Polymer coatings on periodic nanostructures have facilitated advanced applications in various fields. The performance of these structures is intimately linked to their nanoscale characteristics. Smart polymer coatings responsive to environmental stimuli such as temperature, pH level, and ionic strength have found important uses in these applications. Therefore, to optimize their performance and improve their design, precise characterization techniques are essential for understanding the nanoscale properties of polymer coating, especially in response to stimuli and interactions with the surrounding medium. Due to their layered compositions, applying non-destructive measurement methods by X-ray/neutron scattering is optimal. These approaches offer unique insights into the structure, dynamics, and kinetics of polymeric coatings and interfaces. The caveat is that scattering methods require non-trivial data modeling, particularly in the case of periodic structures, which result in strong correlations between scattered beams. The dynamical theory (DT) model offers an exact model for interpreting off-specular signals from periodically structured surfaces and has been validated on substrates measured by neutron scattering. In this dissertation, we improved the model using a computational optimization approach that simultaneously fits specular and off-specular scattering signals and efficiently retrieves the three-dimensional sample profile with high precision. In addition, we extended this to the case of X-ray scattering. We applied this approach to characterize polymer brushes for nanofluidic applications and protein binding to modulated lipid membranes. This approach opens new possibilities in developing soft matter nanostructured substrates with desired properties for various applications. / Doctor of Philosophy / Polymer coatings on nanopatterned surfaces have recently facilitated advanced applications in various fields, particularly biotechnology. For example, multichannel surfaces coated with polymer can serve as nanofluidic devices for precise control of fluid flow in drug screening and detection of specific biomolecules. Moreover, polymer-coated nanopatterned surfaces, which possess similar properties to the extracellular matrix, provide excellent substrates for biological studies. The performance of these systems is closely tied to their nanoscale features, such as the thickness and conformation of the polymer layers. Therefore, high-resolution non-invasive nanoscale characterization techniques are essential for investigating these coatings to optimize their performance and enhance their design. X-ray/neutron scattering offers a non-destructive measurement method with unique capabilities in the nanoscale characterization of polymer coatings. However, scattering methods require non-trivial data modeling, particularly in the case of layered coatings on patterned surfaces. To tackle this challenge, we improved a dynamical theory (DT) model that allows for precise modeling of neutron and X-ray scattering signals from such systems. Using a computational optimization approach, the model enables efficient retrieval of the three-dimensional sample profile with high accuracy. We applied this approach to characterize polymer brushes for nanofluidic applications and protein binding to modulated lipid membranes. This methodology opens up new avenues for developing customizable, nanostructured substrates made from soft materials that possess tailored properties for a wide range of uses.

Apesar de ser utilizado há muito tempo como solvente para espécies orgânicas e inorgânicas, bem como carreador de fármacos, muitos aspectos relativos à auto-associação intermolecular do dimetil sulfóxido (DMSO) e às suas interações com espécies iônicas são ainda motivos de controvérsia na literatura. No presente estudo, a estrutura e ambiente local de dimetil sulfóxido (DMSO) em diferentes meios iônicos foram estudados por meio de três abordagens diferentes. Na primeira abordagem, o efeito de não-coincidência Raman (NCR) observado na banda atribuída ao modo ν(S=O) do DMSO, ca. 1050 cm-1, foi investigado para o líquido puro e em soluções de tetracloreto de carbono (CCl4) e água. Além disso, foi investigado o efeito de espécies iônicas (Kl, KSCN, KBr, TBAN3, TBAOCN, LiClO4, Mg(ClO4)2) na frequência ν(S=O), bem como no NCR das soluções. Os resultados de NCR juntamente com as técnicas de infravermelho, RMN e de medidas de propriedades físico-químicas mostraram que essas espécies iônicas não somente afetam a estrutura de associação do DMSO, como são capazes de interagir fortemente com o solvente. Na segunda abordagem, com a finalidade de modular as propriedades de um líquido iônico, fez-se a análise estrutural das misturas envolvendo DMSO e água como solventes e o líquido iônico EAN como soluto por meio das técnicas de espalhamento de raios-X e de nêutrons. Os resultados mostraram que a estrutura cátion-ânion do EAN é afetada pela presença de DMSO e, que em ambos os solventes são evidentes fortes ligações de hidrogênio entre o cátion EA+ e os oxigênios do solvente e do ânion nitrato. As moléculas de água não afetam drasticamente a estrutura do EAN, pois seu caráter doador/aceptor de LH e seu tamanho permite a formação de pontes entre cátion e o ânion, no entanto, EAN consegue