BUSCADOR RECOLECTA

The interest in new materials with specific properties has increased because they are essential for the environmental and technological needs of our society. Among them, silica hybrid
xerogels have emerged as promising candidates due to their simple preparation and tunability: when
they are synthesised, depending on the organic precursor and its concentration, their properties
can be modulated, and thus, it is possible to prepare materials with à la carte porosity and surface
chemistry. This research aims to design two new series of silica hybrid xerogels by co-condensation of
tetraethoxysilane (TEOS) with triethoxy(p-tolyl)silane (MPhTEOS) or 1,4-bis(triethoxysilyl)benzene
(Ph(TEOS)2 and to determine their chemical and textural properties based on a variety of characterisation techniques (FT-IR, 29Si NMR, X-ray diffraction and N2
, CO2 and water vapour adsorption,
among others). The information gathered from these techniques reveals that depending on the
organic precursor and its molar percentage, materials with different porosity, hydrophilicity and local
order are obtained, evidencing the easy modulation of their properties. The ultimate goal of this
study is to prepare materials suitable for a variety of applications, such as adsorbents for pollutants,
catalysts, films for solar cells or coatings for optic fibre sensors., The authors gratefully acknowledge the financial support received from the “Ministerio de Ciencia e Innovación” from Spain (PID2020-113558RB-C42), and from the Public University of Navarre, with the project “Impulso de la creatividad y la innovación a través de proyectos en bachiller de investigación”. G.C.-Q. is thankful to the “Ministerio de Universidades” of the Spanish government for the “Formación de Profesorado Universitario (FPU)” grant (FPU18/03467). M.V.L.-R. acknowledges the financial support from the FEDER 2014-2020 Operative Program and the “Junta de Andalucía”, Spain (Projects FEDER-UJA-1380629), and M.E.-V. is thankful to the Public University of Navarre for the project “Jóvenes Investigadores UPNA 2022” (PJUPNA18-2022).

Hybrid magnetic nanoparticles made up of an iron oxide, Fe3O4, core and a mesoporous SiO2 shell with high magnetization and a large surface area were proposed as an efficient drug delivery platform. The core/shell structure was synthesized by two seed-mediated growth steps combining solvothermal and sol—gel approaches and using organic molecules as a porous scaffolding template. The system presents a mean particle diameter of 30(5) nm (9 nm magnetic core diameter and 10 nm silica shell thickness) with superparamagnetic behavior, saturation magnetization of 32 emu/g, and a significant AC magnetic-field-induced heating response (SAR = 63 W/gFe3O4, measured at an amplitude of 400 Oe and a frequency of 307 kHz). Using ibuprofen as a model drug, the specific surface area (231 m2/g) of the porous structure exhibits a high molecule loading capacity (10 wt %), and controlled drug release efficiency (67%) can be achieved using the external AC magnetic field for short time periods (5 min), showing faster and higher drug desorption compared to that of similar stimulus-responsive iron oxide-based nanocarriers. In addition, it is demonstrated that the magnetic field-induced drug release shows higher efficiency compared to that of the sustained release at fixed temperatures (47 and 53% for 37 and 42 °C, respectively), considering that the maximum temperature reached during the exposure to the magnetic field is well below (31 °C). Therefore, it can be hypothesized that short periods of exposure to the oscillating field induce much greater heating within the nanoparticles than in the external solution., A grant was funded within the framework of "Ayudas para la contratación de personal investigador y tecnológico 2020", Navarra Governement. The Spanish government is acknowledged for the HIPERNANO research network (RED2018-555102626-T). The authors gratefully acknowledge the financial support received from "Ministerio de Ciencia e Innovación" from Spain (PID2020-113558RB-C42). A.L.-O. acknowledges support from the Universidad Pública de Navarra (grant no. PJUPNA2020).

Titanium silicalites (TS) are well-known materials for their use in industrial oxidation reactions, and although they are used as photocatalysts, their activity is limited. Therefore, numerous synthetic strategies are investigated to improve their photocatalytic activity. Herein, three series of modified titanium silicalites are synthesized using three different organotriethoxysilanes at different molar percentages with the aim of modifying the structure of the zeolite, both at a porous and chemical level, to obtain materials with high photocatalytic activity. The study of their morphological, textural, chemical, and UV–vis light absorption properties through various characterization techniques has allowed the selection of the best candidates to test their photoactivity in the degradation of venlafaxine, an antidepressant drug that persists as a contaminant in wastewater and has serious neurotoxic effects. Materials synthesized using a 5% molar percentage of RTEOS and 10% of PhTEOS (Ph = phenyl) are able to degrade venlafaxine, whereas the reference material does not show any photocatalytic activity. These results lead the way to use this synthetic strategy to develop titanium silicates and optimize their photocatalytic activity in degradation reactions of different pollutants., The authors gratefully acknowledge financial support from Ministerio de Ciencia e Innovación, Government of Spain (PID2020-113558RB-C42), and from portuguese national funds through FCT/MCTES (PIDDAC): LSRE-LCM, UIDB/50020/2020 (DOI: 10.54499/UIDB/50020/2020) and UIDP/50020/2020 (DOI: 10.54499/UIDP/50020/2020); and ALiCE, LA/P/0045/2020 (DOI: 10.54499/LA/P/0045/2020. G.C.-Q thanks Ministerio de Universidades, Government of Spain, for a predoctoral grant within the Formación de Profesorado Universitario (FPU) program (FPU18/03467) and the Government of Navarre, for a predoctoral international mobility grant (0011-3564-2022-000035). M.J.S. acknowledges FCT funding under the Scientific Employment Stimulus - Institutional Call (CEECINST/00010/2021). M.V.L-R acknowledges financial support from Ministerio de Ciencia e Innovación, Government of Spain (PID2022-142169OB-I00), and from FEDER 2014-2020 Operative Program and Junta de Andalucía, Spain (FEDER-UJA-1380629). M.E.-V. thanks UPNA for the project Jóvenes Investigadores UPNA 2022 (PJUPNA18-2022).

