It is the goal of this body of work to research an assortment of different photoacid generators (PAGs) and quantify their ability to perform the decomposition of poly(propylene carbonate) (PPC). Adding PAGs to PPC allows for a decreased polymer decomposition temperature, which can in turn be used as a sacrificial polymer for the fabrication of various microelectromechanical and microfluidic devices. A focus will be placed on relating the properties of the PAG such as acid strength, acid volatility, and PAG activation to processing issues like percentage of total film decomposition, amount and composition of film residue, decomposition rate, decomposition temperature, and environmental dependencies. This research discovered that the use of superacid triflic and nonaflic based PAGs were not adequate for the decomposition of PPC due to the high vapor pressure of the acid. Furthermore, the non-fluorinated sulfonic acid based PAGs do not posses the super-acid level acidity needed to sufficiently decompose PPC. Conversely, a perfluorinated methide and a tetrakis(pentafluoropheyl)borate based PAG both demonstrated the capability for high level PPC decomposition. Building on the knowledge gained through experimentation with these individual PAGs, the creation of a novel Combination PAG was accomplished. The Combination PAG uses acid groups with different physical properties collectively working to achieve what neither could complete individually.

Light as a “green” source of energy has become increasingly attractive throughout the past century and has shown versatility for the application of activating chemical reactions. Compared with traditional energy sources, it provides a more direct, selective and controllable method. My PhD study was focused on the study of photochemistry of organic materials in two different systems. The first system is regarding reversible photoacids which generate protons on irradiation. With the aim of systematically studying these novel types of long lived photoacids, a series of photoacids was designed, synthesized and whose chemical mechanism was thoroughly investigated. This type of photoacid changes from a weak acid to a strong acid with a pH change of several units, which achieves nearly complete proton dissociation upon visible light irradiation. The whole process is reversible and the half-life of the proton-dissociation state is long enough to be used in many applications. Besides fundamental studies, different applications based on this type of photoacids were also completed. An esterification reaction was catalyzed and the volume of a pH-sensitive polymer was altered due to the large amount of photo generated protons from this photoacid. A reversible electrical conductivity change of polyaniline (PANI) was also achieved by doping with this reversible photoacid. In order to induce a large conductivity increase, an irreversible photoacid generator (PAG) was embedded in a novel PANI/PAG/PVA novel composition. In this system, Poly (vinyl alcohol) (PVA) forms a hydrogen-bonding network to facilitate proton transfer between the PAG and PANI. A final electrical conductivity of 10-1 S cm-1 was successfully achieved after irradiation. The second system in which I explored photochemistry of organic molecules concerns Photoretro-Diels-Alder (PrDA) reactions and a variety of Diels-Alder (DA) adducts were designed for these studies. UV light was used to trigger the retro-Diels-Alder reactions. Quantum yield of iv each DA adducts was investigated. This revealed that the photo-reactivity of this process depends on the electron-donating ability of the diene and the electron-withdrawing ability of the dienophile component. Mechanistic studies of this PrDA reaction reveal that a charge-separated intermediate is generated from a singlet excited state. This was applied to an unsaturated cyclic α-diketones (DKs), which underwent PrDA reactions and generated anthracene derivatives and carbon monoxide (CO), which itself plays profound and important roles in biological systems. These unsaturated cyclic α-diketones (DKs) encapsulated in micelles are effective CO-releasing molecules (CORMs) and are capable of carrying and releasing CO in cellular systems. This novel type of organic CORMs has potentially low toxicity and generates fluorescence, which provides a useful tool for the study of the biological functions of CO.

The photochemistry of several novel photoacids was addressed experimentally and theorectically. Initial studies focused on the excited-state proton transfer (ESPT) of several chiral phtoacids and explored the effects of chirality on ESPT; subsequent studies examined photochemistry and photophysics of "super" photoacid N-methyl-6-hydroxyquinolinium (MHQ). In the initial studies, no enantioselectivity was observed from the chiral photoacids to various chiral proton acceptors. In the later studies examining ESPT in MHQ both experimentally and theoretically, the excited-state acidity constant of the photoacid was determined to be an unprecedented -7, making it the strongest photoacid reported in the literature to-date. Consideration was then given to applications of the novel photoacid including its properties as a photoinitiator in cationic polymerizations and as a photochemical probe in gas-expanded liquids and in the Nafion membrane. In the course of these studies, an interesting fluorescence quenching effect was observed that became the subject of some exploratory studies that suggest a nucleophilic quenching mechanism.

