Mass transport in polymers

The study of mass transport in polymeric membranes has grown in importance due to its potential application in many processes such as separation of gases and vapors, packaging, controlled drug release. The diffusion of a low molecular weight species in a polymer is often accompanied by other phenomena like swelling, reactions, stresses, that have not been investigated in all their aspects yet. Furthermore, novel materials have been developed that include inorganic fillers, reactive functional groups or ions, that make the scenery even more complicated. The present work focused on the experimental study of systems where the diffusion is accompanied by other processes; suitable models were also developed to describe the particular circumstances in order to understand the underlying concepts and be able to design the performances of the material. The effect of solvent-induced deformation in polymeric films during sorption processes was studied since the dilation, especially in constrained membranes, can cause the development of stresses and therefore early failures of the material. The bending beam technique was used to test the effects of the dilation and the stress induced in the polymer by penetrant diffusion. A model based on the laminate theory was developed that accounts for the swelling and is able to predict the stress that raise in the material. The addition of inorganic fillers affects the transport properties of polymeric films. Mixed matrix membranes based on fluorinated, high free volume matrices show attractive performances for separation purposes but there is a need for deeper investigation of the selectivity properties towards gases and vapors. A new procedure based on the NELF model was tested on the experimental data; it allows to predict solubility of every penetrant on the basis of data for one vapor. The method has proved to be useful also for the determination of the diffusion coefficient and for an estimation of the permeability in the composite materials. Oxygen scavenging systems can overcome lack of barrier properties in common polymers that forbids their application in sensitive applications as food packaging. The final goal of obtaining a membrane almost impermeable to oxygen leads to experimental times out of reach. Hence, a simple model was developed in order to describe the transport of oxygen in a membrane with also reactive groups and analyze the experimental data collected on SBS copolymers that show attractive scavenging capacity. Furthermore, a model for predicting the oxygen barrier behavior of a film formed as a blend of OSP in a common packaging material was built, considering particles capable of reactions with oxygen embedded in a non-reactive matrix. Perfluorosulphonic acid ionomers (PFSI) are capturing attention due to a high thermal and chemical resistance coupled with very peculiar transport properties, that make them appropriate to be used in fuel cells. The possible effect of different formation procedure was studied together with the swelling due to water sorption since both water uptake and dilation can dramatically affect the fuel cells performances. The water diffusion and sorption was studied with a FTIR-ATR spectrometer that can give deeper information on the bonds between water molecules and the sulphonic hydrophilic groups and, therefore, on the microstructure of the hydrated ionomer.

