Lima, N, Baptista AC, Faustino BMM, Taborda S, Marques A, Ferreira I.
2020.
Carbon threads sweat-based supercapacitors for electronic textiles. Scientific Reports. 10:7703.
AbstractFlexible and stretchable energy-storage batteries and supercapacitors suitable for wearable electronics are at the forefront of the emerging field of intelligent textiles. In this context, the work here presented reports on the development of a symmetrical wire-based supercapacitor able to use the wearer’s sweat as the electrolyte. The inner and outer electrodes consists of a carbon-based thread functionalized with a conductive polymer (polypyrrole) which improves the electrochemical performances of the supercapacitor. The inner electrode is coated with electrospun cellulose acetate fibres, as the separator, and the outer electrode is twisted around it. The electrochemical performances of carbon-based supercapacitors were analyzed using a simulated sweat solution and displayed a specific capacitance of 2.3 F.g−1, an energy of 386.5 mWh.kg−1 and a power density of 46.4 kW.kg−1. Moreover, cycle stability and bendability studies were performed. Such energy conversion device has exhibited a stable electrochemical performance under mechanical deformation, over than 1000 cycles, which make it attractive for wearable electronics. Finally, four devices were tested by combining two supercapacitors in series with two in parallel demonstrating the ability to power a LED.
Adeoye, O, Conceição J, Serra PA, da Silva AB, Duarte N, Guedes RC, Corvo MC, Aguiar-Ricardo A, Jicsinszky L, Casimiro T, Cabral-Marques H.
2020.
Cyclodextrin solubilization and complexation of antiretroviral drug lopinavir: In silico prediction; Effects of derivatization, molar ratio and preparation method. Carbohydrate Polymers. 227:115287.: Elsevier
AbstractLopinavir (LPV) is currently used in combination with ritonavir for the clinical management of HIV infections due to its limited oral bioavailability. Herein, we report the application of an in silico method to study cyclodextrin (CyD) host-guest molecular interaction with LPV for the rational selection of the best CyD for developing a CyD based LPV delivery system. The predicted CyD, a (2-hydroxy)propyl-gamma derivative with high degree of substitution (HP17-γ-CyD) was synthesized and comparatively evaluated with γ-CyD and the commercially available HP-γ-CyD. All complexes were prepared by supercritical assisted spray drying (SASD) and co-evaporation (CoEva) at molar ratios (1:1 and 1:2); and afterwards fully characterized. Results indicate a higher LPV amorphization and solubilization ability of HP17-γ-CyD. The SASD processing technology also enhanced LPV solubilization and release from complexes. The application of in silico methodologies is a feasible approach for the rational and/or deductive development of CyD drug delivery systems.
Strohmeier, P, Honnet C, Perner-Wilson H, Teyssier M, Fruchard B, Baptista AC, Steimle J.
2020.
Demo of PolySense: How to Make Electrically Functional Textiles. CHI Conference on Human Factors in Computing Systems. :1-4.
AbstractWe demonstrate a simple and accessible method for enhancing textiles with custom piezo-resistive properties. Based on in-situ polymerization, our method offers seamless integration at the material level, preserving a textile's haptic and mechanical properties. We demonstrate how to enhance a wide set of fabrics and yarns using only readily available tools. During each demo session, conference attendees may bring textile samples which will be polymerized in a shared batch. Attendees may keep these samples. While the polymerization is happening, attendees can inspect pre-made samples and explore how these might be integrated in functional circuits. Examples objects created using polymerization include rapid manufacturing of on-body interfaces, tie-dyed motion-capture clothing, and zippers that act as potentiometers.
dos Santos, LM, Bernard FL, Polesso BB, Pinto IS, Frankenberg CC, Corvo MC, Almeida PL, Cabrita E, Menezes S, Einloft S.
2020.
Designing silica xerogels containing RTIL for CO2 capture and CO2/CH4 separation: Influence of ILs anion, cation and cation side alkyl chain length and ramification. Journal of Environmental Management. 268:110340.
AbstractCO2 separation from natural gas is considered to be a crucial strategy to mitigate global warming problems, meet product specification, pipeline specs and other application specific requirements. Silica xerogels (SX) are considered to be potential materials for CO2 capture due to their high specific surface area. Thus, a series of silica xerogels functionalized with imidazolium, phosphonium, ammonium and pyridinium-based room-temperature ionic liquids (RTILs) were synthesized. The synthesized silica xerogels were characterized by NMR, helium pycnometry, DTA-TG, BET, SEM and TEM. CO2 sorption, reusability and CO2/CH4 selectivity were assessed by the pressure-decay technique. Silica xerogels containing IL demonstrated advantages compared to RTILs used as separation solvents in CO2 capture processes including higher CO2 sorption capacity and faster sorption/desorption. Using fluorinated anion for functionalization of silica xerogels leads to a higher affinity for CO2 over CH4. The best performance was obtained by SX- [bmim] [TF2N] (223.4 mg CO2/g mg/g at 298.15 K and 20 bar). Moreover, SX- [bmim] [TF2N] showed higher CO2 sorption capacity as compared to other reported sorbents. CO2 sorption and CO2/CH4 selectivity results were submitted to an analysis of variance and the means compared using Tukey's test (5%).
