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Upcoming advancements in flexible technology require mechanically compliant dielectric materials. Current dielectrics have either high dielectric constant, K (e.g., metal oxides) or good flexibility (e.g., polymers). Here, we achieve a golden mean of these properties and obtain a lightweight, viscoelastic, high-K dielectric material by combining two nonpolar, brittle constituents, namely, sulfur (S) and selenium (Se). This S-Se alloy retains polymer-like mechanical flexibility along with a dielectric strength (40 kV/mm) and a high dielectric constant (K = 74 at 1 MHz) similar to those of established metal oxides. Our theoretical model suggests that the principal reason is the strong dipole moment generated due to the unique structural orientation between S and Se atoms. The S-Se alloys can bridge the chasm between mechanically soft and high-K dielectric materials toward several flexible device applications.

Upcoming advancements in flexible technology require mechanically compliant dielectric materials. Current dielectrics have either high dielectric constant, K (e.g., metal oxides) or good flexibility (e.g., polymers). Here, we achieve a golden mean of these properties and obtain a lightweight, viscoelastic, high-K dielectric material by combining two nonpolar, brittle constituents, namely, sulfur (S) and selenium (Se). This S-Se alloy retains polymer-like mechanical flexibility along with a dielectric strength (40 kV/mm) and a high dielectric constant (K = 74 at 1 MHz) similar to those of established metal oxides. Our theoretical model suggests that the principal reason is the strong dipole moment generated due to the unique structural orientation between S and Se atoms. The S-Se alloys can bridge the chasm between mechanically soft and high-K dielectric materials toward several flexible device applications.

With growing interest and development of large pulsed plasma electric propulsion devices, it has become necessary to accurately measure their thruster performance. Direct thrust measurements are the best way to measure the impulse of a propulsion device which requires it to be mounted entirely on the thrust stand. In many cases this means the thrust stand must support 10 to 100's of kilograms and still be able to resolve mNs worth of impulse. With the development of this new class of thrust stand, an accurate and repeatable method of calibration is needed. Two such calibration methods have been examined and compared. Electrostatic fin (ESF) and piezoelectric impact hammer (PIH) calibration systems were simultaneously tested on a large scale torsional thrust stand system. The use of these two methods allowed the stand to be calibrated over four orders of magnitude, from 0.01mNs to 750mNs. The ESF system produced linear results within 0.52% from 0.01mNs to 12mNs, while the PIH system extended this calibration range from 1mNs to 750mNs with an error of 0.99%. These two calibration methods also agreed within 4.51% over their overlapping range of 10 to 20 mNs., Prepared in collaboration with Univ. of Southern California. For publication in American Institute of Physics: Review of Scientific Instruments: Apr 2011