Natural and Eco-Friendly Materials for Triboelectric Energy Harvesting

Triboelectric nanogenerators (TENGs) are promising electric energy harvesting devices as they can produce renewable clean energy using mechanical excitations from the environment. Several designs of triboelectric energy harvesters relying on biocompatible and eco-friendly natural materials have been introduced in recent years. Their ability to provide customizable self-powering for a wide range of applications, including biomedical devices, pressure and chemical sensors, and battery charging appliances, has been demonstrated. This review summarizes major advances already achieved in the field of triboelectric energy harvesting using biocompatible and eco-friendly natural materials. A rigorous, comparative, and critical analysis of preparation and testing methods is also presented. Electric power up to 14 mW was already achieved for the dry leaf/polyvinylidene fluoride-based TENG devices. These findings highlight the potential of eco-friendly self-powering systems and demonstrate the unique properties of the plants to generate electric energy for multiple applications.[Figure not available: see fulltext.]. © 2020, © 2020, The Author(s).Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção, INCT-ENMinistry of Education and Science of the Russian Federation, MinobrnaukaFundação para a Ciência e a Tecnologia, FCT: SFRH/BPD/117475/2016, CENTRO-01-0145-FEDER-031679, POCI-01-0145-FEDER-031132This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC. S.K. and A.K. were partly supported by FCT (Portugal) through the project “BioPiezo”- PTDC/CTM–CTM/31679/2017 (CENTRO-01-0145-FEDER-031679). M. Soares dos Santos was also supported by FCT, through the grant reference SFRH/BPD/117475/2016. All authors were partly supported by FCT through the project “SelfMED” (POCI-01-0145-FEDER-031132). Part of this work was funded by national funds (OE), through FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. The research was also supported by the Ministry of Education and Science of the Russian Federation in the framework of the Increase Competitiveness Program of NUST « MISiS » (No. K2-2019-015)

Chemical solution deposition of BiFeO3 films with layer-by-layer control of the coverage and composition

Chemical solution deposition of BiFeO3 thin films is one of the most commercially available techniques to produce large-scale low-cost coatings for further application in memory devices. In this contribution, we implemented piezoresponse force and conductive atomic force microscopies to study the layer-by-layer sol-gel deposition of BiFeO3 thin films focusing on the local phase distribution, morphology, piezoelectric response, and leakage current. The final properties of resulting thin films are found to be determined not only by the composition of the gel and crystallization step but by the gelation step as well. The drying temperature and treatment duration of the solution are shown to drastically influence the film coverage, which finally determines the morphology of the films and behavior of the crystallization process. © 2020 by the authors.Russian Science Foundation, RSF: 19-72-10076The research was funded by Russian Science Foundation, grant number 19-72-10076. The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU was used

Water adsorption and polar properties of self-assembled diphenylalanine nanotubes

Experimental part of this work was performed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. Theoretical part of the work was supported by Russian Science Foundation (Grant No. 18-72-00052). S.K., P.Z. and A.K. are grateful to FCT project PTDC/CTM-CTM/31679/2017. P.Z. is grateful to FCT project PTDC/QEQ-QAN/6373/2014. S.K and A.K are grateful to joint Portugal-Turkey project (TUBITAK/0006/2014)

Inkjet printing of Sc-doped TiO\u3csub\u3e2\u3c/sub\u3e with enhanced photoactivity

\u3cp\u3eHere we report the methodology for nanocomposite fabrication based on the inkjet printing technique. Doped TiO\u3csub\u3e2\u3c/sub\u3e nanoparticles with Sc contents up to 10 wt.% were synthesized and adapted towards a facile fabrication of microscale structures and thin film printing. Implementation of the state-of-the-art low-temperature synthesis allowed to us successfully incorporate high concentrations of Sc\u3csup\u3e3+\u3c/sup\u3e ions into the TiO\u3csub\u3e2\u3c/sub\u3e lattice and improve the light absorption characteristics of the resulting materials. Without affecting the anatase structure substantially, Sc doping gave rise to an intensified absorbance capacity and provided the means for the efficient fabrication of Sc-TiO\u3csub\u3e2\u3c/sub\u3e microarchitectures via the inkjet printing technique. The changes in the spectral and structural characteristics of the Sc-TiO\u3csub\u3e2\u3c/sub\u3e composites were observed by Energy Dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-vis methods. The rheological parameters of the colloidal suspension based on the synthesized Sc-TiO\u3csub\u3e2\u3c/sub\u3e nanoparticles were adapted for inkjet printing in terms of the optimal viscosity, morphology, and surface tension. The developed individual ink characteristics allowed us to produce a close coherence between the enhanced optical properties of the Sc-TiO\u3csub\u3e2\u3c/sub\u3e prepared the sol-gel method and the inkjet-printed films. The introduced methodology features the possibility to inkjet-print doped and pure TiO\u3csub\u3e2\u3c/sub\u3e robust films for potential large-scale fabrication.\u3c/p\u3