Duczinski, R, Polesso BB, Bernard FL, Ferrari HZ, Almeida PL, Corvo MC, Cabrita EJ, Menezes S, Einloft S.
2020.
Enhancement of CO2/N2 selectivity and CO2 uptake by tuning concentration and chemical structure of imidazolium-based ILs immobilized in mesoporous silica. Journal of Environmental Chemical Engineering.
AbstractImidazolium-based ionic liquids (ILs) with different cation alkyl chain ([i-C5mim] or [C4mim]) and inorganic anions ([Cl−], [Tf2N−], [PF6−] and [DCA−]) were synthesized and immobilized in commercial mesoporous silica. The synthesized supported ILs (SILs) were characterized using NMR, FTIR, TGA, BET, SEM and TEM. CO2 sorption capacity, reusability and CO2/N2 selectivity were assessed by the pressure-decay technique. The effects of IL concentration, cation and anion chemical structure in CO2 sorption capacity and CO2/N2 separation performance were evaluated. Tests evidenced that the presence of branching on the cation alkyl side chain increases CO2/N2 selectivity. The immobilization of the IL [i-C5TPIm][Cl] on mesoporous silica in different concentrations (50, 20, 10 and 5 %) revealed that lower IL concentration results in higher CO2 sorption capacity. Immobilization of ILs containing fluorinated anions at low concentrations in the mesoporous silica support may promote the improvement of the CO2/N2 selectivity without interfering on CO2 sorption capacity of the original support. CO2 sorption capacity value shown by sample SIL-5 % - [i-C5TPIm][Tf2N] (79.50 ± 0.70 mg CO2 g-1) was close to the value obtained for the pristine mesoporous silica (81.70 ± 2.20 mg CO2 g-1) and the selectivity (4.30 ± 0.70) was more than twice of the one obtained for the support alone (2.32 ± 0.4). Recycle tests demonstrated that the ILs immobilized in mesoporous silica samples are stable, providing a new option to be used in CO2 capture processes.
Zanatta, M, Lopes M, Cabrita EJ, Bernardes CES, Corvo M.
2020.
Handling CO2 sorption mechanism in PIL@IL composites. Journal of CO2 Utilization. 41:101225.: Elsevier
AbstractThe mitigation of climate change effects requires the use of alternative materials and technologies to control CO2 atmospheric levels through its capture, storage and use. In this field, the current work presents the evaluation of two poly(ionic liquid)s (PILs) (poly-1-vinyl-3-ethylimidazolium acetate and hydroxide) combined with free ionic liquid (IL) 1-butyl-3-methylimidolium acetate (BMI·OAc) for CO2 capture. The sorption capacity of PIL@IL composites was evaluated under 20 bar of CO2 at 298 K. Nuclear Magnetic Resonance (NMR) spectroscopy allowed quantification of CO2 sorption (physisorption and/or chemisorption) and in situ study of the PIL−CO2 interaction mechanism. NMR in combination with Molecular Dynamics (MD) simulations suggested a 3D organization of PIL composites, maintaining a similar organization to ILs. Also, the use of aqueous solutions of PIL@IL composites was tested, identifying the optimum conditions for water activation (intrinsic water trapped inside IL structure) for chemisorption. As our main contribution, we demonstrate the possibility to control the sorption pathway towards CO2 physisorption, or CO2 conversion (chemisorption) through carbonation (HCO3−/CO32-) according to the PIL/IL ratio, ions structure and water amount. The use of PIL/IL composites is a promising advance for further CO2 reuse approaching a biomimetic carbonation process.
Mouquinho, A, Corvo MC, Almeida PL, Feio GM, Sotomayor J.
2020.
Influence of chain length of prepolymers in permanent memory effect of PDLC assessed by solid-state NMR. Liquid Crystals. 47:522–530., Number 4: Taylor & Francis
AbstractThe relationship between linear chain (ethylene oxide units) length of polymerisable monomers with morphology, electro-optical properties and 13C nuclear magnetic resonance (NMR) spectroscopy of the corresponding polymer-dispersed liquid crystal (PDLC) films was investigated. The preferred liquid crystal molecule alignment and permanent memory effect of PDLC were greatly influenced by the length of the molecular chain of prepolymers to be incorporated as a polymer matrix. By increasing the number of ethylene oxide in prepolymer chain and maintaining the number of functionalities (polymerisable groups in each monomer molecule), the permanent memory effect of PDLC increased, as proved by solid-state 13C NMR spectroscopy.