Synthesis and Physical-Chemical characterization of Metallic Nanoparticles

The stabilization of nanoparticles against their irreversible particle aggregation and oxidation reactions. is a requirement for further advancement in nanoparticle science and technology. For this reason the research aim on this topic focuses on the synthesis of various metal nanoparticles protected with monolayers containing different reactive head groups and functional tail groups. In this work cuprous bromide nanocrystals haave been synthetized with a diameter of about 20 nanometers according to a new sybthetic method adding dropwise ascorbic acid to a water solution of lithium bromide and cupric chloride under continuous stirring and nitrogen flux. Butane thiolate Cu protected nanoparticles have been synthetized according to three different syntesys methods. Their morphologies appear related to the physicochemical conditions during the synthesis and to the dispersing medium used to prepare the sample. Synthesis method II allows to obtain stable nanoparticles of 1-2 nm in size both isolated and forming clusters. Nanoparticle cluster formation was enhanced as water was used as dispersing medium probably due to the idrophobic nature of the butanethiolate layers coating the nanoparticle surface. Synthesis methods I and III lead to large unstable spherical nanoparticles with size ranging between 20 to 50 nm. These nanoparticles appeared in the TEM micrograph with the same morphology independently on the dispersing medium used in the sample preparation. The stability and dimensions of the copper nanoparticles appear inversely related. Using the same methods above described for the butanethiolate protected copper nanoparticles 4-methylbenzenethiol protected copper nanoparticles have been prepared. Diffractometric and spectroscopic data reveal that decomposition processes didn’t occur in both the 4-methylbenzenethiol copper protected nanoparticles precipitates from formic acid and from water in a period of time six month long. Se anticarcinogenic effects by multiple mechanisms have been extensively investigated and documented and Se is defined a genuine nutritional cancer-protecting element and a significant protective effect of Se against major forms of cancer. Furthermore phloroglucinol was found to possess cytoprotective effects against oxidative stress, thanks to reactive oxygen species (ROS) which are associated with cells and tissue damages and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. The goal of our work has been to set up a new method to synthesize in mild conditions amorphous Se nanopaticles surface capped with phloroglucinol, which is used during synthesis as reducing agent to obtain stable Se nanoparticles in ethanol, performing the synergies offered by the specific anticarcinogenic properties of Se and the antioxiding ones of phloroalucinol. We have synthesized selenium nanoparticles protected by phenolic molecules chemically bonded to their surface. The phenol molecules coating the nanoparticles surfaces form low ordered arrays as can be seen from the wider shape of the absorptions in the FT-IR spectrum with respect to those appearing in that of crystalline phenol. On the other hand, metallic nanoparticles with unique optical properties, facile surface chemistry and appropriate size scale are generating much enthusiasm in nanomedicine. In fact Au nanoparticles has immense potential for both cancer diagnosis and therapy. Especially Au nanoparticles efficiently convert the strongly adsorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. According to the about, metal nanoparticles-HA nanocrystals composites should have tremendous potential in novel methods for therapy of cancer. 11 mercaptoundecanoic surface protected Au4Ag1 nanoparticles adsorbed on nanometric apathyte crystals we have successfully prepared like an anticancer nanoparticles deliver system utilizing biomimetic hydroxyapatyte nanocrystals as deliver agents. Furthermore natural chrysotile, formed by densely packed bundles of multiwalled hollow nanotubes, is a mineral very suitable for nanowires preparation when their inner nanometer-sized cavity is filled with a proper material. Bundles of chrysotile nanotubes can then behave as host systems, where their large interchannel separation is actually expected to prevent the interaction between individual guest metallic nanoparticles and act as a confining barrier. Chrysotile nanotubes have been filled with molten metals such as Hg, Pb, Sn, semimetals, Bi, Te, Se, and with semiconductor materials such as InSb, CdSe, GaAs, and InP using both high-pressure techniques and metal-organic chemical vapor deposition. Under hydrothermal conditions chrysotile nanocrystals have been synthesized as a single phase and can be utilized as a very suitable for nanowires preparation filling their inner nanometer-sized cavity with metallic nanoparticles. In this research work we have synthesized and characterized Stoichiometric synthetic chrysotile nanotubes have been partially filled with bi and monometallic highly monodispersed nanoparticles with diameters ranging from 1,7 to 5,5 nm depending on the core composition (Au, Au4Ag1, Au1Ag4, Ag). In the case of 4 methylbenzenethiol protected silver nanoparticles, the filling was carried out by convection and capillarity effect at room temperature and pressure using a suitable organic solvent. We have obtained new interesting nanowires constituted of metallic nanoparticles filled in inorganic nanotubes with a inner cavity of 7 nm and an isolating wall with a thick ranging from 7 to 21 nm.

Transcriptional regulation of human mu-opioid receptor gene: functional characterization of activating and inhibitory transcription factors

