Dear Colleagues,

Self-assembly in chemistry has recently gained increasing attention due to its consequences with regard to developing novel materials. From a scientific point of view, the composition, intermolecular interactions, and chemical stability are pivotal factors in determining the properties of self-assembled structures. From a technological point of view, they are involved in drug delivery, nanoparticle synthesis, liquid crystals, and in several other state-of-the-art applications. Interest is also focused on self-assembly triggered by external fields (electrorheology, magnetorheology) or factors/conditions (smart materials).

The main focus of this Special Issue will be to point out the recent research progress on self-assembly in chemistry and supra-molecular chemistry. Interest in nano- and meso-structures from both the theoretical and experimental point of view is necessary to form a common language and knowledge basis for the scientific community. This Special Issue will be an international platform to synergically present the results of the most exciting experimental and theoretical studies in this field. Research articles, with a special emphasis on results obtained in the last five years, are welcome, as well as review articles on emerging fields and commentaries. Potential topics include, but are not limited to:

• Stabilizing agents
• Reactive and compartmentalizing media for nanoparticle synthesis
• Nanoparticles
• Nanostructures
• Liquid crystals
• Liquid membranes
• Novel applications in chemistry
• Modeling and simulation of structure–properties
• Supramolecular ordering
• Drug and gene delivery
• Computational structure optimisation
• Smart materials
• Ferrofluidics
• Magnetorheology
• Electrorheology
• Amphiphiles
• Complex systems

Dr. Pietro Calandra
Dr. Mikolaj Pochylskj
Dr. Elisabeta Ildyko Szerb
Dr. Domenico Lombardo
Guest Editors

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• Self-assembly
• Supramolecular chemistry
• Surfactants
• Liquid crystals
• Drug delivery
• Nanostructures

Title: Molecular assembling in mixtures of ionic liquids and water
Authors: O. Palumboa, F. Trequattrinib, J.-B. Brubachc, P. Royc, A. Paolonea
Affiliation: a Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, UOS La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy ([email protected]) b Department of Physics, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Roma, Italy c Synchrotron SOLEIL, 91192 Gif Sur Yvette, France
Abstract: The charming properties that have made ionic liquids so interesting lie in the possibility of tailoring them by means of a proper choice of either the cation or the anion or by mixing with other liquids, such as water, alcohols or different ILs [1]. A deep understanding of their microscopic properties and of the assembling of ions in mixed systems is fundamental in order to master such possibility. The combined use of vibrational spectroscopies measurements and ab-initio calculations is a powerful tool to obtain information about the microscopic configurations [1-3] and about the phase transitions and the kind of interactions occurring in the system, which determinate the structure and the properties of ILs. In this study we compare the effects of water on the phase diagram of the hydrophilic 1-butyl-1-methylpyrrolidinium dicyanamide ionic liquid from room temperature down to 140 K, with a special attention to the changes of the environment of water molecules and the interface between water and ionic liquid. Combined infrared spectroscopy and ab-initio calculations provide information about the phase transitions and the intermolecular changes occurring in the liquid. The temperature dependence of the mid-infrared spectrum in the temperature range between 140 and 330 K indicates that in the ionic liquid containing only a small quantity of water due to absorption from the atmosphere, a cold crystallization takes place on heating between ≈240 and ≈260 K, that is suppressed when water is intentionally added in a greater amount. The analysis of the O-H stretching bands indicates the existence of two different “liquid like” water environments. When cold crystallization takes places the water molecules, which seem less coordinated to the other H2O molecules and more related to the anions, appear to be part of the crystallized sample. In both cases, it seems that at microscopic level the sample is not homogeneous, but more likely it is composed of separated clusters or regions of bulk water confined in the ionic liquid. These effects strongly resemble and further corroborate those already observed in the hydrophilic 1-butyl-1-methylimidazolium dicyanamide ionic liquid.[3]

Title: Thermal investigations on innovative nanostructured systems by FTIR spectroscopy
Authors: M. T. Caccamo, S. Magazù
Affiliation: Department of Mathematical and Informatics Sciences, Physical Sciences and Earth Sciences, Messina University, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Abstract: The paper reports a study on concentrated trehalose aqueous solutions which are attracting a great interest both for the scientific point of view and for the practical applications. In particular, despite the extraordinary bioprotective and osmoregulative properties of trehalose are well empirically defined, the underlying molecular mechanisms remain cryptic. It is known that to understand such mechanisms determining the effectiveness of trehalose, it is critical to characterize the structural and dynamical properties of disaccharide water solutions. In this context, the combination of acoustic levitation and InfraRed (IR) spectroscopy techniques offers a method to check the dehydration process of the diluted trehalose mixtures as a function of time and of the high concentration range. The levitated samples are analyzed by means of IR spectroscopy and the spectral data are processed by wavelet cross-correlation analysis.