The incorporation of organic groups into sol-gel silica materials is known to have a noticeable impact on the properties and structure of the resulting xerogels due to the combination of the properties inherent to the organic fragments (functionality and flexibility) with the mechanical and structural stability of the inorganic matrix. However, the reduction of the inorganic content in the materials could be detrimental to their thermal stability properties, limiting the range of their potential applications. Therefore, this work aims to evaluate the thermal stability of hybrid inorganic-organic silica xerogels prepared from mixtures of tetraethoxysilane and organochlorinated triethoxysilane precursors. To this end, a series of four materials with a molar percentage of organochlorinated precursor fixed at 10%, but differing in the type of organic group (chloroalkyls varying in the alkyl-chain length and chlorophenyl), has been selected as model case study. The gases and vapors released during the thermal decomposition of the samples under N2 atmosphere have been analyzed and their components determined and quantified using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrophotometer and to a gas chromatography-mass spectrometry unit. These analyses have allowed to identify up to three different thermal events for the pyrolysis of the organochlorinated xerogel materials and to elucidate the reaction pathways associated with such processes. These mechanisms have been found to be strongly dependent on the specific nature of the organic group., This work was supported by the projects PID2020-113558RB-C42, PID2022-137437OB-I00 and PID2022-142169OB-I00, financed by MCIN/AEI/10.13039/501100011033

La investigación presentada en esta memoria tiene como objetivo preparar xerogeles híbridos de silicio y silicalitas de titanio modificadas, utilizando diversos precursores orgánicos, y estudiar la influencia de su naturaleza en las propiedades texturales y químicas de los nuevos materiales, con el fin de controlar su química superficial y textura, buscando la mayor versatilidad y el material mejor adaptado a la aplicación concreta que se le pretende dar, que son, en este estudio, la preparación de membranas de sensores químicos de fibra óptica y la degradación fotocatalítica de venlafaxina., The research presented in this doctoral dissertation is focused on the synthesis of hybrid silica xerogels and modified titanium silicalites using different organic precursors, and on the study of their influence on the textural and chemical properties of the new materials. The main goal is to obtain versatile and well-adapted materials for specific applications, which are the preparation of membranes for optical fibre sensors and the photocatalytic degradation of venlafaxine., This doctoral thesis has been developed thanks to the funding received from Ministerio de Economia y Competitividad (Project MAT2016-78155-C2-2-R) and Ministerio de Ciencia e Innovación (Project PID2020-113558RB-C42) from the Government of Spain. The author would also like to acknowledge the financial support provided by the Ministerio de Universidades of the Government of Spain, for the predoctoral grant (2020-2024) within the Formación de Profesorado Universitario (FPU) program (FPU18/03467); and the Government of Navarre, for a predoctoral international mobility grant (0011-3564-2022-000035), which allowed the author to complete a three months doctoral stay (2022) in the Faculty of chemical engineering at the University of Porto (FEUP)., Programa de Doctorado en Ciencias y Tecnologías Industriales (RD 99/2011), Industria Zientzietako eta Teknologietako Doktoretza Programa (ED 99/2011)

The search for new materials with improved properties for advanced applications is, nowadays, one of the most relevant and booming fields for scientists due to the environmental and technological needs of our society. Within this demand, hybrid siliceous materials, made out of organic and inorganic species (ORMOSILs), have emerged as an alternative with endless chemical and textural possibilities by incorporating in their structure the properties of inorganic compounds (i.e., mechanical, thermal, and structural stability) in synergy with those of organic compounds (functionality and flexibility), and thus, bestowing the material with unique properties, which allow access to multiple applications. In this work, synthesis using the sol-gel method of a series of new hybrid materials prepared by the co-condensation of tetraethoxysilane (TEOS) and 4-chlorophenyltriethoxysilane (ClPhTEOS) in different molar ratios is described. The aim of the study is not only the preparation of new materials but also their characterization by means of different techniques (FT-IR, 29Si NMR, X-ray Diffraction, and N2/CO2 adsorption, among others) to obtain information on their chemical behavior and porous structure. Understanding how the chemical and textural properties of these materials are modulated with respect to the molar percentage of organic precursor will help to envisage their possible applications: From the most conventional such as catalysis, adsorption, or separation, to the most advanced in nanotechnology such as microelectronics, photoluminescence, non-linear optics, or sensorics., This research was funded by “Ministerio de Ciencia e Innovación” (Project ref. PID2020-113558RB-C42).