distorcer a rede tridimensional de ligação de hidrogênio da água. Por outro lado, as moléculas de DMSO afastam os ânions da região polar do EA+ na competição pela formação de LH com o cátion e o EAN, por sua vez, provoca a ruptura das estruturas de associação do DMSO. Na terceira abordagem, misturas envolvendo três diferentes SEPs (uma classe de líquidos iônicos); Relina, MUCHCl e DMUCHCl; com DMSO foram investigadas por meio de suas propriedades físico-químicas e por espectroscopia Raman, tendo em vista modular as propriedades dos SEPs. Neste caso, os resultados não apontaram para interações fortes e específicas envolvendo as espécies iônicas e o DMSO, mas a um maior empacotamento do sistema, onde os desvios de suas propriedades físico-químicas com relação à idealidade são negativos e sua mobilidade iônica juntamente com a análise dos espectros vibracionais não evidenciaram interações específicas. No entanto, as viscosidades e densidades diminuíram nas misturas e a mobilidade iônica foi favorecida. / Although it has long been used as a solvent for organic and inorganic species, as well as drug carriers, many aspects concerning the intermolecular self-association of dimethyl sulfoxide (DMSO) and their interactions with ionic species are still controversial in the literature. In the present study, the structure and local environment of dimethyl sulfoxide (DMSO) in different ionic media were studied using three different approaches. In the first approach, the Raman non-coincidence effect (NCE) observed in the band assigned to the DMSO ν(S = O) mode, ca. 1050 cm-1, was investigated for the pure liquid and in its solutions of carbon tetrachloride (CCl4) and water. In addition, the effect of ionic species (K1, KSCN, KBr, TBAN3, TBAOCN, LiClO4, Mg (ClO4)2) on the frequency ν(S = O) as well as the NCE of the solutions were investigated. The results of NCR together with the infrared, NMR and physico-chemical properties measurements showed that these ionic species not only affect the association structure of DMSO, but are also capable of interacting strongly with the solvent. In the second approach, with the purpose of modulating the properties of an ionic liquid, the structural analysis of the mixtures involving DMSO and water as solvents and the ionic liquid EAN as a solute were carried out by X-ray and neutron scattering techniques. The results showed that the cation-anion structure of the EAN is affected by the presence of DMSO and that in both solvents strong hydrogen bonds between the EA+ cation and the oxygen from solvent and from nitrate anion are evident. The water molecules do not affect the structure of the EAN drastically, because its LH donor/acceptor character and its size allows the formation of bridges between cation and anion, however, EAN can distort the hydrogen bonding three-dimensional network in water. On the other hand, the DMSO molecules repels the anions from the polar head of EA+ in the competition in forming LH with the cation, however EAN break down DMSO association structures. In the third approach, mixtures involving three different SEPs (a class of ionic liquids); Relina, MUCHCl and DMUCHCl; with DMSO were investigated by means of their physicochemical properties and by Raman spectroscopy, in order to modulate the properties of SEPs. In this case, the results did not point to strong and specific interactions involving the ionic species and DMSO, but to a greater packaging of the system, where the deviations of its physicochemical properties with respect to the ideality are negative and its ionic mobility together with the analysis of the vibrational spectra showed no specific interactions. However, the viscosities and densities decreased in the mixtures and the ionic mobility was favored.

Apesar de ser utilizado há muito tempo como solvente para espécies orgânicas e inorgânicas, bem como carreador de fármacos, muitos aspectos relativos à auto-associação intermolecular do dimetil sulfóxido (DMSO) e às suas interações com espécies iônicas são ainda motivos de controvérsia na literatura. No presente estudo, a estrutura e ambiente local de dimetil sulfóxido (DMSO) em diferentes meios iônicos foram estudados por meio de três abordagens diferentes. Na primeira abordagem, o efeito de não-coincidência Raman (NCR) observado na banda atribuída ao modo ν(S=O) do DMSO, ca. 1050 cm-1, foi investigado para o líquido puro e em soluções de tetracloreto de carbono (CCl4) e água. Além disso, foi investigado o efeito de espécies iônicas (Kl, KSCN, KBr, TBAN3, TBAOCN, LiClO4, Mg(ClO4)2) na frequência ν(S=O), bem como no NCR das soluções. Os resultados de NCR juntamente com as técnicas de infravermelho, RMN e de medidas de propriedades físico-químicas mostraram que essas espécies iônicas não somente afetam a estrutura de associação do DMSO, como são capazes de interagir fortemente com o solvente. Na segunda abordagem, com a finalidade de modular as propriedades de um líquido iônico, fez-se a análise estrutural das misturas envolvendo DMSO e água como solventes e o líquido iônico EAN como soluto por meio das técnicas de espalhamento de raios-X e de nêutrons. Os resultados mostraram que a estrutura cátion-ânion do EAN é afetada pela presença de DMSO e, que em ambos os solventes são evidentes fortes ligações de hidrogênio entre o cátion EA+ e os