In chapter I Photo-retro-Diels-Alder (PrDA) reactions of a variety of Diels Alder (DA) adducts were studied. Experimental results showed that the photoreactivity (quantum yield) depends on the electron-donating ability of the diene component and the electronwithdrawing ability of the dienophile component. The mechanism was studied by trapping the reaction intermediate, O2 quenching and femtosecond time-resolved absorption spectroscopy. All the results support a mechanism that involves a charge-separated intermediate generated from a singlet excited state. The PrDA reaction may find applications in photoresponsive materials, photolithography, drug delivery and mechanistic research. Chapter II shows two applications of the PrDA reaction. The first, being the formation of the 2 nd -ring DA adduct together with the central-ring adduct in a reaction of pentacene and tetracyanoethylene (TCNE) at room temperature. DFT calculations showed that the difference between the free energy of the two isomers is about 3.9 kcal/mol. Photo- and thermally induced isomerization between the central-ring adduct and the 2nd -ring adduct were studied in solutions and in polymer films. In solution, the less stable 2nd -ring adduct can be completely converted to the more stable central-ring adduct either thermally or photochemically, but the reverse transformation does not occur. In a polymer matrix, isomerization can be photochemically induced in both directions at different wavelengths, which results in a photoswitchable system. Formation of pentacene in the photochemical experiments was also observed, which supports an isomerization process involving a photoretro-Diels Alder (PrDA) reaction. iv The second application was the design and synthesis of a polymer with an anthracene diketone moeity which could undergo a PrDA reaction which should result in significant conductivity changes. Although the synthesis of this type of polymer was unsuccessful during this study, we still believe in the theoretical soundness of the synthesis and utility of this type of polymer. Chapter IV undertakes the study of a class of photoacids which are based on a merocyanine core. These photoacids have been studied and characterized using UV-Vis spectroscopy and the pH of two photoacids have been shown to decrease by 2.0 units upon irradiation with blue light. In addition, the relaxation times of these photoacids have been studied in water and ethanol. We have taken one step further and synthesized and characterized three polymers which have a photoacid moeity in them. These polymers respond to visible light reversibly in solution and in solid state.

Two-photon absorption (2PA) has been used for a number of scientific and technological applications, exploiting the fact that the 2PA probability is directly proportional to the square of the incident light intensity (while one-photon absorption bears a linear relation to the incident light intensity). This intrinsic property of 2PA leads to 3D spatial localization, important in fields such as optical data storage, fluorescence microscopy, and 3D microfabrication. The spatial confinement that 2PA enables has been used to induce photochemical and photophysical events in increasingly smaller volumes and allowed nonlinear, 2PA-based, technologies to reach sub-diffraction limit resolutions. The primary focus of this dissertation is the development of novel, efficient 2PA, fluorene-based molecules to be used either as photoacid generators (PAGs) or fluorophores. A second aim is to develop more effective methods of synthesizing these compounds. As a third and final objective, the new molecules were used to develop a write-once-read many (WORM) optical data storage system, and stimulated emission depletion probes for bioimaging. In Chapter I, the microwave-assisted synthesis of triarylsulfonium salt photoacid generators (PAGs) from their diphenyliodonium counterparts is reported. The microwave-assisted synthesis of these novel sulfonium salts afforded reaction times 90 to 420 times faster than conventional thermal conditions, with photoacid quantum yields of new sulfonium PAGs ranging from 0.01 to 0.4. These PAGs were used to develop a fluorescence readout-based, nonlinear three-dimensional (3D) optical data storage system (Chapter II). In this system, writing was achieved by acid generation upon two-photon absorption (2PA) of a PAG (at 710 or 730 nm). Readout was then performed by interrogating two-photon absorbing dyes, after protonation, at 860 nm. Two-photon recording and readout of voxels was demonstrated in five and eight consecutive, crosstalk-free layers within a polymer matrix, generating a data storage capacity of up to 1.8 x 1013 bits/cm3. The possibility of using these PAGs in microfabrication is described in Chapter III, where two-photon induced cationic ring-opening polymerization (CROP) crosslinking of an SU8 resin is employed to produce free-standing microstructures. Chapter IV describes the investigation of one- and two-photon stimulated emission transitions by the fluorescence quenching of a sulfonyl-containing fluorene compound in solution at room temperate using a picosecond pump-probe technique. The nature of stimulated transitions under various fluorescence excitation and quenching conditions were analyzed theoretically, and good agreement with experimental data was demonstrated. Two-photon stimulated transitions S1 to S0 were shown at 1064 nm. The two-photon stimulated emission cross section of the sulfonyl fluorophore was estimated as aproximately 240 - 280 GM, making this compound a good candidate for use in two-photon stimulated emission depletion (STED) microscopy.

