodynamic polarization curves and linear polarization resistance. Findings – At 25 and 100°C, polymer coatings showed a better protection of the A36 steel, and the corrosion rate diminished in three orders of magnitude with regard to the bare steel. Morphological study showed that the increased temperature benefited the integration of the two polymeric phases; however; the temperature of 200°C affected the film quality, generated cracks and holes, which affected the barrier properties of the coatings. Research limitations/implications – The research involved the synthesis and physicochemical characterization of the polymeric coatings (P3HT, PS/P3HT y PMMA/P3HT), as well as their application as coatings in the steel to prevent corrosion. The effect of thermal treatment of the protective coatings on steel corrosion was studied. Practical implications – This paper aims to contribute to reducing the problem of metal corrosion through the use of polymer coatings. Social implications – Today, majority of metal surfaces are subject under the protection to prevent a very common phenomenon, that is corrosion. Corrosion is the result of chemical reactions that occur between a metal or a metal alloy and its environment. Corrosion creates a degradation of the material that has an impact on some economic, environmental and even social aspects, here the great importance of its protection. Originality/value – It is shown in this study that the P3HT coating provides better corrosion protection of the A36 steel than the PS and PMMA coatings. However, mixtures of P3HT with PMMA and PS protected the steel from corrosion by two and three orders of magnitude similar to the simple P3HT coating. Polymer blends improved adhesion to the substrate and mechanical property of the coating, and in addition, the polymer blends made cheaper coating.

An electrochemically deposited poly3-methylthiophene (P3MT) thin film has been used as the primary electrochromic element in a solid two-electrode electrochromic device (ECD) with a viscous polymeric electrolyte (PE) of polymethyl methacrylate and lithium perchlorate co-dissolved in ethylene and propylene carbonates. The counter-electrode of the ECD was a transparent conductive (indium-tin oxide, ITO) glass (single ECD) or a polyaniline (PANI)-coated ITO glass (dual ECD). Dual P3MT-PANI-based ECDs exhibit a lower optical switch potential (less than 0.5 V) and a faster color change speed (around 1 s) compared with the single devices, independent on the lithium salt concentration and the viscosity of the polymeric electrolyte. Electrochemical impedance spectra of both types of ECDs were analyzed at zero bias. It indicates that the use of the secondary electroactive element leads to a lower counter-ion diffusion resistance as well as to a larger counter-ion storage capacity in the electrochromic element/polymeric electrolyte interfaces. Consequently, the oxidation–reduction potential is lower, and the charge transfer process is faster in the dual devices than those in the single ones.

Background Maternal vaccines can reduce the burden of diseases for both mother and neonate. The development and implementation of such vaccines require a thorough interpretation of safety data and standardized disease case definitions. This study aimed to evaluate the current rates for adverse pregnancy outcomes, maternal and neonatal events of interest (EOIs) that will be informative for preparing future phase III clinical trials on maternal vaccines conducted in low- and middle-income countries and further assisting in safety data interpretation (e.g., monitoring potential safety signals in clinical trials, and/or helping with the causality assessments of adverse events following immunization). Methods We performed a prospective cohort study on healthy 18–45-year-old women, with singleton, low-risk pregnancies, with a gestational age of ≥24 0/7 weeks at enrollment and ≤27 6/7 weeks at first visit, and their neonates. The study was conducted between 2019–2021 in 10 countries that were considered low- and middle-income countries by the World Bank Group at the time the study was designed. All pregnancy-related outcomes and maternal EOIs occurring from enrollment up to 42 days post-delivery and neonatal EOIs occurring within the first 28 days after birth were recorded. Results Of 2311 pregnant women and 2181 neonates enrolled, 2222 and 2094 were included in the analyses, respectively. Most livebirths (2088 [94.0%]) were without apparent congenital anomalies. Preterm delivery (166 [7.5%]), non-reassuring fetal status (137 [6.2%]), and hypertensive disorders of pregnancy (125 [5.6%]) were the most frequently reported EOIs related to pregnancy. The most frequent neonatal EOIs were low birthweight (including very low birthweight) (156 [7.4%]), preterm birth (141 [6.7%]), small for gestational age (111 [5.3%]), and congenital anomalies (103 [4.9%], including mainly major external structural defects, as well as detected internal and functional defects). Overall, there were similar frequencies in pregnancy outcomes, pregnancy-related and neonatal EOIs across countries, although some variation in the reporting rate was noted. Conclusion This multicountry study contributes to establishing the most recent background rates for pregnancy outcomes, maternal and neonatal EOIs in low- and middle-income regions. The clinical relevance in the context of the safety assessment in future trials will be applied. Trial registration NCT03614676 (03/08/2018).

Incidence data of respiratory syncytial virus-associated lower respiratory tract illness (RSV-LRTI) are sparse in low- and middle-income countries (LMICs). We estimated RSV-LRTI incidence rates (IRs) in infants in LMICs using World Health Organization case definitions. This prospective cohort study, conducted in 10 LMICs from May 2019 to October 2021 (largely overlapping with the coronavirus disease 2019 [COVID-19] pandemic), followed infants born to women with low-risk pregnancies for 1 year from birth using active and passive surveillance to detect potential LRTIs, and quantitative reverse-transcription polymerase chain reaction on nasal swabs to detect RSV. Among 2094 infants, 32 (1.5%) experienced an RSV-LRTI (8 during their first 6 months of life, 24 thereafter). Seventeen (0.8%) infants had severe RSV-LRTI and 168 (8.0%) had all-cause LRTI. IRs (95% confidence intervals [CIs]) of first RSV-LRTI episode were 1.0 (.3-2.3), 0.8 (.3-1.5), and 1.6 (1.1-2.2) per 100 person-years for infants aged 0-2, 0-5, and 0-11 months, respectively. IRs (95% CIs) of the first all-cause LRTI episode were 10.7 (8.1-14.0), 11.7 (9.6-14.0), and 8.7 (7.5-10.2) per 100 person-years, respectively. IRs varied by country (RSV-LRTI: 0.0-8.3, all-cause LRTI: 0.0-49.6 per 100 person-years for 0- to 11-month-olds). RSV-LRTI IRs in infants in this study were relatively low, likely due to reduced viral circulation caused by COVID-19-related nonpharmaceutical interventions. NCT03614676.