oxigênios do solvente e do ânion nitrato. As moléculas de água não afetam drasticamente a estrutura do EAN, pois seu caráter doador/aceptor de LH e seu tamanho permite a formação de pontes entre cátion e o ânion, no entanto, EAN consegue distorcer a rede tridimensional de ligação de hidrogênio da água. Por outro lado, as moléculas de DMSO afastam os ânions da região polar do EA+ na competição pela formação de LH com o cátion e o EAN, por sua vez, provoca a ruptura das estruturas de associação do DMSO. Na terceira abordagem, misturas envolvendo três diferentes SEPs (uma classe de líquidos iônicos); Relina, MUCHCl e DMUCHCl; com DMSO foram investigadas por meio de suas propriedades físico-químicas e por espectroscopia Raman, tendo em vista modular as propriedades dos SEPs. Neste caso, os resultados não apontaram para interações fortes e específicas envolvendo as espécies iônicas e o DMSO, mas a um maior empacotamento do sistema, onde os desvios de suas propriedades físico-químicas com relação à idealidade são negativos e sua mobilidade iônica juntamente com a análise dos espectros vibracionais não evidenciaram interações específicas. No entanto, as viscosidades e densidades diminuíram nas misturas e a mobilidade iônica foi favorecida. / Although it has long been used as a solvent for organic and inorganic species, as well as drug carriers, many aspects concerning the intermolecular self-association of dimethyl sulfoxide (DMSO) and their interactions with ionic species are still controversial in the literature. In the present study, the structure and local environment of dimethyl sulfoxide (DMSO) in different ionic media were studied using three different approaches. In the first approach, the Raman non-coincidence effect (NCE) observed in the band assigned to the DMSO ν(S = O) mode, ca. 1050 cm-1, was investigated for the pure liquid and in its solutions of carbon tetrachloride (CCl4) and water. In addition, the effect of ionic species (K1, KSCN, KBr, TBAN3, TBAOCN, LiClO4, Mg (ClO4)2) on the frequency ν(S = O) as well as the NCE of the solutions were investigated. The results of NCR together with the infrared, NMR and physico-chemical properties measurements showed that these ionic species not only affect the association structure of DMSO, but are also capable of interacting strongly with the solvent. In the second approach, with the purpose of modulating the properties of an ionic liquid, the structural analysis of the mixtures involving DMSO and water as solvents and the ionic liquid EAN as a solute were carried out by X-ray and neutron scattering techniques. The results showed that the cation-anion structure of the EAN is affected by the presence of DMSO and that in both solvents strong hydrogen bonds between the EA+ cation and the oxygen from solvent and from nitrate anion are evident. The water molecules do not affect the structure of the EAN drastically, because its LH donor/acceptor character and its size allows the formation of bridges between cation and anion, however, EAN can distort the hydrogen bonding three-dimensional network in water. On the other hand, the DMSO molecules repels the anions from the polar head of EA+ in the competition in forming LH with the cation, however EAN break down DMSO association structures. In the third approach, mixtures involving three different SEPs (a class of ionic liquids); Relina, MUCHCl and DMUCHCl; with DMSO were investigated by means of their physicochemical properties and by Raman spectroscopy, in order to modulate the properties of SEPs. In this case, the results did not point to strong and specific interactions involving the ionic species and DMSO, but to a greater packaging of the system, where the deviations of its physicochemical properties with respect to the ideality are negative and its ionic mobility together with the analysis of the vibrational spectra showed no specific interactions. However, the viscosities and densities decreased in the mixtures and the ionic mobility was favored.

Title: Self-assembly of polymers with amphiphilic compounds (surfactants) in aqueous solutions Abstract: This PhD Thesis is devoted to the co-assembly in systems containing electrically charged polymers (polyelectrolytes and block copolymers containing polyelectrolyte sequences). I studied the interactions between block copolymers and oppositely charged surfactants in aqueous solutions, and the structure and properties of co-assembled nanoparticles by a combination of several experimental methods. I found that the spontaneous formation, solubility and stability of complex nanoparticles depend not only on the electrostatic attractive forces but also on the hydrophobic effects. In a major part of my Thesis, I studied the interaction of polyelectrolytes with oppositely charged gemini surfactants (containing two charged head-groups interconnected by a short linker and two hydrophobic tails) which is a relatively new topic - much less studied than the co-assembly with conventional single tail surfactants. Better understanding of the formation and properties of complexes containing gemini surfactants and polymers provides knowledge that should lead to novel tailor-made nanoparticles with desired properties for applications in medicine and new technologies (including nano-technologies). We have shown that the...