The organization of the nervous and immune systems is characterized by obvious differences and striking parallels. Both systems need to relay information across very short and very long distances. The nervous system communicates over both long and short ranges primarily by means of more or less hardwired intercellular connections, consisting of axons, dendrites, and synapses. Longrange communication in the immune system occurs mainly via the ordered and guided migration of immune cells and systemically acting soluble factors such as antibodies, cytokines, and chemokines. Its short-range communication either is mediated by locally acting soluble factors or transpires during direct cell–cell contact across specialized areas called “immunological synapses” (Kirschensteiner et al., 2003). These parallels in intercellular communication are complemented by a complex array of factors that induce cell growth and differentiation: these factors in the immune system are called cytokines; in the nervous system, they are called neurotrophic factors. Neither the cytokines nor the neurotrophic factors appear to be completely exclusive to either system (Neumann et al., 2002). In particular, mounting evidence indicates that some of the most potent members of the neurotrophin family, for example, nerve growth factor (NGF) and brainderived neurotrophic factor (BDNF), act on or are produced by immune cells (Kerschensteiner et al., 1999) There are, however, other neurotrophic factors, for example the insulin-like growth factor-1 (IGF-1), that can behave similarly (Kermer et al., 2000). These factors may allow the two systems to “cross-talk” and eventually may provide a molecular explanation for the reports that inflammation after central nervous system (CNS) injury has beneficial effects (Moalem et al., 1999). In order to shed some more light on such a cross-talk, therefore, transcription factors modulating mu-opioid receptor (MOPr) expression in neurons and immune cells are here investigated. More precisely, I focused my attention on IGF-I modulation of MOPr in neurons and T-cell receptor induction of MOPr expression in T-lymphocytes. Three different opioid receptors [mu (MOPr), delta (DOPr), and kappa (KOPr)] belonging to the G-protein coupled receptor super-family have been cloned. They are activated by structurallyrelated exogenous opioids or endogenous opioid peptides, and contribute to the regulation of several functions including pain transmission, respiration, cardiac and gastrointestinal functions, and immune response (Zollner and Stein 2007). MOPr is expressed mainly in the central nervous system where it regulates morphine-induced analgesia, tolerance and dependence (Mayer and Hollt 2006). Recently, induction of MOPr expression in different immune cells induced by cytokines has been reported (Kraus et al., 2001; Kraus et al., 2003). The human mu-opioid receptor gene (OPRM1) promoter is of the TATA-less type and has clusters of potential binding sites for different transcription factors (Law et al. 2004). Several studies, primarily focused on the upstream region of the OPRM1 promoter, have investigated transcriptional regulation of MOPr expression. Presently, however, it is still not completely clear how positive and negative transcription regulators cooperatively coordinate cellor tissue-specific transcription of the OPRM1 gene, and how specific growth factors influence its expression. IGF-I and its receptors are widely distributed throughout the nervous system during development, and their involvement in neurogenesis has been extensively investigated (Arsenijevic et al. 1998; van Golen and Feldman 2000). As previously mentioned, such neurotrophic factors can be also produced and/or act on immune cells (Kerschenseteiner et al., 2003). Most of the physiologic effects of IGF-I are mediated by the type I IGF surface receptor which, after ligand binding-induced autophosphorylation, associates with specific adaptor proteins and activates different second messengers (Bondy and Cheng 2004). These include: phosphatidylinositol 3-kinase, mitogen-activated protein kinase (Vincent and Feldman 2002; Di Toro et al. 2005) and members of the Janus kinase (JAK)/STAT3 signalling pathway (Zong et al. 2000; Yadav et al. 2005). REST plays a complex role in neuronal cells by differentially repressing target gene expression (Lunyak et al. 2004; Coulson 2005; Ballas and Mandel 2005). REST expression decreases during neurogenesis, but has been detected in the adult rat brain (Palm et al. 1998) and is up-regulated in response to global ischemia (Calderone et al. 2003) and induction of epilepsy (Spencer et al. 2006). Thus, the REST concentration seems to influence its function and the expression of neuronal genes, and may have different effects in embryonic and differentiated neurons (Su et al. 2004; Sun et al. 2005). In a previous study, REST was elevated during the early stages of neural induction by IGF-I in neuroblastoma cells. REST may contribute to the down-regulation of genes not yet required by the differentiation program, but its expression decreases after five days of treatment to allow for the acquisition of neural phenotypes. Di Toro et al. proposed a model in which the extent of neurite outgrowth in differentiating neuroblastoma cells was affected by the disappearance of REST (Di Toro et al. 2005). The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. Therefore, in the fist part of this thesis, I investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I upregulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 (STAT3) signaling pathway and this transcription factor, binding to the STAT1/3 DNA element located in the promoter, increases OPRM1 transcription. T-cell receptor (TCR) recognizes peptide antigens displayed in the context of the major histocompatibility complex (MHC) and gives rise to a potent as well as branched intracellular signalling that convert naïve T-cells in mature effectors, thus significantly contributing to the genesis of a specific immune response. In the second part of my work I exposed wild type Jurkat CD4+ T-cells to a mixture of CD3 and CD28 antigens in order to fully activate TCR and study whether its signalling influence OPRM1 expression. Results were that TCR engagement determined a significant induction of OPRM1 expression through the activation of transcription factors AP-1, NF-kB and NFAT. Eventually, I investigated MOPr turnover once it has been expressed on T-cells outer membrane. It turned out that DAMGO induced MOPr internalisation and recycling, whereas morphine did not. Overall, from the data collected in this thesis we can conclude that that a reduction in REST is a critical switch enabling IGF-I to up-regulate human MOPr, helping these findings clarify how human MOPr expression is regulated in neuronal cells, and that TCR engagement up-regulates OPRM1 transcription in T-cells. My results that neurotrophic factors a and TCR engagement, as well as it is reported for cytokines, seem to up-regulate OPRM1 in both neurons and immune cells suggest an important role for MOPr as a molecular bridge between neurons and immune cells; therefore, MOPr could play a key role in the cross-talk between immune system and nervous system and in particular in the balance between pro-inflammatory and pro-nociceptive stimuli and analgesic and neuroprotective effects.

