|Research at Complex Fluids & Interfaces Group|
We are interested in several physical systems and interfaces, which at first sight they do not seem quite related. However, using the new way of thinking developed in the field of Soft Condensed Matter Physics, they are very similar. Examples of the systems are:
We are interested in understanding the structure in these systems, the macroscopic consequence of that structure, and how molecules interact among them to self-organize most of the times along interfaces. Naturally, interaction between interfaces is also of our interest.
In our case interfaces can be of several types. Simple or complex interfaces. Interaction between simple macroscopic surfaces are interesting, particularly to understand wetting and adhesion between them. Complex interfaces can be macroscopic structured interfaces; they are of macroscopic dimensions. However, here molecules are organized in very well defined and fascinating forms. Examples in this case are the Langmuir monolayers at the interface of water and air, and films on solid substrates named Langmuir-Blodgett films. In our group, we study monolayers of fatty acids, fatty amines, proteins with amphiphilic α-helixes, and phospholipids etc.
Other types of complex interfaces are those that we call microscopic interfaces, because they have microscopic dimensions. These interfaces appear typically in ternary systems, which are formed by a surfactant, some kind of oil, and water. In these kinds of systems, the addition of surfactant apparently makes the macroscopic illusion that water and oil are soluble. However, the system self-organizes (microscopically) in such a way creating microscopic surfaces made of surfactant molecules, separating the water and the oil. These surfaces have different shapes forming very peculiar supramolecular structures named spherical micelles, tubular micelles (worm like-micelles), lamellae, bicontinuous structures, etc. Here, we are interested in fluids embedded with these supramolecular structures, and how the fluid behavior is modified by these structures.
Our group is also interested in colloidal particles usually at the air and water interface, or embedded in complex fluids. Here, the colloidal particles moving in random motion are able to probe the properties of complex fluids. These properties can be assessed by tracking the movement of these particles by dynamic light scattering.