Degree: Habilitation




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).

CIQUP  |  Centro de Investigação em Química (FCUP) 
IMS |  Institute of Molecular Sciences

SCOPUS, Author ID: 7202567010



Showing 5 latest publications. Total publications: 226
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1. The effect of ionic liquids on the nucleation and growth of perylene films obtained by vapor deposition, Costa, JCS; Campos, RM; Castro, ACM; Farinha, AFM; Oliveira, GNP; Araújo, JP; Santos, LMNBF in CRYSTENGCOMM, 2023, ISSN: 1466-8033,  Volume: 25, 
Article,  Indexed in: crossref, scopus, unpaywall, wos  DOI: 10.1039/d2ce01495e P-00X-REB
Abstract Microdroplets and thin films of imidazolium-based ionic liquids (ILs) of different sizes and shapes were used as confining agents for the formation of high-quality perylene crystals by vapor deposition. The role of ILs to control the nucleation and subsequent crystal growth of perylene was investigated by sequential and simultaneous depositions of both materials using indium tin oxide (ITO) as the underlying substrate. The deposition of ILs onto the perylene film surface led to the formation of a complete 2D wetting layer, followed by island growth. Higher adhesion and affinity were found for longer-chain ILs. Inverting the deposition order, the perylene microcrystals were found to grow via the ILs droplets. Additionally, the nucleation and growth of perylene monocrystals enhanced the coalescence mechanisms of the ILs droplets. This wetting process was especially evident for longer-chain ILs. The deposition of perylene onto ITO surfaces fully covered with coalesced ionic liquid films led to the formation of a perylene film with the highest homogeneity as the result of a decrease in surface mobility. The co-deposition of perylene and ILs emphasized the potential application of ILs as crystallization solvents for the formation of thin organic films with improved crystalline quality without compromising the optoelectronic properties.

2. Influence of the Deposition Rate and Substrate Temperature on the Morphology of Thermally Evaporated Ionic Liquids, Carvalho, RM; Neto, C; Santos, LMNBF Bastos, M; Costa, JCS in FLUIDS, 2023, ISSN: 2311-5521,  Volume: 8, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.3390/fluids8030105 P-00Y-5DQ
Abstract The wetting behavior of ionic liquids (ILs) on the mesoscopic scale considerably impacts a wide range of scientific fields and technologies. Particularly under vacuum conditions, these materials exhibit unique characteristics. This work explores the effect of the deposition rate and substrate temperature on the nucleation, droplet formation, and droplet spreading of ILs films obtained by thermal evaporation. Four ILs were studied, encompassing an alkylimidazolium cation (C(n)C(1)im) and either bis(trifluoromethylsulfonyl)imide (NTf2) or the triflate (OTf) as the anion. Each IL sample was simultaneously deposited on surfaces of indium tin oxide (ITO) and silver (Ag). The mass flow rate was reproducibly controlled using a Knudsen cell as an evaporation source, and the film morphology (micro- and nanodroplets) was evaluated by scanning electron microscopy (SEM). The wettability of the substrates by the ILs was notably affected by changes in mass flow rate and substrate temperature. Specifically, the results indicated that an increase in the deposition rate and/or substrate temperature intensified the droplet coalescence of [C(2)C(1)im][NTf2] and [C(2)C(1)im][OTf] on ITO surfaces. Conversely, a smaller impact was observed on the Ag surface due to the strong adhesion between the ILs and the metallic film. Furthermore, modifying the deposition parameters resulted in a noticeable differentiation in the droplet morphology obtained for [C(8)C(1)im][NTf2] and [C(8)C(1)im][OTf]. Nevertheless, droplets from long-chain ILs deposited on ITO surfaces showed intensified coalescence, regardless of the deposition rate or substrate temperature.