Inkjet printing of Sc-Doped TiO₂ with enhanced photoactivity

Here we report the methodology for nanocomposite fabrication based on the inkjet printing technique. Doped TiO2 nanoparticles with Sc contents up to 10 wt.% were synthesized and adapted towards a facile fabrication of microscale structures and thin film printing. Implementation of the state-of-the-art low-temperature synthesis allowed to us successfully incorporate high concentrations of Sc3+ ions into the TiO2 lattice and improve the light absorption characteristics of the resulting materials. Without affecting the anatase structure substantially, Sc doping gave rise to an intensified absorbance capacity and provided the means for the efficient fabrication of Sc-TiO2 microarchitectures via the inkjet printing technique. The changes in the spectral and structural characteristics of the Sc-TiO2 composites were observed by Energy Dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-vis methods. The rheological parameters of the colloidal suspension based on the synthesized Sc-TiO2 nanoparticles were adapted for inkjet printing in terms of the optimal viscosity, morphology, and surface tension. The developed individual ink characteristics allowed us to produce a close coherence between the enhanced optical properties of the Sc-TiO2 prepared the sol-gel method and the inkjet-printed films. The introduced methodology features the possibility to inkjet-print doped and pure TiO2 robust films for potential large-scale fabrication.ChemE/AlgemeenChemE/Inorganic Systems Engineerin

Dural arteriovenous fistula of the torcular herophili presenting with hydrocephalus and venous congestion in an 8-month-old child: A case report

Dural arteriovenous fistulas (DAVFs) are direct communication between the dural arterial and venous systems. They are more common in adults. In children, they are relatively rare. Hydrocephalus is a common problem in pediatrics with a variety of causes. However, very few cases of hydrocephalus as a complication of DAVF have been reported in the literature. This case describes an 8-month-old male child with a large DAVF at the torcular herophili who presented with regression of milestones and hydrocephalus. Magnetic resonance imaging (MRI) on admission showed triventricular hydrocephalus and a massively dilated torcular with a compressed fourth ventricle. Angiography confirmed the presence of a DAVF at the torcula with arterial feeders from the posterior circulation. Endovascular embolization was performed with >80% embolization of the fistula with no complications. Control MRI immediately postoperative was acceptable. No cerebrospinal fluid (CSF) diversion was performed. At a 3-month follow-up, the child had attained all developmental milestones for age. MRI showed normal CSF dynamics and a further reduction in the size of the torcula. Despite being rare, DAVFs should be considered as a possible cause of pediatric hydrocephalus, and treating them can lead to a resolution of the mechanisms inducing hydrocephalus. CSF shunting should be reserved for those cases with persistent hydrocephalus and raised intracranial pressure despite endovascular treatment

Diphenylalanine-based microribbons for piezoelectric applications via inkjet printing

\u3cp\u3ePeptide-based nanostructures are very promising for nanotechnological applications because of their excellent self-assembly properties, biological and chemical flexibility, and unique multifunctional performance. However, one of the limiting factors for the integration of peptide assemblies into functional devices is poor control of their alignment and other geometrical parameters required for device fabrication. In this work, we report a novel method for the controlled deposition of one of the representative self-assembled peptides - diphenylalanine (FF) - using a commercial inkjet printer. The initial FF solution, which has been shown to readily self-assemble into different structures such as nano- and microtubes and microrods, was modified to be used as an efficient ink for the printing of aligned FF-based structures. Furthermore, during the development of the suitable ink, we were able to produce a novel type of FF conformation with high piezoelectric response and excellent stability. By using this method, ribbonlike microcrystals based on FF could be formed and precisely patterned on different surfaces. Possible mechanisms of structure formation and piezoelectric effect in printed microribbons are discussed along with the possible applications.\u3c/p\u3

Diphenylalanine-based microribbons for piezoelectric applications via inkjet printing

Peptide-based nanostructures are very promising for nanotechnological applications because of their excellent self-assembly properties, biological and chemical flexibility, and unique multifunctional performance. However, one of the limiting factors for the integration of peptide assemblies into functional devices is poor control of their alignment and other geometrical parameters required for device fabrication. In this work, we report a novel method for the controlled deposition of one of the representative self-assembled peptides - diphenylalanine (FF) - using a commercial inkjet printer. The initial FF solution, which has been shown to readily self-assemble into different structures such as nano- and microtubes and microrods, was modified to be used as an efficient ink for the printing of aligned FF-based structures. Furthermore, during the development of the suitable ink, we were able to produce a novel type of FF conformation with high piezoelectric response and excellent stability. By using this method, ribbonlike microcrystals based on FF could be formed and precisely patterned on different surfaces. Possible mechanisms of structure formation and piezoelectric effect in printed microribbons are discussed along with the possible applications