Análise e perspectivas de uma empresa de pesquisa e desenvolvimento rumo à gestão por processos.

bitstream/CNPDIA-2009-09/11847/1/CiT35_2006.pd

Lithium-doped silk fibroin films for application in electrochromic devices

Silk fibroin (SF) is a commonly available natural biopolymer produced in specialized glands of arthropods, with a long history of use in textile production and also in health cares. The exceptional intrinsic properties of these fibers, such as self-assembly, machinability, biocompatibility, biodegradation or non-toxicity, offer a wide range of exciting opportunities [1]. It has long been recognized that silk can be a rich source of inspiration for designing new materials with tailored properties, enhanced performance and high added value for targeted applications, opening exciting new prospects in the domain of materials science and related technological fields, including bio-friendly integration, miniaturization and multifunctionalization. In recent years it has been demonstrated that fibroin is an excellent material for active components in optics and photonics devices. Progress in new technological fields such as optics, photonics and electronics are emerging [2,3]. The incorporation of polymer electrolytes as components of various devices (advanced batteries, smart windows, displays and supercapacitors) offers significant advantages with respect to traditional electrolytes, including enhanced reliability and improved safety. SF films are particularly attractive in this context. They have near-perfect transparency across the VIS range, surface flatness (together with outstanding mechanical robustness), ability to replicate patterned substrates and their thickness may be easily tailored from a few nanometers to hundreds of micrometers through spin-casting of a silk solution into subtract. Moreover, fibroin can be added to other biocomponents or salts in order to modify the biomaterial properties leading to optimized and total different functions. Preliminary tests performed with a prototype electrochromic device (ECD) incorporating SF films doped with lithium triflate and lithium tetrafluoroborate (LiTFSI and LiBF4, respectively) as electrolyte and WO3 as cathodic electrochromic layer, are extremely encouraging. Aiming to evaluate the performance of the ion conducting SF membranes doped with LiTFSI and LiBF4 (SF-Li), small ECDs with glass/ITO/WO3/SF-Li/CeO2-TiO2/ITO/glass configuration were assembled and characterized. The device exhibited, after 4500 cycles, the insertion of charge at -3.0 V reached –1.1 mC.cm-2 in 15 s. After 4500 cycles the window glass-staining, glass/ITO/WO3/Fibrin-Li salts electrolyte/CeO2-TiO2/ITO/glass configuration was reversible and featured a T 8 % at λ = 686 n

Polymer electrolytes for electrochromic devices through solvent casting and sol-gel routes

Ionically conductive membranes of gelatin and d-PCL(530)/siloxane doped with cyano-based ionic liquids (ILs) were prepared through solvent casting and sol-gel methods, respectively. The membranes were characterized in terms of ionic conductivity, thermal behavior, morphology, and structure. All samples, except the d-PCL(530)/siloxane matrix, exhibited a predominantly amorphous morphology. The samples prepared through solvent casting and sol-gel displayed a minimum thermal stability of 170 and 230 ºC, respectively. The ionic conductivity varied accordingly with the type, quantity, and length of the alkyl chain of the cation of the ILs. The sample with the highest ionic conductivity was gelatin0.5[C2mim][N(CN)2] with 2.40 x 10-3 S. cm-1 at 25 ºC and 1.68 x 10-2 S. cm-1 at 95 ºC. The good results of ionic conductivity encouraged the assembly and characterization of prototypes of electrochromic devices (ECDs). The best results were obtained with glass/ITO/WO3/gelatin1[C2mim][SCN]/CeO2-TiO2/ITO/glass configuration that showed a fast color switching time (~ 15 s) and a good open circuit memory (~ 4 hours). The ECD changed its color from pale blue to transparent, and its charge density decreased from -17.53 to - 2.71 mC. cm-2 during 640 color/bleaching cycles.This work was supported by Fundação para a Ciência e a Tecnologia (FCT) in the framework of the Research unit GREEN-it "Bioresources for Sustainability" (UID/Multi/04551/2013), Laboratório Associado para a Química Verde – Tecnologias e Processos Limpos-LAQV (UID/QUI/50006/2013), grant SRFH/BD/90366/2012 (R.L.) and a contract under Investigador FCT 2012 program (J.M.S.S.E.). It was also co-financed by FEDER through the COMPETE Program and PT2020 Partnership Agreement (POCI-01-0145-FEDER – 007265). M.M. Silva acknowledges CNPq (PVE grant 406617/2013-9) for the mobility grant provided by this institution. A. Pawlicka and R.C. Sabadini acknowledge CNPq (grant 305029/2013-4 and 152252/2016-9), and F.C. Sentanin acknowledges CAPES (grant PNPD20131739- 33002045017P6).info:eu-repo/semantics/publishedVersio

