Preparation and properties of materials for intelligent systems

Anotace

Stimulus-responsive materials, often referred as intelligent systems, are of high interest for their unique controllable properties. As an external stimulus mainly pH, UV light, electric or magnetic fields are involved. A branch of intelligent systems which change their physical properties upon an application of external electric or magnetic fields are called smart fluids. Firstly, the electrorheological fluids were discovered by Winslow [1], who observed the formation of fibrous structures formed from electrically polarizable particles within the liquid medium in 1948. In the same year, Rabinow has observed the same phenomenon with magnetic particles in the liquid medium, and invented the magnetic fluid clutch [2]. Since their discovery the smart fluids have been a matter of an intensive research in many research groups. In the case of electrorheological fluids, their rheological parameters can easily be controlled through an application of an external electric field. Such ability comes from a creation of internal chain-like structures within them due to dipole-dipole interactions of the dispersed particles leading to a change from nearly Newtonian to Bingham-like behaviour.