12 documents found, page 1 of 2
Bacterial nanocellulose membranes loaded with vitamin B-based ionic liquids for...
Chantereau, G.; Sharma, M.; Abednejad, A.; Vilela, C.; Costa, E. M.; Veiga, M.; Antunes, F.; Pintado, M. M.; Sèbe, G.; Coma, V.; Freire, M. G.The development of innovative bio-based skin care products has received an increase attention in the latter years. In the present work, the synthesis of original active principle ingredients based ionic liquids (ILs) with cholinium cation and vitamins B anions followed by their incorporation in bacterial nanocellulose (BC) membranes for topical applications is reported. Three ILs, namely cholinium nicotinate [C...
Resistive switching of silicon-silver thin film devices in flexible substrates
Dias, C.; Leitao, D. C.; Freire, C. S. R.; H, Gomes; Cardoso, S.; Ventura, J.Novel applications for memory devices demand nanoscale flexible structures. In particular, resistive switching (RS) devices are promising candidates for wearable and implantable technologies. Here, the Pt/Si/Ag/TiW metal-insulator-metal structure was fabricated and characterized on top of flexible substrates using a straightforward microfabrication process. We also showed that these substrates are compatible wi...
New unsaturated copolyesters based on 2,5-furandicarboxylic acid and their cros...
Sousa, A. F.; Fonseca, A. C.; Serra, A. C.; Freire, C. S. R.; Silvestre, A. J. D.; Coelho, J. F. J.The synthesis and characterisation of a novel family of unsaturated polyesters (UPs) and their crosslinked resins (UPRs) based on 2,5-furandicarboxylic acid (FDCA) are reported. Their original features stem from the use of FDCA as the aromatic monomer, and also from the fact that UPs are entirely based on renewable resources, oppositely to most reported materials which are typically based on petrochemicals or i...
Bacterial cellulose membranes as drug delivery systems: An in vivo skin compati...
Almeida, I. F.; Pereira, T.; Silva, N. H. C. S.; Gomes, F. P.; Silvestre, A. J. D.; Freire, C. S. R.; Sousa Lobo, J. M.; Costa, P. C.Bacterial cellulose (BC) is a highly pure form of cellulose, produced in the form of a swollen membrane by several bacteria that demonstrated to be able to modulate the skin release of model drugs. In the present study, the skin irritation potential of BC was evaluated in human subjects. BC membranes with and without glycerin (acting as plasticizer) were tested. No significant differences were observed for tran...
Self-standing chitosan films as dielectrics in organic thin-film transistors
Morgado, J.; Pereira, A. T.; Braganca, A. M.; Ferreira, Q.; Fernandes, S. C. M.; Freire, C. S. R.; Silvestre, A. J. D.; Pascoal Neto, C.; Alcacer, L.Organic thin film transistors, using self-standing 50 gin thick chitosan films as dielectric, are fabricated using sublimed pentacene or two conjugated polymers deposited by spin coating as semiconductors. Field-effect inobilities are found to be similar to values obtained with other dielectrics and, in the case of pentacene, a value (0.13 cm(2)/(V.S) comparable to high performing transistors was determined. In...
Functionalized chitosan-based coatings for active corrosion protection
Carneiro, J.; Tedim, J.; Fernandes, S. C. M.; Freire, C. S. R.; Gandini, A.; Ferreira, M. G. S.; Zheludkevich, M. L.Chitosan-based coatings were suggested in this work as a \"green\" alternative for active corrosion protection of aluminum alloys. 2-Mercaptobenzothiazole (MBT) was used here as an efficient corrosion inhibitor for AA2024. The electrochemical impedance spectroscopy has demonstrated a strong inhibiting action of MBT showing no corrosion attack even after one week in full immersion tests when MBT-loaded chitosan ...
Lipophilic extractives from the bark of Eucalyptus grandis x globulus, a rich s...
Patinha, D. J. S.; Domingues, R. M. A.; Villaverde, J. J.; Silva, A. M. S.; Silva, C. M.; Freire, C. S. R.; Pascoal Neto, C.; Silvestre, A. J. D.The chemical composition of the lipohilic extracts of the inner and outer barks of Eucalyptus grandis x globulus, cultivated in Portugal, was studied by gas chromatography-mass spectrometry. The two bark fractions show different chemical compositions. beta-Sitosterol is the most abundant compound in the inner bark (82 mg kg(-1)), while long chain aliphatic alcohols are the main family of components accounting f...
Cellulose/iron oxide hybrids as multifunctional pigments in thermoplastic starc...
Neves, M. C.; Freire, C. S. R.; Costa, B. F. O.; Pascoal Neto, C.; Trindade, T.Cellulose/iron oxide hybrids were prepared by the controlled hydrolysis of FeC2O4 in the presence of vegetable and bacterial cellulose fibres as substrates. By varying the relative amount of FeC2O4 and NaOH, either hematite or magnetic iron oxides were grown at the cellulose fibres surfaces. This chemical strategy was used for the production of a number of materials, whose coloristic properties associated to th...
Chitosan-based self-healing protective coatings doped with cerium nitrate for c...
Carneiro, J.; Tedim, J.; Fernandes, S. C. M.; Freire, C. S. R.; Silvestre, A. J. D.; Gandini, A.; Ferreira, M. G. S.; Zheludkevich, M. L.The good film forming ability, specific solubility and versatile chemical functionalization of chitosan make it a promising candidate for "green" protective coatings. In the present work, these features are exploited together with chitosan high complexing ability to obtain inhibitor-containing anticorrosion coatings for active protection of aluminum alloys. The functionalization of chitosan with fluorinated sub...
High value triterpenic compounds from the outer barks of several Eucalyptus spe...
Domingues, R. M. A.; Sousa, G. D. A.; Silva, C. M.; Freire, C. S. R.; Silvestre, A. J. D.; Neto, C. PascoalThe chemical composition of the lipophilic extracts of the inner and outer bark fractions of Eucalyptus grandis and Eucalyptus urograndis (E. grandis x Eucalyptus urophylla) cultivated in Brazil and Eucalyptus maidenii, cultivated in Portugal was studied by gas chromatography-mass spectrometry. The extracts were shown to be mainly composed of triterpenic compounds (along with mono and sesquiterpenes in E. maide...