Title: A comparative study of absorption spectra and photoelectrochemical properties of hybrid-organic and donor-acceptor dyes as supramolecular sensitizers for dye-sensitized solar cells.
Authors: S. Gullacea,b, G. Calogeroa, A. Bartolottaa.
Affiliation: a CNR-IPCF, Istituto per i Processi Chimico-Fisici, via F. Stagno D’Alcontres 37, I-98158 Messina, Italy. b Università di Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Abstract: Here we studied and compared the sensitizing properties of two different hybrid-organic dyes, for photovoltaic applications in Grätzel cells. The first studied is the compound called C106 (NaRu (4,4'-bis (5- (hexylthio) thiophen-2- yl) -2,2'-bipyridine) (4-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(NCS)2), while the second one is called Y123 (3- {6- {4- [bis (2 ', 4'-dihexyloxybiphenyl- 4-yl) amino-] phenyl} -4,4-dihexyl-cyclopenta- [2,1-b: 3,4-b] dithiphene-2-yl} -2-cyanoacrylic acid), is an organic dye free from central metal with a high molar extinction coefficient (ɛ) which makes it particularly interesting to be used in thin films of TiO2. The analysis of the absorption spectra of the Y123 photoanode shows two absorption maxima one at 401 nm and the other 541nm which, and despite the highest molar extinction coefficient, it exhibits lower intensity values than those of photoanodes with C106. Nevertheless, the photoelectrochemical performances of the two dyes when their cells are compared, employing a black background, are similar. We found that only employing a white background for the cells in the case of the Y123 dye a substantial increase in current produced and efficiency (+ 113% and +101 respectively) is observed.)

Title: Superhydrophobic self-assembled silane monolayers on etched 6082 Aluminium alloy for anti-corrosion applications
Authors: A. Khaskoussia, L. Calabreseb, E. Proverbiob
Affiliation: a National Interuniversity Consortium of Materials Science and Technology, INSTM, Via Giuseppe Giusti 9, 50121 Firenze, Italy ([email protected]) b Department of Engineering, University of Messina, Contrada di Dio Sant’Agata, 98166 Messina, Italy
Abstract: Super-hydrophobicity is one of the highly required surface properties for several industrial applications for which specific surface properties are required (such as self-cleaning, antifreeze, anti-adhesion or anti-corrosion applications). In such a context, in the recent years different approaches have been proposed aimed at obtaining super-hydrophobic hierarchical surfaces inspired by nature. Thanks to the opportunity to limit significantly the surface interaction between the liquids and the metallic support, the super-hydrophobic surfaces represent potential effective approaches to enhance the corrosion resistance of materials usually sensitive to corrosion degradation. However, usually the proposed approaches require complex synthesis processes and production technologies that are not easily scalable. In this paper a two-stage approach to obtain super-hydrophobic surfaces inspired by nature was proposed: 1) surface texturing: by using three short-term treatment with i) boiling water, ii) HF/HCl etching or iii) concentrated HNO3/HCl solution 2) Self-assembled silane monolayers: a thin layer of octadecylsilane was applied by dip-coating of diluted sol-gel solution and following polymerization for 3 hours at 100 °C in an oven to complete the low surface energy polymer curing. EN AW-6082 T6 aluminium alloy was used as substrate for the sample preparation. The proposed sol-gel self-assembling approach of silane layer not significantly modified the hierarchical microstructure of the etched aluminium substrate. The surface morphology of all three approaches is structured by a peculiar dual hierarchical nano-/micro-roughness profile. Furthermore, the sessile drop tests evidenced that the water contact angles ranged from 160° to nearly 180°. High water contact angle, above 175°, was evidenced for HF/HCl etched silanized surface. The results evidenced that he hydrophobic behavior of the aluminum surface can designed coupling different etching treatment (tailoring a peculiar micro-nano roughness profile) with a self-assembled silane monolayer deposition (to reduce surface energy). These results are promising for further development to better assess the relationship among hierarchical morphology, super-hydrophobicity and anti-corrosion performances.

Title: Novel methods to prepare ionic liquids. Last five years
Authors: L. Maiuoloa, D. Lombardob, E. Szerbc, M. Pochylskid, P. Calandrae
Affiliation: a Università della Calabria, Cosenza, Italy b Consiglio Nazionale delle Ricerche, Istituto Processi Chimico-Fisici, (CNR–IPCF), 98158 Messina, Italy c“Coriolan Dragulescu” Institute of Chemistry, Timisoara, Romania d Faculty of Physics, Adam Mickiewicz University, Wieniawskiego 1, 61-712 Poznań, Poland e Consiglio Nazionale delle Ricerche - Istituto per lo Studio dei Sistemi Nanostrutturati, Rome, Italy
Abstract: Ionic liquid (ILs), also called liquid electrolytes, ionic melts, ionic fluids, fused salts, liquid salts, or ionic glasses, are salts in the liquid state at a some arbitrary temperature, usually close to room temperature. So, they are largely made of ions and short-living ion pairs. The variable combination of cation and ion has an high impact on polarity, hydrophilicity/hydrophobicity and chemical-physical properties of ionic liquids, including their melting points. From the structural point of view, they are low-vapor-pressure strongly interacting fluids with an order extending to medium range (ionic self-assembly) as a consequence of strong electrostatic interactions. This scenario is further enriched by hydrophobic, steric and π–π interactions conferring complex behaviour to such systems. From the applicative point of view these substances materials are used for many purposes, from separation/extraction to chemical synthesis, from electric battery applications to green chemistry, prevalently for their appealing possibility of recycling and reusing. Although the term "ionic liquid" in the general sense was used already in the '40s, only recently a steep increase in their use occurred, which has triggered much research efforts for their preparation. This work will review the recent trends (last 5 years) for ionic liquid preparation hoping it will be useful for research facing this exciting field.