Organic ferroelectrics polymers have recently received much interest for use in nonvolatile memory devices. The ferroelectric copolymer poly(vinylidene fluoride- trifluoroethylene) , P(VDF-TrFE), is a promising candidate due to its relatively high remnant polarization, low coercive field, fast switching times, easy processability, and low Curie transition. However, no detailed study of charge injection and current transport properties in P(VDF-TrFE) have been reported in the literature yet. Charge injection and transport are believed to affect various properties of ferroelectric films such as remnant polarization values and polarization fatigue behavior.. Thus, this thesis aims to study charge injection in P(VDF-TrFE) and its transport properties as a function of electrode material. Injection was studied for Al, Ag, Au and Pt electrodes. Higher work function metals such as Pt have shown less leakage current compared to lower work function metals such as Al for more than an order of magnitude. That implied n-type conduction behavior for P(VDF-TrFE), as well as electrons being the dominant injected carrier type. Charge transport was also studied as a function of temperature, and two major transport regimes were identified: 1) Thermionic emission over a Schottky barrier for low fields (E < 25 MV/m). 2) Space-Charge-Limited regime at higher fields (25 < E <120 MV/m). We have also studied the optical imprint phenomenon, the polarization fatigue resulting from a combination of broad band optical illumination and DC bias near the switching field. A setup was designed for the experiment, and validated by reproducing the reported effect in polycrystalline Pb(Zr,Ti)O3 , PZT, film. On the other hand, P(VDF-TrFE) film showed no polarization fatigue as a result of optical imprint test, which could be attributed to the large band gap of the material, and the low intensity of the UV portion of the arc lamp white light used for the experiment. Results suggest using high work function metals for a memory application, as lower leakage would enhance fatigue endurance for P(VDF-TrFE) film.

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<p dir="ltr">Origami has emerged as a design paradigm to realize morphing structures with rich kinematic and mechanical properties. Biological examples augment the potential folding design space by suggesting intriguing routes for achieving and expanding crease patterns which traditional origami laws are unable to capture. Specifically, spring origami theory exploits the material system architecture and energy storage mechanism of the earwig wing featuring one of the highest folding ratios in the animal kingdom (1:18), minimal energy required for deployment and collapse of the wing, and bistability locking the wing in closed, and open configurations for crawling through tunnels, and flight, respectively. The central mechanism responsible for bistability in the wing features a non-developable crease pattern with a non-zero Gaussian curvature. Reconfiguring, or even flattening a structure with such an intrinsic property requires stretching or tearing; soft, rubbery material found in the creases of the central mechanism allows for stretching enabling shape transformations between open and closed states without tearing. In the first part of this thesis, such characteristics are transferred to a synthetic bistable soft robotic gripper leveraging the shape adaptability and conformability exhibited by the biological organism to minimize actuation energy. This is achieved by integrating soft, flexible material in the bioinspired gripper that allows kinematically driven geometries to grasp and manipulate objects without continuous actuation. Secondly, the stiffening effect from spring origami is utilized in a bioinspired wing for an aerial--aquatic robot. Transitions between air and sea in multimodal robots is challenging, however, a structurally efficient and multifunctional membrane is developed to increase locomotive capabilities and longer flights. This is motivated by the flying fish's locomotive modules and origami design principles for deployment and folding. Additionally, to keep the wing in a stiff state while gliding, spring origami bistable units are integrated into the membrane inducing self-stiffening and a global curvature reducing energy expenditure while generating lift. While the previous examples present solutions to adaptive manipulation and membrane multifunctionality, once programmed, their shapes are fixed. In the third application, a class of multistable self-folding origami architectures that are reprogrammable post fabrication are presented. This is achieved by encoding prestrain in bilayer creases with anisotropic shrinkage that change shape and induce a local curvature in the creases in response to external stimuli. The topology of the energy landscapes can thus be tuned as a function of the stimulation time and adaptable post fabrication. The proposed method and model allows for converting flat sheets with arranged facets and prestrained mountain-valley creases into self-folding multistable structures. Lasty, encoding crease prestrain is leveraged to manufacture a biomimetic earwig wing featuring the complex crease pattern, structural stability, and rapid closure of the biological counterpart. The presented method provides a route for encoding prestrain in self-folding origami, the multistability of which is adaptable after fabrication.</p>