Nonlinear dielectric spectroscopy

The dielectric response of biological tissue has long been assumed linear. Thus an enzyme is treated as a hard sphere which relaxes linearly in an a. c. field at all but high field strengths [128]. In a suspension of cells, the electric field cannot penetrate to the interior of the cell at the low frequencies currently of interest in nonlinear dielectric spectroscopy [129], and is dropped almost entirely across the outer membrane of the cell which is predominantly capacitive at these frequencies, as was shown in Fig. 4. 

This is the case of nonlinear, i.e. nonlinear dielectric spectroscopy related, relaxation time. 

Bias-induced reverse piezoelectric response Broadband dielectric spectroscopy (BDS) Dielectric permittivity spectrum Dielectric resonance spectroscopy Elastic modulus Ferroelectrets Electrical breakdown Acoustic method Characterization Dynamic coefficient Interferometric method Pressure and frequency dependence of piezoelectric coefficient Profilometer Quasistatic piezoelectric coefficient Stress-strain curves Thermal stability of piezoelectricity Ferroelectric hysteresis Impedance spectroscopy Laser-induced pressure pulse Layer-structure model of ferroelectret Low-field dielectric spectroscopy Nonlinear dielectric spectroscopy Piezoelectrically generated pressure step technique (PPS) Pyroelectric current spectrum Pyroelectric microscopy Pyroelectricity Quasistatic method Scale transform method Scanning pyroelectric microscopy (SPEM) Thermal step teehnique Thermal wave technique Thermal-pulse method Weibull distribution... 

The particular choice of the authors was rather to put emphasis on experimental techniques that are either specifically relevant or powerfiil with respect to ferroelectric polymers and fenoelectrets or represent recent experimental developments and trends. In this sense, room was given to nonlinear dielectric properties that can be probed by nonlinear dielectric spectroscopy and various types of hysteresis experiments. Besides a systematic description of piezoelectric and inverse piezoelectric techniques, we have added dielectric resonance spectroscopy as an all-round approach yielding elastic, piezoelectric, and dielectric properties of polymer electrets in a single dielectric measurement. 

To date, a number of chemically selective near-field imaging methods have been demonstrated. Near-field contrast mechanisms that rely on electronic spectroscopy (UV-visible absorption and fluorescence),204 vibrational spectroscopy (IR absorption and Raman spectroscopies), dielectric spectroscopy (microwave dispersion), and nonlinear spectroscopy (second harmonic generation) have all been demonstrated at length scales well below the diffraction limit of light. 

Hillenbrand J, Sessler GM (2004) Quasistatic and dynamic piezoelectric coefficients of polymer foams and polymer film systems. Dielectr Electr Insul IEEE Trans 11 72-79 Kremer F, Schonhals A (2002) Broadband dielectric spectroscopy. Springer, Berlin Kressmann R (2001a) Linear and nonlinear piezoelectric response of charged cellular polypropylene. J Appl Phys 90 3489-3496... 

The FEBS technique utihzes the electric and optical anisotropies of molecules dissolved in the solution. When the external electric field is applied to a solution containing molecules with the anisotropic polarizability, the molecules tend to be oriented in the direction of the applied electric field. If moreover the molecules have the optical anisotropy, the solution exhibits the birefringence, which is called the Kerr effect [171] as a nonlinear optical effect. In the FEBS, where the sinusoidal electric field is applied, the Kerr constants are measured by varying the frequency/ of the sinusoidal wave. In this sense, the FEBS closely resembles the dielectric relaxation spectroscopy [172]. 

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