Abstracts

Although the familiarity and simplicity, the water show a set of thermodynamic, dynamics and structural properties which are still subject to intense research. The increase of density as the temperature, of diffusion as the density, or even of ordering with the temperature are examples of some of its unusual behavior. In order to better understand these properties numerous approaches have been used, such as the use of confinement geometries, simplified models, or ever mixtures. Among the confinement geometries used, are those, nanopores, parallel plates and porous media. The porous media are formed by fixed obstacles that impose the additional excluded volume effects to the system. In the case of mixtures, when they occur between liquids able to form hydrogen-bonds, the unusual behavior of water give rise to a set even higher anomalous properties. The water-methanol mixture, for example, has a set of excess properties unable to be described by usual theories. Some examples are the maximum in the specific heat and minimum in excess volume and enthalpy. In this Ph.D. project, we study by numerical simulations, the confinement of water by porous media(or under quenched disorder) and the mixture of water with interacting solutes. The first study is performed using a 2D lattice model which is widely known in the literature. In a second stage, we study the influence of interacting solutes on the properties of lattice and continuous models. For the lattice model, we develop a solute model and a technique to simulate mixtures of lattice models at constant pressure. Using this technique, we study the excess properties of the mixture. For the continuous model we study the influence of a dimeric solute on the TMD of a water-like model and posteriorly we study the excess properties of this type of mixture. Apesar de sua familiaridade e simplicidade, a gua apresenta um conjunto propriedades termodinmicas, dinmicas e estruturais que so ainda objeto de intensa pesquisa. O aumento da densidade com a temperatura, da difuso com a densidade, ou ainda do ordenamento com a temperatura so exemplos de alguns de seus comportamentos no usuais. Com a finalidade de melhor compreender tais propriedades inmeras abordagens tm sido utilizadas, tais como o uso geometrias de confinamento, modelos simplificados ou at mesmo misturas. Dentre as geometrias confinantes frequentemente usadas, encontra-se, nanoporos, placas paralelas e meio porosos. Os meios porosos so formados por obstculos fixos que impem efeitos de volume excludo adicionais ao sistema. J no caso de misturas quando elas ocorrem entre lquidos capazes de formar ligaes de hidrognio, o comportamento no usual da gua d origem a um conjunto ainda maior de propriedades anmalas. A mistura gua-metanol por exemplo, munida de um conjunto propriedades de excesso incapazes de serem descritas pelas teorias usuais. So alguns exemplos, o mximo no calor especfico e o mnimo no volume e entalpia de excesso. Neste projeto de doutoramento, ns estudamos por simulaesAdvisors/Committee Members: Barbosa, Marcia Cristina Bernardes.