O presente estudo versa sobre a proposição ou extensão de modelos simples para descrever os seguintes fenômenos envolvendo agregados anfifílicos: i-) Influência de sal na concentração micelar crítica (CMC) e número médio de agregação () de micelas zwitteriônicas. ii-) Influência da interação eletrostática (neste caso, repulsiva) e tamanho de \"domínios\" nas isotermas de monocamadas iônicas insolúveis. iii-) Influência do tamanho e polaridade do \"pool\" aquoso de micelas reversas de AOT na reprotonação de sondas fotoácidas aniônicas. Em i-), foi assumido o formalismo termo-molecular para a energia livre de micelização, necessária nas estimativas da CMC e . A energia livre de micelização foi descrita como aditiva, com termos descrevendo a interação interfacial do agregado com o solvente (no caso, água), a repulsão estérica entre as \"cabeças\" do detergente, empacotamento das \"caudas\" e interação dipolar entre os \"zwitterions\". Embora nos formalismos termo-moleculares convencionais, micelas zwitteriônicas não sejam afetadas por eletrólitos, dados experimentais de supressão de fluorescência, salto de pH com sondas fotoácidas, espalhamento de luz dinâmico e estático e condutividade indicam que micelas zwitteriônicas \"ligam\" íons e \"ligam\" seletivamente. A ligação iônica pode ser tratada como um processo de absorção ou adsorção e muda a interação eletrostática das \"cabeças\". Assim, o formalismo termo-molecular foi estendido para incluir as propriedades elétricas de um capacitor com a casca externa permeável aos íons como modelo de micela zwitteriônica. Em ii-), uma nova expansão para potenciais repulsivos (chamada de expansão y) foi aplicada ao problema da interação entre detergentes iônicos em monocamadas insolúveis e comparada com a expansão virial. A interfase foi modelada como uma mistura de pseudo-fluidos bidimensionais, no nível de descrição de McMillan-Mayer (onde o solvente não aparece explicitamente, ou seja, a pressão calculada é uma pressão osmótica). A interação intermolecular na interfase foi considerada como a soma de um potencial de curto alcance (disco rígido) e um termo de longo alcance (potencial de campo médio). Na transição entre as fases líquido-condensada e líquido-expandida, a pressão do sistema é descrita por uma interpolação entre dois subsistemas na mesma densidade superficial. Finalmente em iii-), um modelo para reprotonação de uma sonda fotoácida residindo no pool aquoso de micelas reversas de AOT foi desenvolvido. A sonda (8-hidroxi-1,3,6-pirenotrisulfonato) foi tratada como uma partícula esférica posicionada no centro de um poro esférico (\"pool\" da micela reversa). A constante de reprotonação no poro foi calculada via equação de Debye-Smoluchowski junto com o potencial de força média calculado segundo a equação de Poisson-Boltzmann. O efeito da constante dielétrica aparente na reprotonação foi explorado. / The present work focus on the proposition or extension of simple models to describe the following phenomena involving amphiphile self-association aggregates: i-) Salt influence on the critical micelle concentration (CMC) and on the averaged association number () of zwitterionic micelles. ii-) Influence of the electrostatic interaction (repulsive, in this case) and of the domain size in the isotherms for ionic insoluble monolayers. iii-) Effect of size and polarity of the aqueous pool of AOT reverse micelles in the reprotonation of anionic photoacid probes. For i-), the thermo-molecular formalism for the micellization free energy, necessary for the estimate of the CMC and was assumed. The micellization free energy was described by the addition of the following terms: the interfacial interaction of the aggregate with the solvent (water, in this situation), the steric repulsion among the surfactant headgroups, the packing of the hydrocarbon tails, and the dipolar interaction among the headgroup dipoles. Although in the conventional thermo-molecular formalism zwitterionic micelles are not affected by electrolytes, experimental data