Persona:
Sanz Monasterio, Mikel

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0000-0001-6160-3583
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Sanz Monasterio
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Mikel
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2020 - 20243
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Mostrando 1 - 3 de 3
  • Miniatura
    Publicación
    Study of the Crystal Structure and Hydrogen Bonding during Cold Crystallization of Poly(trimethylene 2,5-furandicarboxylate)
    (American Chemical Society, 2024-02-25) Toledano Sanz, Óscar; Gálvez González, Óscar; Sanz Monasterio, Mikel; García Arcos, Carlos; Rebollar, Esther; Nogales, Aurora; García Gutiérrez, Mari Cruz; Santoro, Gonzalo; Irska, Izabela; Paszkiewicz, Sandra; Szymczyk, Anna; Ezquerra, Tiberio A.; https://orcid.org/0000-0002-2494-3551; https://orcid.org/0000-0002-3604-1512; https://orcid.org/0000-0003-4751-2209; https://orcid.org/0000-0002-5521-1847; https://orcid.org/0000-0002-9670-6395; https://orcid.org/0000-0001-9966-519X
    Here, we present a detailed description of the in situ isothermal crystallization of poly(trimethylene 2,5-furandicarboxylate)(PTF) as revealed by real-time Fourier transform infrared spectroscopy (FTIR) and grazing incidence wide-angle X-ray scattering (GIWAXS). From FTIR experiments, the evolution of hydrogen bonding with crystallization time can be monitored in real time, while from GIWAXS, crystal formation can be followed. Density functional theory (DFT) calculations have been used to simulate FTIR spectra for different theoretical structures, enabling a precise band assignment. In addition, based on DFT ab initio calculations, the influence of hydrogen bonding on the evolution with crystallization time can be understood. Moreover, from DFT calculations and comparison with both FTIR and GIWAXS experiments, a crystalline structure of poly(trimethylene 2,5-furandicarboxylate) is proposed. Our results demonstrate that hydrogen bonding is present in both the crystalline and the amorphous phases and its rearrangement can be considered as a significant driving force for crystallization of poly(alkylene 2,5-furanoate)s.
  • Miniatura
    Publicación
    Iodide conversion to iodate in aqueous and solid aerosols exposed to ozone
    (Royal Society of Chemistry, 2020-02-17) Moreno, Carolina; Baeza Romero, María Teresa; Sanz Monasterio, Mikel; Gálvez González, Óscar; López Arza, Vicente; Iann, James C.; Espíldora, Eva; https://orcid.org/0000-0001-6891-4982; https://orcid.org/0000-0002-8390-0949; https://orcid.org/0000-0001-6963-9812; https://orcid.org/0000-0001-6003-4497
    The aqueous-phase and surface reactions of ozone (O3) with iodide (I−) in/on seawater have been recently found to be a strong atmospheric source of iodine. In addition, ozone also reacts with I− in solid and aqueous sea-salt aerosol. However, the primary products of the heterogeneous reactions of ozone with I− have not been clarified. In this paper, solid and aqueous KI aerosols have been exposed to ozone in an aerosol flow tube system and I− and iodate (IO3−) concentrations have been measured by UV-Vis spectroscopy. The results of these experiments have been combined with a kinetic model to elucidate the primary products of the aqueous and surface reactions. The reaction of ozone with aqueous iodide has been inferred to originate different products depending on whether it occurs at the surface via O3 adsorption (product I2−) or in the aqueous phase via O3 solvation (product IO−). The surface reaction of ozone with solid KI in the presence of water vapor forms KIO3, and other species, which are likely to be gaseous. Although the reactions have been studied in aerosols, the results can be extrapolated to aqueous solutions as well.
  • Miniatura
    Publicación
    Inter and intra molecular dynamics in poly(trimethylene 2,5-furanoate) as revealed by infrared and Broadband Dielectric Spectroscopies
    (Elsevier, 2023-02-22) Gálvez González, Óscar; Toledano Sanz, Óscar; Hermoso,Francisco Javier; Linares, A.; Sanz Monasterio, Mikel; Rebollar, Esther; Nogales, Aurora; García Gutiérrez, Mari Cruz; Santoro, Gonzalo; Irska, Izabela; Paszkiewicz, Sandra; Szymczyk, Anna; Ezquerra, Tiberio A.
    Infrared spectroscopy (IR) and Broadband Dielectric Spectroscopy (BDS) experiments have been performed in poly(trimethylene 2,5-furanoate)(PTF) and poly(trimethylene terephthalate)(PTT) below their glass transition temperatures. The BDS experiments reveal a richer inter-molecular dynamic for PTT as characterized by a multimodal β relaxation in contrast with the monomodal one exhibited by PTF. The evolution with temperature of comparable IR absorption bands is very similar for PTF and PTT and shows small shifts in wavenumbers towards lower values, with exception of the band related to the stretching mode of the carbonyl group. In addition, a significant difference appears in the shape of the bands associated with the –Cdouble bondO stretching. While for PTT the absorption feature is comprised of a single component, that for PTF exhibits several components suggesting the presence of hydrogen bonds. This effect may be responsible for the monomodal shape of the β relaxation of PTF since a higher degree of intramolecular coupling between the furan ring and the rest of the monomer is expected. Density Functional Theory (DFT) calculations support the experimental results revealing that as temperature increases an increment of the syn conformations of the 2,5-furandicarboxylic acid (FDCA) moiety is likely to occur in the amorphous state. The energy gain from more stable anti to less stable syn isomers can be compensated by the formation of hydrogen bonds between interchain FDCA moieties in syn conformations. This effect may cause additional hindrance to the intermolecular dynamics of the dielectric β relaxation. It is conceivable that the hindrance exhibited by PTF in both intra and inter-molecular dynamics may play a role in the reduction of gas diffusion and permeability of PTF in comparison with PTT.