5o Encontro sobre Estruturas Auto-organizadas em Solucoes e InterfacesMODULATION OF THE INTERFACIAL PROPERTIES OF ZWITTERIONIC AGGREGATES BY IONIC LIQUID: EXPLORING THE CHAMALEON EFFECTPaulo Fernando A. Costaa (PG), Yasmin S. Gomesa (IC), Adriana P. Gerolaa (PQ), Vanessa Nascimentoa (PQ), Franciane D. Souzaa (PQ), Rodrigo Montecinosb (PQ), Haidi D. Fiedlera (PQ), Faruk Nomea* (PQ)a INCT Catalise, Departament of Chemistry, UFSC, Florianopolis, SC, Brazil, b Pontifice Catolic University, Santiago, Chile *e-mail: faruk.nome@ufsc.brINTRODUCTIONDespite the remarkable biological importance, zwitterionic aggregates have been less studied than the others. Such aggregates have the unique feature of change differentially its properties through the incorporation of anions and cations in its interface, this phenomenon is known as "chameleon effect". (1) In this sense, we seek to use the ionic liquids to modulate the properties of zwitterionic aggregates exploring rationally the "chameleon effect". We intend to develop interfaces with different properties for use in catalysis or as biological membranes models.Scheme 1. Rational design of interfaces and modulation of interfacial properties.METHODOLOGYSynthesisThe ionic liquid BMIMBr was synthesized and characterized by 1H NMR and ESI-MS.Formation of zwitterionic aggregatesBMIMBr was used with the zwitterionic surfactant ImS3-14 to form nanostructured aggregates.CharacterizationResonant light scattering: Solubility studies / Formation of nanoaggreagatesSurface tension: Determination of CMCHydrodynamic diameter: SizeZeta potentialFluorescent probe: Pyrene as a polarity probe Kinetic probe: A decarboxylation reaction of 6-nitro-benzisoxazole-3-carboxylate (6-NBIC) as kinetic probe of polarity.RESULTS AND DISCUSSIONSFigure 1. Light scattering of ImS3-14 aggregates on different concentrations of BMIMBr. [ImS3-14]=0.01 mol L-1, pH=7.00 (Bis-Tris) e T=25.0oC.Figure 2. CMC determination by surface tension. [ImS3-14]=0.01 mol L-1, pH=7.00 (Bis-Tris) e T=25.0oC.Figure 3. Zeta potential of ImS3-14 aggregates on different concentrations of BMIMBr. [ImS3-14]=0.01 mol L-1, pH=7.00 (Bis-Tris) e T=25.0oC.Figure 4. (A) Fraction of the species of 6-NBIC on different pH. (B) Progress of the decarboxylation reaction of 6-NBIC monitored by UV-Vis. [Surfact]=0.01 mol L-1 pH=7.00 (Bis-Tris) e T=25.0oC.Figure 5. Decarboxylation reaction mechanism of 6-nitro-benzisoxazole-3-carboxylate.Figure 6. Overlap of rate constants of decarboxylation reactions of 6-NBIC with (A) zeta potential and (B) polarity (Py Scale) in funtion of [BMIMBr]. [6-NBIC] = 5x10-5 mol L-1 [ImS3-14] = 0.01 mol l-1 pH = 7.00 and T = 25.0oC.CONCLUSIONSThe results evidenced a differential and sequential binding of Br and BMIM+, depending on the concentration of ionic liquid in the zwitterionic aggregate studied. The observed effect shows that it is possible to modulate the interfacial properties of the aggregates and finely controlling a set of properties such as zeta potential, polarity, and interfacial composition. Thus, the experimental data allow the rational design of interfaces specifically modulated properties, which enables many different applications, such as catalysis and models of biomembranes. REFERENCES(1) Drinkel, E.; Souza, F. D.; Fiedler, H. D.; Nome, F. Cur. Op. in Colloid and Interface Science, 2013, 44, 2634ACKNOWLEDGEMENTS5o Encontro sobre Estruturas Auto-organizadas em Solucoes e InterfacesRESUMOMODULACAO DAS PROPRIEDADES INTERFACIAIS DE AGREGADOS DIPOLARES IONICOS POR LIQUIDO IONICO: EXPLORANDO O EFEITO CAMALEAOPaulo Fernando A. Costaa (PG), Yasmin S. Gomesa (IC), Adriana P. Gerolaa (PQ), Vanessa Nascimentoa (PQ), Franciane D. Souzaa (PQ), Rodrigo Montecinosb (PQ), Haidi D. Fiedlera (PQ), Faruk Nomea* (PQ)a INCT Catalise, Departament of Chemistry, UFSC, Florianopolis, SC, Brazil, b Pontificia Universidade Catolica, Santiago, Chile