including fluorescence quenching, próton jump of photoacid probes, static and dynamic light scattering, and conductivity demonstrate that these aggregates bind ions and bind selectively. The ionic binding can be treated as an absorption or adsorption process and change the electrostatic interaction among the headgroup. Thus, the thermo-molecular formalism was extended to include the electrical properties of a capacitor having the external shell permeable to ions as model of zwitterionic micelles. For ii-), a new expansion for the repulsive potentials (called y expansion) was applied to the problem of the interaction between surfactants in an insoluble monolayer and compared with the virial expression. The interface was modeled as a mixture of two-dimensional pseudo-fluids in McMillan-Mayer description level where the solvent does not appears explicitly, that is the calculated pressure is an osmotic pressure. The interfacial intermolecular interaction was considered as the sum of a short-range potential (hard disc) and a long-range term (mean field potential). In the condensed liquid and expanded liquid transition, the surface pressure can be described by an interpolation between two subsystems at the same surface density. Finally in iii-), a recombination model for a photoacid probe residing in the aqueous core of AOT reverse micelles was developed. The probe (8-hidroxi-1,3,6-pyrenetrisulfonate) treated as a spherical particle was positioned in the center of a spherical pore (micelle aqueous pool). The reprotonation was calculated by the Debye-Smoluchowski equation added to the potential of mean force derived from the Poisson-Boltzmann equation. The effect of the apparent dielectric constant in the reprotonation was explored.

Neste trabalho foram estudadas as propriedades fotoquímicas e fotofisicas do composto bi-cromofórico 1-(2-quinolil)-2-naftol (2QN). Este composto reúne dois sistemas prototrópicos de estado excitado intermoleculares bem conhecidos (2-naftol, fotoácido e quinolina, fotobase) para um sistema intramolecular. Esta escolha deveu-se à conveniência dos pKa\'s e pKa*\'s e tempos de vida de estado excitado do 2-naftol (2N) da quinolina (Q), os quais, em princípio, permitem reações prototrópicas de estado excitado em solução neutra. Desta transformação de sistema inter para intramolecular especula-se obter um \"precursor\" para obtenção de polímeros condutores de prótons. Através dos espectros de absorção e fluorescência, verificou-se que os dois cromóforos do 2QN se comportam independentemente, porém os rendimentos quânticos de fluorescência ( &#934;f) em toda faixa de pH e em vários solventes orgânicos são muito menores que aqueles dos compostos isolados. Esta diminuição de &#934;f é atribuida ao efeito supressivo do cromóforo vicinal. Através dos espectros de fluorescência em solventes orgânicos (Acetonitrila, Hexano e EtOH) sugere-se a ocorrência de transferência de próton intramolecular. Calculou-se via ab initio pelo método restrito Hartree-Fock (RHF) utilizando-se o programa Gaussian a estrutura do 2QN e obteve-se um ângulo diedro de ~42º entre dois cromóforos que impede a rotação livre dos mesmos. Resultado este em boa concordância aos de difração de R-X (~39º). Observou-se a reação fotoquímica induzida por UV do 2QN em solventes alcoólicos (EtOH, MeOH). O fotoproduto foi caracterizado por espectroscopia de RMN (1H, 13C, Dept, COSY e Hetcor), CG-Massa e Infra-vermelho. O fotoproduto principal obtido sugere um mecanismo de reação via SN1Ar intramolecular pelo ataque do átomo de oxigênio do naftolato ao grupo quinolínico. Além do 2QN preparou-se os derivados 2QNCH2+I- e 2QNCH3+I- (compostos inéditos) para auxiliar as atribuições acima. Em matrizes vítreas orgânicas observa-se um drástico aumento em &#934;f e de fosforescência atribuídos ao decréscimo do grau de liberdade rotacional dos rotâmeros do 2QN. Finalmente pelo espectro de luminescência em fase sólida sugere-se a transferência de próton intra- e intermolecular o que ressalta a interesse do 2QN