Bio
Luís M. N. B. F. Santos (Luis Belchior Santos). Completed the PhD in Chemistry in 1996 by University of Porto, Faculty of Science and the degree in Chemistry in 1987 by Faculty of Science University of Porto. Is Associate Professor (with Habilitation) in the Faculty of Science of the University of Porto (Physical-Chemistry Group at the Department of Chemistry and Biochemistry). Leader of the NSO (Nanostructure and Self Organization) research group at CIQUP | IMS Institute for Molecular Sciences (Associated Laboratory /FCT) . Participates and/or participated as Invited Scientist Fellow In the MPI-PKS Max Planck Institut in Dresden Germany. Works in the area(s) of Science and Chemical Engineering with emphasis on Physical Chemistry and Materials Science. Is internationally recognized for his work in the field of molecular energetics, in the study of thermophysical properties of materials, in particular for his contribution to the interpretation of nanostructuration in ionic liquids. He is also recognized for his studies and developments in the field of new experimental methodologies in the areas of calorimetry, thermophysics and thermoanalysis. Published 213 articles in journals. Has 2 book(s). Has received 5 awards and/or honors. Successful supervision of 8 PhD students. Some CV indicators: H=45; H100=22; > 8250 citations | (Jan 2024). In their professional activities interacted with 213 collaborator(s) co-authorship of scientific papers. Chairman & Organizer of ECTP 2014 - European Conference on Thermophysical Properties. Organizer and Chair of ILWS2017 winter school on ionic liquids. Is Chair of the ILMAT2023 | 7th International Conference on Ionic Liquid-Based Materials. SPERTUS.Porto (2022) Energy Transition and Industrial Competitiveness; iCERR |WorkSHOP on Science Education Innovation (2023).
Since October of 2023 is Director of the CIQUP | Research Center in Chemistry (Centro de Investigação em Química da Universidade do Porto). Education Innovation (2023).
Since October of 2023 is Director of the CIQUP | Research Center in Chemistry (Centro de Investigação em Química da Universidade do Porto). Education Innovation (2023).
CIQUP | Centro de Investigação em Química (FCUP)
IMS | Institute of Molecular Sciences
https://www.fc.up.pt/ciqup/
https://www.fc.up.pt/ciqup/
ORCID: http://orcid.org/0000-0003-3040-0358
CIENCIA ID: https://www.cienciavitae.pt/en/0816-D726-42A2
Publications
Showing 5 latest publications. Total publications: 236
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1.
Exploration of the anion effect on the electrical conductivity of ionic liquids,
in Journal of Molecular Liquids, 2025, ISSN: 0167-7322, Volume: 423,
Article, Indexed in: crossref, scopus DOI: 10.1016/j.molliq.2025.126916
P-017-VJZ
Article, Indexed in: crossref, scopus DOI: 10.1016/j.molliq.2025.126916
P-017-VJZ
Abstract
The effect of the anion on the electrical conductivity of ionic liquids was explored by a high-precision study of the temperature dependence (283–333 K) of the electrical conductivity of ten ILs based on the 1-butyl-3-methylimidazolium cation, [C4C1im]+. The following trend was observed for the molar conductivity at the reference temperature of 298.15 K: Ac < PF6− < BETI < OTf < TFA < BF4− < FAP < NTf2 < FSI < DCA. The molar conductivity at infinite temperature, AΛ, and the energy barrier, EΛ, derived from the Vogel–Fulcher–Tammann equation (VFT) fitting were found to correlate well with the shape/size/dynamics and cohesive energy/charge localization of the studied ions. An extensive revision and comparison with the available experimental electrical conductivity data for the studied ionic liquids is also presented. Additionally, this work presents a detailed description, testing, and evaluation of performance results of a new system/methodology for the high-precision measurement of the electrical conductivity of ionic fluids, designed to minimize the size of the ionic liquid sample and in situ degassing of the sample. The measuring system is based on a high-precision LCR meter and a conductivity cell system designed to ensure the vacuum and gastightness of the sample container. The high-precision temperature control is ensured by a customized thermal chamber based on a heating and cooling Peltier system. The electrical conductivity data were corrected for the effect of solution polarization by extrapolating the resistance to infinite frequency. The accuracy and resolution of the system were evaluated by measuring the conductivity of the reference ionic liquid, [C6C1im][NTf2] which was found to be in excellent agreement with the recommended data. © 2025 The Author(s)
2.