Sviluppo di tecniche di analisi ifenate per la quantificazione di biomarcatori di esposizione a tossici ambientali: gli acidi mercapturici

Human biomonitoring (HBM) is an ideal tool for evaluating toxicant exposure in health risk assessment. Chemical substances or their metabolites related to environmental pollutants can be detected as biomarkers of exposure using a wide variety of biological fluids. Individual exposure to aromatic hydrocarbon compounds (benzene, toluene, and o-xylene –“BTX”) were analysed with a liquid chromatography coupled to electrospray ionisation-mass spectrometry (μHPLC-ESI-MS/MS) method for the simultaneous quantitative detection of the BTX exposure biomarker SPMA, SBMA and o-MBMA in human urine. Urinary S-phenylmercapturic acid (SPMA) is a biomarker proposed by the American Conference of Governmental Industrial Hygienists (ACGIH) for assessing occupational exposure to benzene (Biological Exposure Index of 25 microg/g creatinine). Urinary S-benzylmercapturic (SBMA) and o-methyl S-benzyl mercapturic acid (o-MBMA) are specific toluene and o-xylene metabolites of glutathione detoxicant pathways, proposed as reliable biomarkers of exposure. To this aim a pre-treatment of the urine with solid phase extraction (SPE) and an evaporation step were necessary to concentrate the mercapturic acids before instrumental analysis. A liquid chromatography separation was carried out with a reversed phase capillary column (Synergi 4u Max-RP) using a binary gradient composed of an acquous solution of formic acid 0.07% v/v and methanol. The mercapturic acids were determinated by negative-ion-mass spectrometry and the data were corrected using isotope-labelled analogs as internal standards. The analytical method follows U.S. Food and Drug Administration guidance and was applied to assess exposure to BTX in a group of 396 traffic wardens. The association between biomarker results and individual factors, such as age, sex and tobacco smoke were also investigated. The present work also included improvements in the methods used by modifying various chromatographic parameters and experimental procedures. A partial validation was conducted to evaluate LOD, precision, accuracy, recovery as well as matrix effects. Higher sensitivity will be possible in future biological monitoring programmes, allowing evaluation of very low level of BTX human exposure. Keywords: Human biomonitoring, aromatic hydrocarbons, biomarker of exposure, HPLC-MS/MS.