tanto de suas propriedades intrínsecas prototrópicas, quanto como precursor para um sistema supramolecular fotoativado de transferência de prótons. / In this work the photochemical and photophysical properties of the bichromophore 1-(2-Quinolyl)-2-Naphthol (2QN) were studied. This compound associates two well known excited stated intermolecular prototropic systems (2-Naphthol, photoacid and Quinoline, photobase) into an intramolecular system. The convenience of the pKa\' s, pKa*\' s and excited state lifetimes of 2-Naphthol and of Quinoline allows in principle excited state prototropic reactions in neutral solutions. From this transformation of an intermolecular to an intramolecular system it is speculated to obtain a precursor for a proton conductor polymer. The two chromophores of 2QN were found to behave independently by absorption and fluorescence analysis, however, the fluorescence quantum efficiency (&#934;F) at all pH\' s as well in various organic solvents is much smaller than that of isolated compounds. The decrease in <!>F is attributed to the quencher effect of the vicinal chromophore. From the fluorescence spectra in organic solvents (Acetonitrile, Hexane and EtOH), the occurrence of intramolecular proton transfer is suggested. Ab initio calculations by the restricted Hartree-Fock (RHF) using Gaussian program modeled the structure of 2QN with a dihedral angle ~42º between two chromophore planes that hinders the :free rotation. A result in good agreement with that found by X-ray diffraction (~39º). A UV induced photochemical reaction at 2QN in alcoholic solvents (EtOH, MeOH) is observed. The photoproduct was characterized by NMR (1H, 13C, Dept, COSY and Hetcor), GC-mass and IR spectroscopy. The main photoproduct suggests a SN1Ar reaction mechanism by the attack of the naphtholate oxygen on quinolinium. Besides 2QN, two new derivatives 2QNCH2+I-and 2QNCH3+I- (new compounds) were prepared in order to better establish the attributions above. In organic glassy matrixes a drastic increase of &#934;F and of phosphorescence attributed to the decrease in rotational (librational) mobility of 2QN\' s is observed. Finally, from the luminescence spectra in solid phase both intra- and intermolecular proton transfer is suggested, pointing out the interest in the study of 2QN to generate a proton transfer supramolecular photoinduced system.

N-methyl-6-hydroxyquinolinium (NM6HQ) is a powerful excited-state proton donor, exhibiting a huge pKa drop from 7.2 in the ground state to -7 in the excited state. The zwitterionic nature of the proton transfer product encourages intramolecular electron transfer away from the hydroxyl moiety to the distal ring, allowing for a large pKa jump in the excited state. This process is reversible, making the NM6HQ salts powerful transient superacids. We have investigated the excited-state proton transfer (ESPT) from NM6HQ salts to various basic solvents (alcohols, DMSO). A model has been developed that adequately describes the ion-dipole interactions in the ESPT geminate-recombination process. Our studies have shown that the counterion plays a large role in the ESPT. Likewise, initiation of cationic polymerization is controlled by the counterion. NM6HQ perfluoroalkylsulfonates appear to be the first molecules reported which are capable of initiating aliphatic epoxide polymerization at room temperature through a proton transfer mechanism.

Neste trabalho foram estudadas as propriedades fotoquímicas e fotofisicas do composto bi-cromofórico 1-(2-quinolil)-2-naftol (2QN). Este composto reúne dois sistemas prototrópicos de estado excitado intermoleculares bem conhecidos (2-naftol, fotoácido e quinolina, fotobase) para um sistema intramolecular. Esta escolha deveu-se à conveniência dos pKa\'s e pKa*\'s e tempos de vida de estado excitado do 2-naftol (2N) da quinolina (Q), os quais, em princípio, permitem reações prototrópicas de estado excitado em solução neutra. Desta transformação de sistema inter para intramolecular especula-se obter um \"precursor\" para