The narrative of a line of research from a feminist perspective involves describing the
situated practices that contribute to understanding inequality in the construction of the social relationships that build links between human and nonhuman materialities. This paper aims to link
feminist epistemology and actor–network theory to the expert network that produces, sustains and
manages the design of the chemical zone of a fiber optic sensor (FOS) and of new smart materials,
tracing the path of a university research group with important scientific publications that has also
developed a line of work in the field of science, technology and society (STS). We are interested in
the generalized division of labor and the role of science and technology in the creation of symbols in
our culture, particularly in the field of expert knowledge, where research carried out by men and
women constructs trajectories of academic success that are predominantly male. The transversal
incorporation of gender analysis into the production of FOSs helps reveal the processes that have, up
to this point, excluded women from prominent positions in publications. © 2022 by the authors., Research under the projects “Fiber optic chemical sensors for catalytic reactor monitoring”
(MAT2016-78155-C2-2-R) and “Multifuncionality in nanostructures silicon bases hybrid xerogels with
lanthanide and titanium dopands: from fiber optic sensors to solar cell devices” (PID2020-113558
RB-C42), funded by the Spanish Ministry of Science and Innovation.

This work provides insight into the correlation between the luminescent response of a water-vapour optical fibre sensor and the textural properties of its lanthanide-doped silica coating. To this end, a library of 16 silica xerogels derived from combinations between 2 lanthanide dopants (EuIII, TbIII) and 8 antenna ligands was synthesised and characterised by photoluminescence spectroscopy and N2 and CO2 adsorption-desorption isotherms, among others. Based on the best luminescent response and most-suited porous texture, the material doped with TbIII and 2,2′-(4-(2-Ethoxyethoxy)pyridine-2,6-diyl)bis(4,5-dihydrooxazole) was selected to construct the probe. A film of this material was affixed to a commercial silica fibre by dip-coating and the resulting sensor was tested in a climatic chamber with relative humidity ranging from 20 to 90% to obtain normalised time-response and calibration curves at three temperatures. The response was linear up to certain water-vapour concentrations, beyond which abruptly changed to polynomial, acting against the sensor resolution. The adsorption mechanism was elucidated by comparing the isosteric enthalpies of adsorption calculated from the sensor calibration curves to those determined from the monolith water-vapour isotherms, revealing that capillary condensation in the membrane mesopores was the key phenomenon leading to the response deviating from linearity., Spanish Ministerio de Ciencia e Innovación (MICINN) and Agencia Estatal de Investigación (AEI): grant numbers PID2020-113558RB-C42 and PID2019-106070RB-I00. Open access funding provided by Universidad Pública de Navarra.

This work exemplifies how incorporating organosilane modifiers into silica matrices allows for tuning the optical response of reflection photonic sensors through customizing the textural properties of hybrid xerogel sensing films. Xerogels with propyl molar percentages 0, 5, and 10% are used to construct photonic probes (OFS0pTEOS, OFS5pTEOS and OFS10pTEOS, respectively) by dip-coating upon optimizing film deposition parameters. The time response of these probes toward a battery of volatile organic compounds (VOCs) comprising species with different functionality, size-shape, and polarity is systematically analyzed through ON/OFF experiments, revealing that a low propyl content makes the poor-responding OFS0pTEOS film highly sensitive toward non-aromatic, large molecules with low-polar or non-polar character in OFS5pTEOS. This sensor is particularly sensitive toward alkanes, with globular cyclohexane (cyHex) outperforming elongated n-hexane. Variable-temperature calibration curves obtained from step-by-step experiments and adsorption-desorption cycles corroborate these observations and allow hysteresis to be quantified. The response to cyHex closely follows VOC concentration changes with the most stable signal among analytes, leading to well-defined curves with low-to-negligible hysteresis. The isosteric enthalpies of cyHex adsorption are obtained for both the bulk material and the sensor, demonstrating labile adsorbate-adsorbent interactions ruling the sensor response and becoming more exothermic for larger VOC concentrations., This work was funded by the Spanish Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (grant numbers PID2020-113558RBC42 and PID2022-137437OB-I00). The authors thank UCTAI (UPNA) for technical support and Dr. A. Ozcáriz for ellipsometry measurements. Open access funding provided by Universidad Pública de Navarra.