Cluster-derived Gold/Iron catalysts for environmental applications

During the last years we assisted to an exponential growth of scientific discoveries for catalysis by gold and many applications have been found for Au-based catalysts. In the literature there are several studies concerning the use of gold-based catalysts for environmental applications and good results are reported for the catalytic combustion of different volatile organic compounds (VOCs). Recently it has also been established that gold-based catalysts are potentially capable of being effectively employed in fuel cells in order to remove CO traces by preferential CO oxidation in H2-rich streams. Bi-metallic catalysts have attracted increasing attention because of their markedly different properties from either of the costituent metals, and above all their enhanced catalytic activity, selectivity and stability. In the literature there are several studies demostrating the beneficial effect due to the addition of an iron component to gold supported catalysts in terms of enhanced activity, selectivity, resistence to deactivation and prolonged lifetime of the catalyst. In this work we tried to develop a methodology for the preparation of iron stabilized gold nanoparticles with controlled size and composition, particularly in terms of obtaining an intimate contact between different phases, since it is well known that the catalytic behaviour of multi-component supported catalysts is strongly influenced by the size of the metal particles and by their reciprocal interaction. Ligand stabilized metal clusters, with nanometric dimensions, are possible precursors for the preparation of catalytically active nanoparticles with controlled dimensions and compositions. Among these, metal carbonyl clusters are quite attractive, since they can be prepared with several different sizes and compositions and, moreover, they are decomposed under very mild conditions. A novel preparation method was developed during this thesis for the preparation of iron and gold/iron supported catalysts using bi-metallic carbonyl clusters as precursors of highly dispersed nanoparticles over TiO2 and CeO2, which are widely considered two of the most suitable supports for gold nanoparticles. Au/FeOx catalysts were prepared by employing the bi-metallic carbonyl cluster salts [NEt4]4[Au4Fe4(CO)16] (Fe/Au=1) and [NEt4][AuFe4(CO)16] (Fe/Au=4), and for comparison FeOx samples were prepared by employing the homometallic [NEt4][HFe3(CO)11] cluster. These clusters were prepared by Prof. Longoni research group (Department of Physical and Inorganic Chemistry- University of Bologna). Particular attention was dedicated to the optimization of a suitable thermal treatment in order to achieve, apart from a good Au and Fe metal dispersion, also the formation of appropriate species with good catalytic properties. A deep IR study was carried out in order to understand the physical interaction between clusters and different supports and detect the occurrence of chemical reactions between them at any stage of the preparation. The characterization by BET, XRD, TEM, H2-TPR, ICP-AES and XPS was performed in order to investigate the catalysts properties, whit particular attention to the interaction between Au and Fe and its influence on the catalytic activity. This novel preparation method resulted in small gold metallic nanoparticles surrounded by highly dispersed iron oxide species, essentially in an amorphous phase, on both TiO2 and CeO2. The results presented in this thesis confirmed that FeOx species can stabilize small Au particles, since keeping costant the gold content but introducing a higher iron amount a higher metal dispersion was achieved. Partial encapsulation of gold atoms by iron species was observed since the Au/Fe surface ratio was found much lower than bulk ratio and a strong interaction between gold and oxide species, both of iron oxide and supports, was achieved. The prepared catalysts were tested in the total oxidation of VOCs, using toluene and methanol as probe molecules for aromatics and alchols, respectively, and in the PROX reaction. Different performances were observed on titania and ceria catalysts, on both toluene and methanol combustion. Toluene combustion on titania catalyst was found to be enhanced increasing iron loading while a moderate effect on FeOx-Ti activity was achieved by Au addition. In this case toluene combustion was improved due to a higher oxygen mobility depending on enhanced oxygen activation by FeOx and Au/FeOx dispersed on titania. On the contrary ceria activity was strongly decreased in the presence of FeOx, while the introduction of gold was found to moderate the detrimental effect of iron species. In fact, excellent ceria performances are due to its ability to adsorb toluene and O2. Since toluene activation is the determining factor for its oxidation, the partial coverage of ceria sites, responsible of toluene adsorption, by FeOx species finely dispersed on the surface resulted in worse efficiency in toluene combustion. Better results were obtained for both ceria and titania catalysts on methanol total oxidation. In this case, the performances achieved on differently supported catalysts indicate that the oxygen mobility is the determining factor in this reaction. The introduction of gold on both TiO2 and CeO2 catalysts, lead to a higher oxygen mobility due to the weakening of both Fe-O and Ce-O bonds and consequently to enhanced methanol combustion. The catalytic activity was found to strongly depend on oxygen mobility and followed the same trend observed for catalysts reducibility. Regarding CO PROX reaction, it was observed that Au/FeOx titania catalysts are less active than ceria ones, due to the lower reducibility of titania compared to ceria. In fact the availability of lattice oxygen involved in PROX reaction is much higher in the latter catalysts. However, the CO PROX performances observed for ceria catalysts are not really high compared to data reported in literature, probably due to the very low Au/Fe surface ratio achieved with this preparation method. CO preferential oxidation was found to strongly depend on Au particle size but also on surface oxygen reducibility, depending on the different oxide species which can be formed using different thermal treatment conditions or varying the iron loading over the support.

Design, synthesis and Chemical-physical characterization of photocatalytic inorganic nanocrystals for technological applications

This work was based on the synthesis and characterization of innovative crystals for biomedical and technological applications. Different types of syntheses were developed in order to obtain crystals with high photocatalytic properties. A hydrothermal synthesis was also processed to correlate the chemical-physical characteristics with synthesis parameters obtaining synthesis of nanoparticles of titanium dioxide with different morphology, size and crystalline phase depending on the variation of the synthesis parameters. Also a synthesis in water at 80 °C temperature and low pressure was developed from which anatase containing a small percentage of brookite nanoparticles were obtained, presenting a high photocatalytic activity. These particles have been used to obtain the microcrystals formed by an inorganic core of hydroxyapatite surface covered by TiO2 nanoparticles. Micrometer material with higher photocatalytic has been produced. The same nanoparticles have been functionalized with resorcinol oxidized in order to increase the photocatalytic efficiency. Photodegradation test results have confirmed this increase. Finally, synthetic nanoparticles with a waterless synthesis using formic acid and octanol, through esterification "in situ" were synthesized. Nanoparticles superficially covered by carboxylic residues able to bind a wide range of molecules to obtain further photocatalytic properties were obtained.