Giant Growth of Crystalline Films of 1,3,5-Tris(N-carbazolyl)benzene (TCB) and 1,3,5-Tris(diphenylamino)benzene (TDAB) on Engineered Shapes of Ionic Liquid in Vacuum,
in CRYSTAL GROWTH & DESIGN, 2025, ISSN: 1528-7483, Volume: 25,
Article, Indexed in: crossref, scopus, wos DOI: 10.1021/acs.cgd.4c01355
P-017-Z34
Article, Indexed in: crossref, scopus, wos DOI: 10.1021/acs.cgd.4c01355
P-017-Z34
Abstract
This study demonstrates the efficacy of ionic liquid (IL)-assisted vapor deposition in achieving high-quality and distinctive crystal film growth of two organic semiconductors (OSCs): a carbazole derivative (TCB) and a phenylamine derivative (TDAB). ILs with different wetting properties (short-chain [C2C1im][NTf2] and long-chain [C8C1im][NTf2]) and engineered shapes (microdroplets and coalesced film) were utilized as solvents in a vacuum. Through a meticulously designed experimental strategy, encompassing both sequential and simultaneous deposition of the IL and the OSC, this study unveils the pivotal role of ILs in shaping the crystallization behavior of the organic compound. Differential scanning calorimetry, polarized light microscopy, high-resolution scanning electron microscopy, and X-ray diffraction were employed for the films' thermal, morphological, and structural characterization. Thin films of TDAB exhibit crystallinity and a greater tendency to grow tridimensionally, forming giant pillars. However, the typical vertical growth of TDAB on solid substrates is altered when deposition occurs on surfaces coated with ILs. The IL promotes the lateral growth of nanostructures. The experimental results reveal variations in film morphology and coverage influenced by the cation alkyl chain length of the IL. In contrast to TDAB, TCB films are amorphous when thermally evaporated on solid substrates. Notably, IL-assisted vapor deposition induces the crystallization of TCB. Furthermore, TCB films deposited on coalesced IL films exhibit enhanced crystallinity and homogeneous horizontal growth, representing a significant finding in the context of thin film deposition and semiconductor device fabrication.
3.
Tailoring Morphology and Wetting Behavior of Films of Ionic Liquid Mixtures,
in LANGMUIR, 2025, ISSN: 0743-7463, Volume: 41,
Article, Indexed in: crossref, scopus, wos DOI: 10.1021/acs.langmuir.5c00653
P-018-FZJ
Article, Indexed in: crossref, scopus, wos DOI: 10.1021/acs.langmuir.5c00653
P-018-FZJ
Abstract
Extensive research has focused on films formed by pure ionic liquids (ILs). However, growing interest in IL mixtures and their synergistic properties presents new opportunities for targeted applications and fundamental scientific investigations. This study explores the morphology of films composed of mixtures of two ILs, [C2C1im][OTf] and [C8C1im][OTf], co-deposited via physical vapor deposition (PVD)/vacuum thermal evaporation. The primary objective was understanding how varying the IL ratio influences droplet formation, surface coverage, and overall film structure. Thin-film growth was examined on glass substrates coated with indium tin oxide (ITO) and ITO/glass surfaces coated with metallic films (Au and Ag). Film morphology was characterized using optical and high-resolution scanning electron microscopy (SEM), while elemental composition was analyzed via X-ray photoelectron spectroscopy (XPS). The results show that IL mixture morphology is strongly influenced by both IL composition and substrate type. Increasing [C8C1im][OTf] content led to larger microstructures due to improved wetting, particularly on Au surfaces, resulting in nearly fully coalesced films. Metallic surfaces near ITO significantly impacted droplet behavior, with ILs exhibiting a strong affinity for metals, especially when the long-chain IL dominated the mixture. The IL-assisted crystallization of rubrene, a high-performance organic semiconductor (OSC) that typically exhibits poor crystallinity when deposited via PVD, highlights the potential of IL mixtures to enhance organic film quality. X-ray diffraction (XRD) confirmed that [C2C1im][OTf] and [C8C1im][OTf] mixtures significantly improved rubrene crystallinity, demonstrating their potential to create an optimal environment for OSC solubility and crystallization.
