Porous thin films deposited by glancing angle deposition (GLAD) are under study by many groups around the world due to their favorable characteristics, which include high porosity, structural tunability, and unique optical and mechanical properties. In this thesis, template-based fabrication processes are developed in which films deposited at glancing angle act as the master, enabling a variety of materials to be shaped on the micro- and nanoscale. The properties of these micro- and nanostructured films are investigated, particularly with an interest in using these materials in micro-actuator devices.
A single-templating process is used to fabricate metal and polymer thin films with engineered helical pores. Finite element modeling is used to show that the moduli of these materials can be tuned by varying the rise angle of the helices. A double-templating process is presented which can be used to fabricate polymer helices.
The thermal, mechanical, and optical properties of liquid crystalline polymers (LCP) are investigated. It is found that materials which contract in one direction by 22% when heated to 200 °C can be made by photo-polymerization of appropriate monomer mixtures. The thermomechanical properties of these materials are found to depend strongly on the alignment of the liquid crystalline moieties within the film and the applied boundary constraints. These results are confirmed by finite element modeling.
With an interest in shaping liquid crystalline polymers in single and double-templating processes, a nuclear magnetic resonance (NMR) study is conducted to determine the alignment of liquid crystals in a helical GLAD template. It is found that the liquid crystals follow the rise angle of the helices.
Single-templating, double-templating, photopatteming, and micro-transfer printing techniques are used to shape liquid crystalline polymers on the micro and nanoscale. Actuation of the structures formed using each of these techniques is presented. It is found that single-phase photopatteming can be used to pattern planar structures which expand by up to 9% when heated to 200 °C. A single-templating process can be used to make selectively-reinforced liquid crystalline polymer and isotropic polymer layers, which undergo significant changes in surface topography when heated.