| 101. |
- Maroni, Fabio, et al.
(author)
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V2O5 Cryogel: A Versatile Electrode for All Solid State Lithium Batteries
- 2019
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 166:16, s. A3927-A3931
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Journal article (peer-reviewed)abstract
- All solid-state lithium batteries (ASLB) are paving the attention of the battery community due to the possibility of improving safety at good energy level. Their future development requires the investigation of new electrodes chemistries both based on intercalation or conversion mechanism. In this work we report on the synthesis and characterization of a V2O5 cryogel electrode and its application in ASLB. The combination of V2O5 cryogel and a solid-state electrolyte shows appealing properties of high capacity and enhanced safety.
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| 102. |
- Martinelli, Anna, 1978, et al.
(author)
-
A structural study on ionic-liquid-based polymer electrolyte membranes
- 2007
-
In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 154:8, s. G183-G187
-
Journal article (peer-reviewed)abstract
- We have investigated novel proton conducting membranes synthesized through the gelification of poly(vinylidene fluoride-co-hexafluoropropylene) in aprotic ionic liquids. Mobile protons were introduced by doping the system with the strong bis(trifluoromethanesulfonyl)imide acid (HTFSI), which is chemically compatible with the ionic liquids through the common TFSI- anion. The obtained membranes are thermally stable up to 115°C set by the melting of the polymer phase. At this temperature, the conductivity is on the order of 10-2 S cm-1. Raman and infrared spectroscopy show no chemical interactions between the components, indicating that the bulklike nature of the doped ionic liquids preserved within the membrane, as is the thermal stability and the high conductivity. © 2007 The Electrochemical Society.
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| 103. |
- Martinelli, Anna, 1978, et al.
(author)
-
A study on the state of PWA in PVDF-based proton conducting membranes by Raman spectroscopy
- 2007
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In: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 178:7-10, s. 527-531
-
Journal article (peer-reviewed)abstract
- Polymer composite proton conducting membranes with increasing amount of tungstophosphoric acid (PWA) have been synthesized starting from poly(vinylidene) fluoride and alumina. Membranes could be prepared with an acid loading up to 16.7 wt.%. The conductivity of the membranes increases with acid loading up to 10- 3 Scm- 1 at the highest loading. The membrane matrices have a good thermal stability up to 240 °C, however a loss of water absorbed during the preparation procedure is observed at a considerably lower temperature. Raman spectroscopy showed that in the membrane the polymer adopts a conformation that could promote a separation into hydrophilic/hydrophobic sites. An interaction between alumina and PWA is also found that might limit the conductivity of the membranes.
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| 104. |
- Martinelli, Anna, 1978, et al.
(author)
-
Conformational evolution of TFSI− in protic and aprotic ionic liquids
- 2011
-
In: Journal of Raman Spectroscopy. - 0377-0486 .- 1097-4555.
-
Journal article (peer-reviewed)abstract
- We here report on the conformational evolution of the bis(trifluoromethanesulfonyl)imide anion (TFSI−) in protic and aprotic TFSI−-based ionic liquids as a function of temperature. The investigation is performed by Raman spectroscopy in the spectral ranges 240-380 cm−1 and 715-765 cm−1, where the interference from bands due to the cations is negligible. The contribution from each TFSI− conformation, i.e. the cisoid (C1) and the transoid (C2), is quantified in order to estimate the enthalpy of conformational change, ΔH, which is found to be in the range 3.4–7.3 kJ/mol in the liquid state. Conformational information is for the first time determined from the 740 cm−1 band, which previously mainly has been used as an indicator of ion-ion interactions. The similarity in ΔH values obtained from the two spectral ranges demonstrates the validity of using also the 740 cm−1 band for the quantification of the TFSI conformational evolution.
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| 105. |
- Martinelli, Anna, 1978, et al.
