Silicone, dielectric permittivity

A simple nondestructive capacitance method is proposed (Adamyan et al, 2006) for the determination of basic PSi parameters such as layer thickness, porosity and dielectric permittivity. The method is based on two comparative measurements of the capacitance of the metal/PSi/single crystalline silicon/metal structure one measurement is taken when there are air-filled pores, while the other measurement involves pores filled by an organic compound with a high value of dielectric permittivity. Comparison of results obtained in Adamyan et al. (2006) by the ball lap and the gravimetric techniques before and after anodization, with the data of capacitance measurements carried out with the same samples prior to their destruction, shows sufficiently good agreement. 

Kussmaul, B., Risse, S., Kofod, G.,Wach, R., Wegener, M., McCarthy, D.N., Kr Ger, H., Gerhard, R., 2011. Enhancement of dielectric permittivity and electromechanical response in silicone elastomers molecular grafting of organic dipoles to the macromolecular network. Adv. Funct. Mater. 21,4589-4594. 

Kruger, H. Gerhard, R., Enhancement of Dielectric Permittivity and Electromechanical Response in Silicone Elastomers Molecular Grafting of Organic Dipoles to the Macromolecular Network. Adv. Funct. Mater. 2011, 21, 4589-4594. Zhang, B. Zhuo, D. Gu, A. Liang, G. Hu, J.-T. Yuan, L., Preparation and Properties of Addition Curable Silicone Resins with Excellent Dielectric Properties and Thermal Resistance. Polym. Eng. Sci. 2011, 52, 259-267. 

Madsen et al. (2014) recently developed a toolbox for obtaining homogenously functionalized sihcone elastomers by the use of a clickable chain extender (Fig. 3), which greatly facilitates the targeted formulation of silicone elastomers in modular fashion, as illustrated in Fig. 4. The chloro-functional intermediate in scheme X furthermore was shown to simultaneously increase the dielectric permittivity and decrease the dielectric loss of the resulting silicone elastomers. These initial results indicate that a sensitive balance of certain properties such as elastic moduli, permittivity, dielectric loss, conductivity, and electrical breakdown is required to optimize the electromechanical response for DBAs. However, with the recent developments reported for silicone elastomers, an increasing number of DBA-targeted properties can be more fully developed. 

V. Yu. Kramarenko, T. A. Shantalii, I. L. Karpova, K. S. Dragan, E. G. Privalko, V. P. Privalko, D. Fragiadakis, P. Pissis (2004) Polyimides reinforced with the sol-gel derived oigano-silicon nanophase as low dielectric permittivity materials, Polym. Adv. Technol., in press. 

The parameter of concern for the polymer measurements was the dielectric tan delta, defined as the dielectric loss modulus divided by the dielectric permittivity. To create a baseline for the system, a clean silicon wafer was analyzed the tan delta values were reported in Figure 4.4-2. 

Liquid insulators are required for circuit breakers, transformers, and some cable applications. Natural hydrocarbon mineral oils are commonly-used, as well as chlorinated aromatic liquids (desirable because of nonflammability). For high-temperature situations, silicone fluids may be used. Permittivities range between 2 and 7. Insulating liquids function both as electrical insulators and heat-transfer media. See also Dielectric Theory. 

A thin layer (approximately 10 mil thick) of RTV silicone was coated on the Micromet mini-dielectric sensor. The RTV silicone was first cured at room temperature, then in an oven at 120 C for a period of time, similar to certain RTV production cure schedules. The permittivity and loss factor of the RTV silicone were recorded during this cure cycle. 

Ferroelectrics are high dielectric materials that are easily polarized in an electric field and can remain polarized to some degree after the field is removed. Such properties make them ideal candidates for computer memory applications and they have been used in the form of thin films as ferroelectric random access memories (FeRAMs) and as high permittivity dielectrics for Dynamic Random Access Memory DRAMs. They have also been looked at as a replacement for silicon dioxide in certain MOS applications. 

As an example, we estimate the resonance enhancement of an intraband optical transition in silicon carbide (SiC) nanociystals. The dielectric function of SiC is well modeled by the expressions (7) with = 6.52, Qt = 793.9 cm" (and the wavelength At = 12.6 pm), = 970.1 cm (Al = 10.3 pm), and y = 4.763 cm. Note that the relaxation parameter y is much less than the optical phonon frequencies, y/Qi = 0.006 and y/ L = 0.005. The solution of the resonance condition (6) results in Q w 902cm and the corresponding resonance wavelength A 11 pm. Here and hereafter, in all onr numerical estimates we accept the permittivity of a host matrix Shost = 2.25, because this value is typical for many solvents, glasses, and polymers. Then, the gain factor G(Q) is estimated to be approximately 3.6 x 10. ... 

The Shockley equations describe a linear dependence between drain current and permittivity of the gate dielectric. In order to lower the supply voltage of OFETs, silicon nitride was examined because its permittivity Cnitride 8 is almost twice as large as that of silicon dioxide. Moreover, with a roughness of 1-2 nm rms it has the smoothest surface of the chemical vapour deposited dielectrics, which is one essential requirement for the growth of a well-ordered pentacene film. 

One of the simplest approaches relies on the realisation of composite materials by filling an ordinary elastomer with a highly dielectric component (e. g. ceramics), it is possible to obtain a resulting material showing the combination of the advantageous matrix elasticity and filler permittivity. As an example, promising results have been obtained with a silicone elastomer mixed with a titanium dioxide powder [284]. 

Low and stable values of dissipation factor and permittivity under varying temperatures and also varying frequency became apparent when electronic applications for silicones were first developed over 30 years ago. Von Hippel measured very stable values of dielectric characteristics for silicone resin and silicone resin bonded glasscloth laminates at temperatures up to 200°C and at frequencies from 100 Hz to 100 MHz... 

Benshmane MY, Khl H, Tryson MJ (2010b) Dielectric electro-active polymer push actuators performance and challenges. Polym Int 59 415-421 Biggs J, Danielmeier K, Hitzbleck J et al (2013) Electroactive polymers developments of and perspectives for dielectric elastomers. Angew Chem Int Ed 52 9409-9421 Bose H, Uhl D, Rabindranath R et al (2012) Novel DEA with organically modified silicone elastomer for permittivity enhancement Proc SPIE 8340 83402E Brochu P, Pei Q (2010) Advances in dielectric elastomers for actuators and artificial muscles. Macromol Rapid Commun 31 10-36... 

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