Investigation of polymer electrolyte based on agar and ionic liquids

The possibility to use natural polymer as ionic conducting matrix was investigated in this study. Samples of agarbased electrolytes with different ionic liquids were prepared and characterized by physical and chemical analyses. The ionic liquids used in this work were 1-ethyl-3-methylimidazolium ethylsulfate, [C2mim][C2SO4], 1-ethyl-3-methylimidazolium acetate, [C2mim][OAc] and trimethyl-ethanolammonium acetate, [Ch][OAc]. Samples of solvent-free electrolytes were prepared and characterized by ionic conductivity measurements, thermal analysis, electrochemical stability, X-ray diffraction, scanning electron microscopy and Fourier Transform infrared spectroscopy. Electrolyte samples are thermally stable up to approximately 190°C. All the materials synthesized are semicrystalline. The electrochemical stability domain of all samples is about 2.0 V versus Li/Li+. The preliminary studies carried out with electrochromic devices (ECDs) incorporating optimized compositions have confirmed that these materials may perform as satisfactory multifunctional component layers in the field of ‘smart windows’, as well as ECD-based devices

Electrochemical applications of electrolytes based on ionic liquids

The potential utility of room temperature ionic liquids as electrolytes in current electrochemical applications has been explored. Hence, the electrochemical behavior of [Ni(tmc)]Br2 complex at a glassy carbon electrode in the absence or in the presence of unsaturated halides in the ionic liquids, 1-ethyl-3- methylimidazolium ethylsulfate, [C2mim][C2SO4] and N,N,Ntrimethyl- N-(2-hydroxyethyl) ammonium bis(trifluoromethylsulfonyl)imide, [N1 1 1 2(OH)][NTf2], has been examined by cyclic voltammetry. It was observed that [Ni(tmc)]2+ complex is reduced in a reversible one-electron step and the electrogenerated [Ni(tmc)]+ complex catalytically reduces the carbon-halogen bond of unsaturated halides. The potencial use of natural ionic conducting polymer matrixes was also investigated. Samples of natural macromolecules-based electrolytes with the ionic liquid 1-ethyl- 3-methylimidazolium ethylsulfate, [C2mim][C2SO4], were prepared and characterized. The preliminary studies carried out with electrochromic devices (ECDs) incorporating optimized compositions have confirmed that these materials may perform as satisfactory multifunctional component layers in the field of ECD-based devices.Fundação para a Ciência e a Tecnologia (FCT