Deidrogenazione catalitica di idrocarburi per la produzione di H2 "on-board"

Lo studio della deidrogenazione catalitica di idrocarburi affronta uno dei problemi principali per l'applicazione delle fuel cells in aeromobili. La conversione di miscele di idrocarburi in H2 può essere eseguita in loco, evitando le difficoltà di stoccaggio dell'idrogeno: l'H2 prodotto è privo di CO e CO2 e può essere alimentato direttamente alle celle a combustibile per dare energia ai sistemi ausiliari, mentre i prodotti deidrogenati, mantenendo le loro originali caratteristiche possono essere riutilizzati come carburante. In questo un lavoro è stato effettuato uno studio approfondito sulla deidrogenazione parziale (PDH) di diverse miscele di idrocarburi e carburante avio JetA1 desolforato utilizzando Pt-Sn/Al2O3, con l'obiettivo di mettere in luce i principali parametri (condizioni di reazione e composizione di catalizzatore) coinvolti nel processo di deidrogenazione. Inoltre, la PDH di miscele idrocarburiche e di Jet-A1 ha evidenziato che il problema principale in questa reazione è la disattivazione del catalizzatore, a causa della formazione di residui carboniosi e dell’avvelenamento da zolfo. Il meccanismo di disattivazione da residui carboniosi è stato studiato a fondo, essendo uno dei principali fattori che influenzano la vita del catalizzatore e di conseguenza l'applicabilità processo. Alimentando molecole modello separatamente, è stato possibile discriminare le classi di composti che sono coinvolti principalmente nella produzione di H2 o nell’avvelenamento del catalizzatore. Una riduzione parziale della velocità di disattivazione è stata ottenuta modulando l'acidità del catalizzatore al fine di ottimizzare le condizioni di reazione. I catalizzatori Pt-Sn modificati hanno mostrato ottimi risultati in termini di attività, ma soffrono di una disattivazione rapida in presenza di zolfo. Così, la sfida finale di questa ricerca era sviluppare un sistema catalitico in grado di lavorare in condizioni reali con carburante ad alto tenore di zolfo, in questo campo sono stati studiati due nuove classi di materiali: Ni e Co fosfuri supportati su SiO2 e catalizzatori Pd-Pt/Al2O3.

Non-Covalent Interaction: Revealed by Rotational Spectroscopy

The pulsed jet Fourier transform microwave spectroscopy have been applied to several molecular complexes involving H2O, freons, methane, carboxylic acids, and rare gas. The obtained results showcase the suitability of this technique for studying the intermolecular interactions. The rotational spectra of three water adducts of halogenated organic molecules, i.e. chlorotrifluoroethylene, isoflurane and alfa,alfa,alfa,-trifluoroanisole, have been investigated. It has been found that, the halogenation of the partner molecules definitely changes the way in which water will link to the partner molecule. Quadrupole hyperfine structures and/or the tunneling splittings have been observed in the rotational spectra of difluoromethane-dichloromethane, chlorotrifluorometane-fluoromethane, difluoromethane-formaldehyde and trifluoromethane-benzene. These features have been useful to describe their intermolecular interactions (weak hydrogen bonds or halogen bonds), and to size the potential energy surfaces of their internal motions. The rotational spectrum of pyridine-methane pointed out that methane prefers to locate above the ring and link to pyridine through a C-H•••π weak hydrogen bond, rather than the C-H•••n interaction. This behavior, typical of complexes of pyridine with rare gases, suggests classifying CH4, in relation to its ability to form molecular complexes with aromatic molecules, as a pseudo rare gas. The conformational equilibria of three bi-molecules of carboxylic acids, acrylic acid-trifluoroacetic acid, difluoroacetic acid-formic acid and acrylic acid-fluoroacetic acid have been studied. The increase of the hydrogen bond length upon H→D isotopic substitution (Ubbelohde effect) has been deduced from the elongation of the carboxylic carbons C•••C distance. The van der Waals complex tetrahydrofuran-krypton shows that the systematic doubling of the rotational lines has been attributed to the residual pseudo-rotation of tetrahydrofuran in the complex, based on the values of the Coriolis coupling constants, and on the type (mu_b) of the interstate transitions.