(author)
-
Phase behavior and ionic conductivity in LiTFSI doped ionic liquids of the pyrrolidinium cation and TFSI anion
- 2009
-
In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 113:32, s. 11247-11251
-
Journal article (peer-reviewed)abstract
- The phase behavior and the ionic conductivity of ionic liquids (ILs) of the N-alkyl-N-alkylpyrrolidinium (PYR xy ) cation and the bis(trifluoromethanesulfonyl)imide (TFSI) anion are investigated upon addition of LiTFSI salt. We compare the case of two new ILs of the PYR 2y cation (where 2 is ethyl and y is butyl or propyl) with that of the PYR 14 (where 1 is methyl and 4 is butyl). We find that the addition of LiTFSI increases the glass transition temperature, decreases the melting temperature and the heat of fusion and, in the ILs of the PYR 2y family, suppresses crystallization. In the solid state, significant ionic conductivities are found, being as high as 10 -5 Scm -1 , strongly increasing with Li + concentration. The opposite trend is found in the liquid state, where the conductivity is on the order of 10 -3 -10 -2 Scm -1 at room temperature. A T g -scaled Arrhenius plot shows that the liquid-state ionic conductivity in these systems is mainly governed by viscosity and that the fragility of the liquids is slightly influenced by the structural modifications on the cation. © 2009 American Chemical Society.
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| 106. |
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| 107. |
- Martinelli, Anna, 1978, et al.
(author)
-
Structural analysis of PVA-based proton conducting membranes
- 2006
-
In: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 177:26-32, s. 2431-2435
-
Journal article (peer-reviewed)abstract
- We have synthesized and characterized a new family of proton conducting membranes based on cross-linked poly(vinyl alcohol), PVA, and functionalized silica filler. Glutaraldehyde, GLA, was used as the cross-linking agent in order to improve chemical and thermal stabilities. The functionalization of the silica particles is such that terminal -SO 3 H groups are formed during membrane preparation, thus possibly providing additional mobile protons. We find that the crystallinity of the PVA-based membranes is enhanced by the presence of the functionalized silica particles, whereas it is reduced by means of cross-linking. The thermal stability of the ternary system PVA:GLA:silica is improved due to the additive contribution of GLA and silica. The conductivity of membranes swelled in a sulfuric acid solution was found to be of the order of 10 - 1 S cm - 1 . © 2006 Elsevier B.V. All rights reserved.
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| 108. |
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| 109. |
- Martins, Murillo L., et al.
(author)
-
Encapsulation of paclitaxel into a bio-nanocomposite. A study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy
- 2015
-
In: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 83
-
Conference paper (peer-reviewed)abstract
- The anticancer drug paclitaxel was encapsulated into a bio-nanocomposite formed by magnetic nanoparticles, chitosan and apatite. The aim of this drug carrier is to provide a new perspective against breast cancer. The dynamics of the pure and encapsulated drug were investigated in order to verify possible molecular changes caused by the encapsulation, as well as to follow which interactions may occur between paclitaxel and the composite. Fourier transformed infrared spectroscopy, thermal analysis, inelastic and quasi-elastic neutron scattering experiments were performed. These very preliminary results suggest the successful encapsulation of the drug.
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| 110. |
- Martins, Murillo L, et al.
(author)
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Probing the dynamics of complexed local anesthetics via neutron scattering spectroscopy and DFT calculations
- 2017
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In: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 524:1-2, s. 397-406
-
Journal article (peer-reviewed)abstract
- Since potential changes in the dynamics and mobility of drugs upon complexation for delivery may affect their ultimate efficacy, we have investigated the dynamics of two local anesthetic molecules, bupivacaine (BVC, C18H28N2O) and ropivacaine (RVC, C17H26N2O), in both their crystalline forms and complexed with water-soluble oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The study was carried out by neutron scattering spectroscopy, along with thermal analysis, and density functional theory computation. Mean square displacements suggest that RVC may be less flexible in crystalline form than BVC, but both molecules exhibit very similar dynamics when confined in HP-β-CD. The use of vibrational analysis by density functional theory (DFT) made possible the identification of molecular modes that are most affected in both molecules by insertion into HP-β-CD, namely those of the piperidine rings and methyl groups. Nonetheless, the somewhat greater structure in the vibrational spectrum at room temperature of complexed RVC than that of BVC, suggests that the effects of complexation are more severe for the latter. This unique approach to the molecular level study of encapsulated drugs should lead to deeper understanding of their mobility and the respective release dynamics.
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