obtenção de polímeros condutores de prótons. Através dos espectros de absorção e fluorescência, verificou-se que os dois cromóforos do 2QN se comportam independentemente, porém os rendimentos quânticos de fluorescência ( &#934;f) em toda faixa de pH e em vários solventes orgânicos são muito menores que aqueles dos compostos isolados. Esta diminuição de &#934;f é atribuida ao efeito supressivo do cromóforo vicinal. Através dos espectros de fluorescência em solventes orgânicos (Acetonitrila, Hexano e EtOH) sugere-se a ocorrência de transferência de próton intramolecular. Calculou-se via ab initio pelo método restrito Hartree-Fock (RHF) utilizando-se o programa Gaussian a estrutura do 2QN e obteve-se um ângulo diedro de ~42º entre dois cromóforos que impede a rotação livre dos mesmos. Resultado este em boa concordância aos de difração de R-X (~39º). Observou-se a reação fotoquímica induzida por UV do 2QN em solventes alcoólicos (EtOH, MeOH). O fotoproduto foi caracterizado por espectroscopia de RMN (1H, 13C, Dept, COSY e Hetcor), CG-Massa e Infra-vermelho. O fotoproduto principal obtido sugere um mecanismo de reação via SN1Ar intramolecular pelo ataque do átomo de oxigênio do naftolato ao grupo quinolínico. Além do 2QN preparou-se os derivados 2QNCH2+I- e 2QNCH3+I- (compostos inéditos) para auxiliar as atribuições acima. Em matrizes vítreas orgânicas observa-se um drástico aumento em &#934;f e de fosforescência atribuídos ao decréscimo do grau de liberdade rotacional dos rotâmeros do 2QN. Finalmente pelo espectro de luminescência em fase sólida sugere-se a transferência de próton intra- e intermolecular o que ressalta a interesse do 2QN tanto de suas propriedades intrínsecas prototrópicas, quanto como precursor para um sistema supramolecular fotoativado de transferência de prótons. / In this work the photochemical and photophysical properties of the bichromophore 1-(2-Quinolyl)-2-Naphthol (2QN) were studied. This compound associates two well known excited stated intermolecular prototropic systems (2-Naphthol, photoacid and Quinoline, photobase) into an intramolecular system. The convenience of the pKa\' s, pKa*\' s and excited state lifetimes of 2-Naphthol and of Quinoline allows in principle excited state prototropic reactions in neutral solutions. From this transformation of an intermolecular to an intramolecular system it is speculated to obtain a precursor for a proton conductor polymer. The two chromophores of 2QN were found to behave independently by absorption and fluorescence analysis, however, the fluorescence quantum efficiency (&#934;F) at all pH\' s as well in various organic solvents is much smaller than that of isolated compounds. The decrease in <!>F is attributed to the quencher effect of the vicinal chromophore. From the fluorescence spectra in organic solvents (Acetonitrile, Hexane and EtOH), the occurrence of intramolecular proton transfer is suggested. Ab initio calculations by the restricted Hartree-Fock (RHF) using Gaussian program modeled the structure of 2QN with a dihedral angle ~42º between two chromophore planes that hinders the :free rotation. A result in good agreement with that found by X-ray diffraction (~39º). A UV induced photochemical reaction at 2QN in alcoholic solvents (EtOH, MeOH) is observed. The photoproduct was characterized by NMR (1H, 13C, Dept, COSY and Hetcor), GC-mass and IR spectroscopy. The main photoproduct suggests a SN1Ar reaction mechanism by the attack of the naphtholate oxygen on quinolinium. Besides 2QN, two new derivatives 2QNCH2+I-and 2QNCH3+I- (new compounds) were prepared in order to better establish the attributions above. In organic glassy matrixes a drastic increase of &#934;F and of phosphorescence attributed to the decrease in rotational (librational) mobility of 2QN\' s is observed. Finally, from the luminescence spectra in solid phase both intra- and intermolecular proton transfer is suggested, pointing out the interest in the study of 2QN to generate a proton transfer supramolecular photoinduced system.