4.
Tailoring Morphology and Wetting Behavior of Films of Ionic Liquid Mixtures,
in Langmuir, 2025, ISSN: 0743-7463, Volume: 41,
Article, Indexed in: scopus DOI: 10.1021/acs.langmuir.5c00653
P-018-JF8
Article, Indexed in: scopus DOI: 10.1021/acs.langmuir.5c00653
P-018-JF8
Abstract
Extensive research has focused on films formed by pure ionic liquids (ILs). However, growing interest in IL mixtures and their synergistic properties presents new opportunities for targeted applications and fundamental scientific investigations. This study explores the morphology of films composed of mixtures of two ILs, [C2C1im][OTf] and [C8C1im][OTf], co-deposited via physical vapor deposition (PVD)/vacuum thermal evaporation. The primary objective was understanding how varying the IL ratio influences droplet formation, surface coverage, and overall film structure. Thin-film growth was examined on glass substrates coated with indium tin oxide (ITO) and ITO/glass surfaces coated with metallic films (Au and Ag). Film morphology was characterized using optical and high-resolution scanning electron microscopy (SEM), while elemental composition was analyzed via X-ray photoelectron spectroscopy (XPS). The results show that IL mixture morphology is strongly influenced by both IL composition and substrate type. Increasing [C8C1im][OTf] content led to larger microstructures due to improved wetting, particularly on Au surfaces, resulting in nearly fully coalesced films. Metallic surfaces near ITO significantly impacted droplet behavior, with ILs exhibiting a strong affinity for metals, especially when the long-chain IL dominated the mixture. The IL-assisted crystallization of rubrene, a high-performance organic semiconductor (OSC) that typically exhibits poor crystallinity when deposited via PVD, highlights the potential of IL mixtures to enhance organic film quality. X-ray diffraction (XRD) confirmed that [C2C1im][OTf] and [C8C1im][OTf] mixtures significantly improved rubrene crystallinity, demonstrating their potential to create an optimal environment for OSC solubility and crystallization. © 2025 American Chemical Society.
5.
Impact of nanostructuration on the transport properties of ionic liquids,
in FLUID PHASE EQUILIBRIA, 2025, ISSN: 0378-3812, Volume: 597,
Article, Indexed in: crossref, scopus, wos DOI: 10.1016/j.fluid.2025.114458
P-018-T11
Article, Indexed in: crossref, scopus, wos DOI: 10.1016/j.fluid.2025.114458
P-018-T11
Abstract
The impact of nanostructuration on the transport properties of ionic liquids (ILs) was explored by a systematic and high-resolution study of the temperature dependence of the viscosity and electrical conductivity of seven ILs homolog series: [C(n)C(1)im]BF4, [C(n)C(1)im]PF6, [C(n)C(1)im][OTf], [C(n)C(1)im][FAP], [C(n)C(1)im][NTf2], [CnC(1)pyr][NTf2], [Cnpy][NTf2]. The increase of the alkyl chain length was found to increase the viscosity and decrease the molar conductivity due to a reduction of the overall mobility of the liquid and enhancement of the van der Waals interactions. The temperature dependency of transport properties was fitted to the Vogel-Fulcher-Tammann equation (VFT), and the energy barrier and pre-exponential coefficients were derived. The obtained results highlight the trendshift (n = 6-7) in the profile of the transport properties, which is a reflection of the intensification of nanostructuration and describes the transition from a liquid with a strong ionic character to a nanostructured liquid dominated by the hydrophobic domain. The derived energy barriers were found to correspond to around 0.2-0.35 of the cohesive interactions of the ionic liquids, with the spherical anions BF4- and PF6- showing a higher fraction than the more stretched and larger anions, such as NTf2. This fraction was found to not be affected by the alkyl chain length. The increase of the nonpolar region was also reflected in a more pronounced deviation from the ideal Walden relation. This highlights the increased complexity of the electric conductivity when compared with viscosity due to the heterogeneity of charge distribution, revealing the impact of ionic surface-volume ratio and anion-cation size ratio.