Obtaining and properties of torulene from Rhodotorula glutinis yeast

Orientador: Delia Rodriguez-AmayaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Os carotenóides são corantes naturais, alguns dos quais são precursores de vitamina A. Desde a década passada, tem sido atribuído a estes compostos um importante papel na diminuição do risco de várias doenças degenerativas. Com estas funções vitais, a procura por fontes intensificou-se mundialmente. A produção biotecnológica de carotenóides específicos, utilizando bactérias, fungos e leveduras, vem despertando crescente interesse. O presente trabalho teve como objetivos otimizar a extração dos carotenóides de Rhodotorula glutinis, estimular a produção de carotenóides pela adição de ácido mevalônico, substituir o meio de cultivo por substrato de baixo custo e avaliar a estabilidade e degradação de toruleno. O capítulo 1 apresenta uma revisão bibliográfica sobre a biossíntese de carotenóides e a produção biotecnológica desses pigmentos nos últimos dez anos, destacando a produção por bactérias, algas e fungos. O segundo capítulo visa otimizar a extração dos carotenóides da levedura Rhodotorula glutinis e avaliar o efeito de diferentes concentrações de ácido mevalônico na produção de carotenóides. Por ser um precursor chave no caminho biossintético dos carotenóides em leveduras, este composto influenciou de modo significativo a produção dos pigmentos. Apesar da quantidade de biomassa não ter sido afetada, a produção de carotenóides totais aumentou em até 114% e o rendimento de toruleno e de b-caroteno aumentou 157% e 168%, respectivamente. O Capítulo 3 tem o intuito de baixar o custo de produção de carotenóides pela levedura em estudo, através da substituição do meio de cultura usual YM por um residuo da industria da mandioca, a manipueira, substrato rico em nutrientes. Para otimizar a producao dos pigmentos, realizou-se um planejamento fatorial completo de quatro variaveis, a saber pH, temperatura, agitacao e volume de inoculo. A condicao que melhor favoreceu o rendimento de carotenoides foi 26°C, 250 rpm de agitacao, pH 7,0 e 10% de volume de inoculo. Nessa condicao, a producao de carotenoides totais foi de 2068 ?g/L de meio de cultura. O tradicional meio YM proporcionou a producao de apenas 899 ?g/L de meio de cultura de carotenoides totais. O quarto capitulo tem por objetivo avaliar a estabilidade do carotenoide toruleno produzido por Rhodotorula, em comparacao com os carotenoides bem conhecidos licopeno e ?-caroteno. Para isso, foram montados sistemas modelos de baixa umidade, utilizando como matriz celulose microcristalina, que ficaram expostos durante 15 dias a luz ou ao abrigo da mesma. O carotenoide que mais sofreu degradacao foi o licopeno, seguido de ?-caroteno e toruleno. O Capitulo 5 visa investigar a degradacao oxidativa do toruleno e os compostos volateis produzidos durante esse processo. Para atingir esse objetivo, foram montados sistemas modelo de baixa umidade, com matriz de celulose microcristalina, em frascos de vidro, com injecao de fluxo de oxigenio. Houve a formacao de diversos compostos de degradacao, dos quais os que mais se destacaram, quantitativamente, foram metacroleina, prenal, 2,6- dimetil-hepta-2,4-dieno, 6-metil-hept-5-en-2-ona, 2-etil-hexanol, 2-etenil- 1,3,3-trimetil-ciclohexeno e 3,3-dimetil-acetaldeido-ciclohexilidenoAbstract: Carotenoids are natural colorants, some of which are precursors of vitamin A. Since the past decade, an important role in reducing the risk of various degenerative diseases was attributed to these compounds. With these vital functions, the search for sources has intensified worldwide. The biotechnological production of specific carotenoids, using bacteria, fungi and yeasts, have attracted increasing interest. This study had the objective of optimizing the extraction of carotenoids from Rhodotorula glutinis, stimulating the production of carotenoids with mevalonic acid, substituting the medium with low-cost substrate and evaluating the stability and degradation of torulene. Chapter 1 presents a review of the biosynthesis of carotenoids and biotechnological production of these pigments in the last ten years, highlighting the production by bacteria, algae and fungi. The second chapter aims to optimize the extraction of carotenoids from the yeast Rhodotorula glutinis and assessing the effect of different concentrations of mevalonic acid on the production of carotenoids. Being a key precursor in the biosynthetic pathway of carotenoids in yeasts, it significantly influenced the production of pigments. Although the amount of biomass was not affected, the production of total carotenoid increased by 114% and the yield of torulene and ?-carotene increased by 157% and 168%, respectively. Chapter 3 is intended to lower the cost of production of carotenoids by the yeast under investigation, by replacing the usual culture medium YM with a sub-product of the cassava industry, the nutrient-rich substrate manipueira. To optimize the production of pigments, a full factorial design was used with four variables: pH, temperature, agitation and inoculum volume. The condition that favored yield of carotenoids was: 26°C, 250 rpm agitation, pH 7.0 and 10% volume of inoculum. In this condition, the production of carotenoids was 2068 mg/L of culture medium. The traditional YM provided the production of only 899 mg/L of culture medium of carotenoids. The fourth chapter aims to evaluate the stability of torulene produced by Rhodotorula, compared with well-known carotenoids, lycopene and b-carotene. For this purpose, model systems of low moisture were mounted, using microcrystalline cellulose as the matrix, which were kept in the dark or exposed to light for 15 days. The carotenoid that suffered the most degradation was lycopene, followed by b-carotene and torulene. Chapter 5 investigates the oxidative degradation of torulene and the volatile compounds produced during this process. To achieve this goal, model systems of low moisture were mounted, with microcrystalline cellulose matrix, in glass bottle, with injection of oxygen flow. Several degradation compounds were formed, of which the following compounds stood out quantitatively: methacrolein, prenal, 2,6-dimethyl-hepta-2,4-diene, 6-methyl-hept-5-en-2- one, 2-ethylhexanol, 2-ethenyl-1,3,3-trimethyl-cyclohexene and 3,3-dimethylciclohexilideno acetaldehydeDoutoradoCiência de AlimentosDoutor em Ciência de Alimento

Nanocomposite polymer electrolytes of sodium alginate and montmorillonite clay

Nanocomposite polymer electrolytes (NPEs) were synthesized using sodium alginate (Alg) and either sodium (SCa-3-Na+)- or lithium (SCa-3-Li+)-modified montmorillonite clays. The samples were characterized by structural, optical, and electrical properties. SCa-3-Na+ and SCa-3-Li+ clays’ X-ray structural analyses revealed peaks at 2θ = 7.2° and 6.7° that corresponded to the interlamellar distances of 12.3 and 12.8 Å, respectively. Alg-based NPEs X-ray diffractograms showed exfoliated structures for samples with low clay percentages. The increase of clay content promoted the formation of intercalated structures. Electrochemical Impedance Spectroscopy revealed that Alg-based NPEs with 5 wt% of SCa-3-Na+ clay presented the highest conductivity of 1.96 × 10−2 S/cm2, and Alg with 10 wt% of SCa-3-Li+ showed conductivity of 1.30 × 10−2 S/cm2, both measured at 70 °C. From UV-Vis spectroscopy, it was possible to infer that increasing concentration of clay promoted a decrease of the samples’ transmittance and, consequently, an increase of their reflectance.This research was partially founded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 (proc. PNPD20131739-33002045017P6, F. Sentanin fellowship no. 1573926)

LITHIUM-DOPED SILK FIBROIN FILMS FOR APPLICATION IN ELECTROCHROMIC DEVICES

Abstract Silk fibroin (SF) is a commonly available natural biopolymer produced in specialized glands of arthropods, with a long history of use in textile production and also in health cares. The exceptional intrinsic properties of these fibers, such as self-assembly, machinability, biocompatibility, biodegradation or non-toxicity, offer a wide range of exciting opportunitie