O presente estudo versa sobre a proposição ou extensão de modelos simples para descrever os seguintes fenômenos envolvendo agregados anfifílicos: i-) Influência de sal na concentração micelar crítica (CMC) e número médio de agregação () de micelas zwitteriônicas. ii-) Influência da interação eletrostática (neste caso, repulsiva) e tamanho de \"domínios\" nas isotermas de monocamadas iônicas insolúveis. iii-) Influência do tamanho e polaridade do \"pool\" aquoso de micelas reversas de AOT na reprotonação de sondas fotoácidas aniônicas. Em i-), foi assumido o formalismo termo-molecular para a energia livre de micelização, necessária nas estimativas da CMC e . A energia livre de micelização foi descrita como aditiva, com termos descrevendo a interação interfacial do agregado com o solvente (no caso, água), a repulsão estérica entre as \"cabeças\" do detergente, empacotamento das \"caudas\" e interação dipolar entre os \"zwitterions\". Embora nos formalismos termo-moleculares convencionais, micelas zwitteriônicas não sejam afetadas por eletrólitos, dados experimentais de supressão de fluorescência, salto de pH com sondas fotoácidas, espalhamento de luz dinâmico e estático e condutividade indicam que micelas zwitteriônicas \"ligam\" íons e \"ligam\" seletivamente. A ligação iônica pode ser tratada como um processo de absorção ou adsorção e muda a interação eletrostática das \"cabeças\". Assim, o formalismo termo-molecular foi estendido para incluir as propriedades elétricas de um capacitor com a casca externa permeável aos íons como modelo de micela zwitteriônica. Em ii-), uma nova expansão para potenciais repulsivos (chamada de expansão y) foi aplicada ao problema da interação entre detergentes iônicos em monocamadas insolúveis e comparada com a expansão virial. A interfase foi modelada como uma mistura de pseudo-fluidos bidimensionais, no nível de descrição de McMillan-Mayer (onde o solvente não aparece explicitamente, ou seja, a pressão calculada é uma pressão osmótica). A interação intermolecular na interfase foi considerada como a soma de um potencial de curto alcance (disco rígido) e um termo de longo alcance (potencial de campo médio). Na transição entre as fases líquido-condensada e líquido-expandida, a pressão do sistema é descrita por uma interpolação entre dois subsistemas na mesma densidade superficial. Finalmente em iii-), um modelo para reprotonação de uma sonda fotoácida residindo no pool aquoso de micelas reversas de AOT foi desenvolvido. A sonda (8-hidroxi-1,3,6-pirenotrisulfonato) foi tratada como uma partícula esférica posicionada no centro de um poro esférico (\"pool\" da micela reversa). A constante de reprotonação no poro foi calculada via equação de Debye-Smoluchowski junto com o potencial de força média calculado segundo a equação de Poisson-Boltzmann. O efeito da constante dielétrica aparente na reprotonação foi explorado. / The present work focus on the proposition or extension of simple models to describe the following phenomena involving amphiphile self-association aggregates: i-) Salt influence on the critical micelle concentration (CMC) and on the averaged association number () of zwitterionic micelles. ii-) Influence of the electrostatic interaction (repulsive, in this case) and of the domain size in the isotherms for ionic insoluble monolayers. iii-) Effect of size and polarity of the aqueous pool of AOT reverse micelles in the reprotonation of anionic photoacid probes. For i-), the thermo-molecular formalism for the micellization free energy, necessary for the estimate of the CMC and was assumed. The micellization free energy was described by the addition of the following terms: the interfacial interaction of the aggregate with the solvent (water, in this situation), the steric repulsion among the surfactant headgroups, the packing of the hydrocarbon tails, and the dipolar interaction among the headgroup dipoles. Although in the conventional thermo-molecular formalism zwitterionic micelles are not affected by electrolytes, experimental data including fluorescence quenching, próton jump of photoacid probes, static and dynamic light scattering, and conductivity demonstrate that these aggregates bind ions and bind selectively. The ionic binding can be treated as an absorption or adsorption process and change the electrostatic interaction among the headgroup. Thus, the thermo-molecular formalism was extended to include the electrical properties of a capacitor having the external shell permeable to ions as model of zwitterionic micelles. For ii-), a new expansion for the repulsive potentials (called y expansion) was applied to the problem of the interaction between surfactants in an insoluble monolayer and compared with the virial expression. The interface was modeled as a mixture of two-dimensional pseudo-fluids in McMillan-Mayer description level where the solvent does not appears explicitly, that is the calculated pressure is an osmotic pressure. The interfacial intermolecular interaction was considered as the sum of a short-range potential (hard disc) and a long-range term (mean field potential). In the condensed liquid and expanded liquid transition, the surface pressure can be described by an interpolation between two subsystems at the same surface density. Finally in iii-), a recombination model for a photoacid probe residing in the aqueous core of AOT reverse micelles was developed. The probe (8-hidroxi-1,3,6-pyrenetrisulfonate) treated as a spherical particle was positioned in the center of a spherical pore (micelle aqueous pool). The reprotonation was calculated by the Debye-Smoluchowski equation added to the potential of mean force derived from the Poisson-Boltzmann equation. The effect of the apparent dielectric constant in the reprotonation was explored.