News & Seminars | HKUST Department of Physics

Smart materials have attracted great attentions since their properties are able to respond to external stimuli. In this thesis, magnetorheological fluid (MRF), a smart material whose rheology can be controlled by an external magnetic field, has been studied. To improve the functions of MRF, NiNWs are applied to it replacing conventional spherical particles as the dispersed phase. Firstly, a novel and facile method to synthesis NiNWs with large aspect ratio and high purity is developed. Then this method has been modified to have a large scale production, and NiNWs with large aspect ratios are used to fabricate MRFs. These MRF samples provide significantly enhanced shear stress and viscosity under magnetic field, and they also have great stability in suspension. Besides MRF, other smart materials based on nanocomposite are studied as well. For instance, smart window and film is achieved by simply introducing agar into a copolymer aqueous solution. Moreover, there are two kinds of potential smart materials based on AgNWs reported in this thesis. The Janus Ag-Au NWs can be made for thermal sensors, while the AgNW-integrated super elastic hydrogel can be applied into strain sensors. By adjusting the size and shape of the hybrid hydrophilic and hydrophobic patches on a glass matrix fabricated by photolithography, the shape of liquid droplet on its surface can be controlled. This matrix might be useful for the synthesis of 2D nanomaterials. It is believed that smart materials based on nanocomposite have impressive functions and it is worthy to have further researches in this field.