3. Confined Silver Nanoparticles in Ionic Liquid Films, Alves, ACPM; Santos, LMNBF Bastos, M; Costa, JCS in MOLECULES, 2023, ISSN: 1420-3049,  Volume: 28, 
Article,  Indexed in: crossref, scopus, unpaywall, wos  DOI: 10.3390/molecules28073029 P-00Y-5FQ
Abstract This work reports the formation of silver nanoparticles (AgNPs) by sputter deposition in thin films of three different ionic liquids (ILs) with the same anion (bis(trifluoromethylsulfonyl)imide) and cation (imidazolium), but with different alkyl chain lengths and symmetries in the cationic moiety ([C(4)C(1)im][NTf2], [C(2)C(2)im][NTf2], and [C(5)C(5)im][NTf2]). Ionic liquid (IL) films in the form of microdroplets with different thicknesses (200 to 800 monolayers) were obtained through vacuum thermal evaporation onto glass substrates coated with indium tin oxide (ITO). The sputtering process of the Ag onto the ILs when conducted simultaneously with argon plasma promoted the coalescence of the ILs' droplets and the formation, incorporation, and stabilization of the metallic nanoparticles in the coalesced IL films. The formation/stabilization of the AgNPs in the IL films was confirmed using high-resolution scanning electron microscopy (SEM) and UV-Vis spectroscopy. It was found that the IL films with larger thicknesses (600 and 800 monolayers) were better media for the formation of AgNPs. Among the ILs used, [C(5)C(5)im][NTf2] was found to be particularly promising for the stabilization of AgNPs. The use of larger IL droplets as capture media was found to promote a better stabilization of the AgNPs, thereby reducing their tendency to aggregate.

4. Decomposition of solid C60-indene adducts by retro Diels Alder reaction-A kinetic and thermodynamic study, Rodrigues, DJL; Pina, IBOM; Santos, LMNBF Lima, CFRAC in DIAMOND AND RELATED MATERIALS, 2023, ISSN: 0925-9635,  Volume: 136, 
Article,  Indexed in: scopus, wos  DOI: 10.1016/j.diamond.2023.110031 P-00Y-GHZ
Abstract Diels-Alder cycloaddition is a common synthetic approach to functionalize fullerenes. However, the stability of such fullerene adducts is hampered by the existence of the Retro Diels-Alder (RDA) reaction. Herein, the RDA reactions in the solid phase of the mono and bisadducts of C60 with indene, IC60MA and IC60BA, were studied by differential scanning calorimetry and thermogravimetric analysis. The RDA reaction in solid IC60MA occurs at a higher temperature than in IC60BA. IC60MA decomposition follows a first-order rate law and in IC60BA it is described by two consecutive first-order reaction steps. The decomposition of both adducts yields a metastable C60 solid. The higher decomposition temperature of IC60MA is due to higher activation energy, Ea, and lower preexponential factor, A. The values of Ea for the RDA reactions differ due to crystal packing efficiency in the solids. The measured A values were found to reflect the statistical weight of C60-Indene bonds that can be broken. A reaction mechanism was proposed for the decomposition of the fullerene adducts. The enthalpies of sublimation of IC60MA and IC60BA were estimated based on the enthalpies of their respective RDA reactions. Additionally, the heat capacities of the solid fullerenes (C60, IC60MA, and IC60BA), at T = 298.15 K, were measured by highprecision heat capacity drop calorimetry, indicating that the rotational motion of C60 in the crystal increases its expected heat capacity.

5. How great is the stabilization of crowded polyphenylbiphenyls by London dispersion?, Lima, CRAC; Mague, JT; Du, YC; Pascal, RA; Santos, LMNBF in PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2023, ISSN: 1463-9076,  Volume: 25, 
Article,  Indexed in: scopus, wos  DOI: 10.1039/d2cp05085d P-00Y-CSB
Abstract Decaphenylbiphenyl (1) and 2,2',4,4',6,6'-hexaphenylbiphenyl (2) are bulky molecules expected to be greatly destabilized by steric crowding. Herein, through a combined experimental and computational approach, we evaluate the molecular energetics of crowded biphenyls. This is complemented by the study of phase equilibria for 1 and 2. Compound 1 shows a rich phase behavior, displaying an unusual interconversion between two polymorphs. Surprisingly, the polymorph with distorted molecules of C-1 symmetry is found to have the highest melting point and to be the one that is preferentially formed. The thermodynamic results also indicate that the polymorph displaying the more regular D-2 molecular geometry has larger heat capacity and is probably the more stable at lower temperatures. The melting and sublimation data clearly reveal the weakening of cohesive forces in crowded biphenyls due to the lower molecular surface area. The experimental quantification of the intramolecular interactions in 1 and 2 indicated, using homodesmotic reactions, a molecular stabilization of about 30 kJ mol(-1). We attribute the origin of this stabilization in both compounds to the existence of two parallel-displaced pMIDLINE HORIZONTAL ELLIPSISp interactions between the ortho-phenyl substituents on each side of the central biphenyl. Computational calculations with dispersion-corrected DFT methods underestimate the stabilization in 1, unless the steric crowding is well balanced in a homodesmotic scheme. This work demonstrates that London dispersion forces are important in crowded aromatic systems, making these molecules considerably more stable than previously thought.