COLLOID CHEMISTRY

Author: CABALEIRO LAGO CELIA.
Year: 2005.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE QUIMICA.
Place of preparation: UNIVERSIDAD DE VIGO.

Summary: The thesis presented seeks to study the effect of colloidal aggregates and cyclodextrins on the reactivity was sutratos organic both in agragados colloidal cycle and dextrins in mixed systems where surfactants and cyclodextrins are present. Besides analyzing the iteration between cyclodextrin and surfactants. The work includes a study of the association between ciclosextrinas (CD) and dioles and CD and surfactant through kinetic methods. The formation of complexes CD-sunfactante also has been analyzed by difusiometría NMR. It has linked an analysis of the ability of microenulsiones the time to change the reactivity of Benzoyl chloride and reactions metal-ligando. Also explored is the ability to vesículas as changes in the reactivity.

Author: NESTOR JERÉMIE.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: CSIC.
Place of preparation: UNVIERSITAT DE BARCELONA, FACULTAT DE QUÍMICA.

Author: PEREIRA LACHATAIGNERAIS JOEDMI.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: IIIQAB-CSIC.
Place of preparation: IIIQAB-CSIC.

Summary: The lipid vesicles systems are of great interest because of its similarity to the cell membranes. The object of study of this thesis has been the interaction of liposomes surfactants, and surfactant incorporation of cholesterol in the lipid bilayer, as well as their mechanical properties. They have been trained systems liposomes of phosphatidylcholine (PC) by applying ultrasonic energy to dispersions previously extruídas. Set the time and the power of sonication yielded vesicles with a low degree of polidispersión and lamelaridad. The behavior of viscoelástico concentrated dispersions of liposomes has been compared with systems emulsions, which are widely studied through rheology. 0.83 to phi = 0.50. It proposed a compact structure of the vesicles to explain the resistance to deformation at high volume fractions, it was seen as a de facto obstruction measures conductivity. We studied the multi-formed dioleoil phosphatidylcholine (DOPC), mixtures of DOPC-dodecil sodium sulfate (SDS) and DOPC-SDS-colesterol employee technique diffraction rayos-Xa angle rasante (GISAX). The multislice ordered showed the presence of phase three-dimensional romboédrica (R) at low moisture conditions (RH = 1 and 30%), while the increase in relative humidity (RH = 65%) were detected only the presence of a lamelar phase (L). Thus, in samples DOPC / SDS content surfactant seems to increase the distance between the pores of the R phase, however, the SDS does not affect significantly the distance lamelar repetition. The different content of cholesterol in the bicapas showed an increase in the parameter of the R phase, which makes us believe that the increase in distance between the pores is independent of the molecule contained in the phospholipid bilayer. The calculation of the electron density profiles you in the samples DOPC / Chol can detect a decrease in the water interlamelar between groups regarding polar samples DOPC / SDS. The interaction between liposomes loaded and anionic surfactant SDS was studied by the technique of dynamic laser light scattering (DLS). The interaction of anionic liposomes (phosphatidylcholine / dipalmitoil fosfatidil glycerol) and SDS has shown erratic behavior of the size and intensity dispersed when the SDS concentration is close wing concentration micelar criticism (cmc). However, when the SDS concentration is above the cmc, detected the solubilization of liposomes. This allows us to conclude that when the SDS concentration is below the cmc, different electrostatic charge can control the interaction. The interaction between cationic liposomes (phosphatidylcholine / bromide didodecil dimethyl ammonium) and SDS is a process that happens very quickly. In SDS concentration near the cmc the solubilization is not complete. However, with increasing concentration and SDS will get a final value of scattered intensity very low which suggests the solubilization of lipid molecules. The latter interaction (PC / DDAB - SDS) was studied using the technique Cryo-TEM from cuale were detected different types of structures in the early stages and at the end of the interaction. Discoidales micelles were observed at all stages shown suggesting that these structures are essential and stable in this interaction. In addition, it was observed tubular structures, micelles glublares and small vesicles in the early stages. The vesicles 8 small 203 s, and micelles discoidales micelles glublares showed great stability along the interaction PC / DDAR - SDS.

Author: GODOY LÓPEZ ANA.
Year: 2005.
University: SANTIAGO DE COMPOSTELA [www.usc.es].
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: Spectroscopic Study surfactant / cyclodextrin. Displays behavior where there is interaction between the cyclodextrin and the addition micelar. There cyclodextrin free balance with the system micelar. There is a competition between the surfactant monomers and the substrate by complejarse with cyclodextrin. Study kinetic systems surfactant / cyclodextrin. A kinetic study was conducted with different substrates, cyclodextrins and surfactants. There was a new model of a different complexion to the competitive model of cooperative complexion. Reactivada chemistry in ionic liquids. We studied the transfer of nitrous group from N-metil-N-nitrososulfonamida (MNTS) to secondary amines in various ionic liquids. The behavior found in ionic liquids is expected based on their polarity parameters according to the equation Kamlet-Taft obtained for various molecular solvents.

Author: GUERRERO MARTÍNEZ ANDRÉS.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTAD DE CC. QUÍMICAS, UCM.

Summary: The Ciclodextrinas (CDs) are cyclic oligosaccharides consisting of six, seven or eight waste glucopiranosa united through links glucosidic high (1-4), called alpha, beta and gamma-CD respectively. Because of its macrocyclic structure, ownership more representative of those macrociclos is its ability to form complexes including type huésped-anfitrión with molecules anfifílicas. The phenomenon of complex formation is influenced by various effects, including van der Waals interactions, hydrogen bond, and changes in the states of hydration that occur between the host and guest molecules. In all cases, it has conducted a detailed study of the water systems anfifílico +, CD + water and anfifílico + CD + water. The thermodynamic properties of processes autoasociación of spices anfifílicas, and the formation of inclusion complexes have been obtained from genetic volumes and compresibilidades molars. Additionally, it has used the technique 1H NMR, having given the continued stability and aggregates through complex parameters such as displacement chemical ROE intensities and ratios autodifusión. They have sometimes been compared to those obtained from the technique of dynamic light scattering. In the case of fluorescent species have been conducted experiments absorption UV-vis and provide steady-state fluorescence and resolved in time, from which have been derived parameters such as absortividdes, quantum yields and lifetimes of the states excited, which have been very sensitive to the processes of molecular encapsulation. Within systems species anfifílicas, have studied the complex formed by the beta-CD and a drug of great interest, as is the hydrochloride Propafenona. Additionally, we have investigated the formation of complexes beta, and gamma-CD with an ionic surfactant type gémini, built by a spacer oxietilénico and two hydrocarbon chains derived from bromide dodeciltrimetilamonio. Other surfactants studied, in this case non-ionic, have been family members of Igepales, determining the dependence of the different properties associated with the aggregation and formation of inclusion complexes with the size of his chain oxietilénica.