Refine
Has Fulltext
- no (172)
Year of publication
Document Type
- Article (172) (remove)
Is part of the Bibliography
- yes (172) (remove)
Keywords
- piezoelectret (3)
- piezoelectrets (3)
- Curie transition (2)
- Electrets (2)
- Ferroelectrets (2)
- P(VDF-TrFE-CFE) terpolymer (2)
- charge-carrier transport (2)
- chemical modification (2)
- dielectric barrier discharge (DBD) (2)
- dielectric properties (2)
- dielectric relaxation spectroscopy (2)
- ferroelectret (2)
- fluoroethylenepropylene (FEP) copolymer (2)
- mid-temperature transition (2)
- piezoelectricity (2)
- sensors and actuators (2)
- space-charge stability (2)
- surface treatment (2)
- (PEDOT (1)
- (high-)voltage measurements (1)
- 3D printing (1)
- Annealing (metallurgy) (1)
- Cellular polypropylene (PP) (1)
- Curie-transition (1)
- Dielectric Relaxation Spectroscopy (DRS) (1)
- Dielectric hysteresis (1)
- Differential Scanning Calorimetry (DSC) (1)
- Doping (1)
- Electric potential (1)
- Epoxy resin (1)
- Epoxy resins (1)
- Ferroelectret (1)
- Ferroelectric polarization (1)
- Ferroelectric polymer (1)
- Forcemyography (1)
- High-impact polystyrene (1)
- Hysteresis (1)
- Insulators (1)
- Memory device (1)
- Mid-temperature transition (1)
- Non-linear dielectric spectroscopy (1)
- Organic FeFET (1)
- Organic TFT (1)
- P(VDF-TFE) copolymer (1)
- P(VDF-TrFE-CFE) (1)
- PSS)-coated porous (1)
- Phase transitions (1)
- Polarization (1)
- Polymer-dispersed liquid crystal (1)
- Relaxor-ferroelectric (RF) fluoropolymers (1)
- Relaxor-ferroelectric polymer (1)
- Surface treatment (1)
- Trapped charges (1)
- acoustic transducers (1)
- acoustic-transducer materials (1)
- all-organic (1)
- all-organic ferroelectret nanogenerator (FENG) (1)
- calibration (1)
- charge storage (1)
- crosslinking (1)
- crystalline phases (1)
- dielectric (1)
- dielectric barrier discharges (1)
- dielectric hysteresis (1)
- dielectric polarisation (1)
- dielectric relaxation (1)
- dielectric resonance spectroscopy (1)
- dielectrics (1)
- differential scanning calorimetry (1)
- dipole grafting (1)
- durability (1)
- effective polarization (1)
- elastomers (1)
- electret polymers (1)
- electret stability (1)
- electrets (1)
- electric sensing devices (1)
- electrical breakdown (1)
- electrical polarization hysteresis (1)
- electro-mechanical transducers (1)
- electro-mechanically active polymers (1)
- electrostatic (1)
- equivalent-circuit (1)
- expanded polytetrafluoroethylene (1)
- experiments (1)
- fabric electrodes (1)
- ferro- and piezoelectrets (1)
- ferroelectric polymer (1)
- ferroelectric polymers (1)
- ferroelectric thin films (1)
- ferroelectricity and piezoelectricity in polymers (1)
- film (1)
- film sensor (1)
- flashover (1)
- fluorinated ethylene-propylene copolymer (FEP) (1)
- frequency response (1)
- functional materials (1)
- haptic feedback (1)
- injection (1)
- intermolecular force (1)
- liquid crystal alignment (1)
- low-density polyethylene (1)
- man-made dipole (1)
- micro-energy harvesting (1)
- mid-temperature transition(s) (1)
- modelling (1)
- motion registration (1)
- multi-layer systems (1)
- multiple (1)
- nanocomposite (1)
- nanofiber (1)
- permittivity enhancement (1)
- piezoelectric measurements (1)
- piezoelectric nanogenerator (PENG) (1)
- piezoelectric polymers (1)
- piezoelectricity-polarization relation (1)
- poly(vinylidenefluoride-trifluoroethylene) P(VDF-TrFE) (1)
- polyethylene (1)
- polyethylene naphthalate (PEN) (1)
- polymer ferroelectrets (1)
- polymer films (1)
- polymer-foam films (1)
- polymers (1)
- polytetrafluoroethylene (PTFE) (1)
- printed electroacoustic thin-film transducers (1)
- printing (1)
- processing (1)
- pyroelectric polymers (1)
- pyroelectricity (1)
- relationships (1)
- relaxor-ferroelectric polymer (1)
- relaxor-ferroelectric polymers (1)
- remanent polarisation (1)
- screen (1)
- screen-printed (1)
- silicone based dielectric elastomer actuators (1)
- soft electro-active materials (1)
- soft matter (1)
- space charge (1)
- spectroscopy (1)
- spin coating (1)
- static-pressure dependence (1)
- stretching (1)
- structure-property (1)
- surface charge (1)
- surface morphology (1)
- surface reconstruction (1)
- surface-roughened (1)
- systems (1)
- temperature dependence (1)
- thermal (1)
- thermally stimulated depolarization current (1)
- thin-film actuators (1)
- titanium dioxide (1)
- tubular-channel polymer systems (1)
- vinylidenefluoride (VDF)-based polymers (1)
- vinylidenefluoride(VDF)-based polymers (1)
- wearable (1)
- wearable electronics (1)
Institute
The zeta potential of the motile spores of the green alga (seaweed) Ulva linza was quantified by video microscopy in combination with optical tweezers and determined to be -19.3ñ1.1 mV. The electrostatic component involved in the settlement and adhesion of spores was studied using electret surfaces consisting of PTFE and bearing different net charges. As the surface chemistry remains the same for differently charged surfaces, the experimental results isolate the influence of surface charge and thus electrostatic interactions. Ulva spores were demonstrated to have a reduced tendency to settle on negatively charged surfaces and when they did settle the adhesion strength of settled spores was lower than with neutral or positively charged surfaces. These observations can be ascribed to electrostatic interactions.
Zerstörungsfreie Tomographie von Raumladungs- und Polarisationsverteilungen mittles Wärmepulsen
(2007)
Non-destructive, three-dimensional imaging of space-charge and polarization distributions in electret materials has been implemented by means of laser-induced thermal pulses. In pyroelectric films of poled poly(vinylidene fluoride), images of up to 45 x 45 pixels with a depth resolution of less than 0.5 mu m and a lateral resolution of 40 mu m were recorded, the latter being limited by fast thermal diffusion in the absorbing metallic front electrode. Initial applications include the analysis of polarization distributions in corona-poled piezoelectric sensor cables and the detection of patterned space-charge distributions in polytetrafluoroethylene films.
Voided space-charge electrets : piezoelectric transducer materials for electro-acoustic applications
(2004)
A double-layer transcrystalline polypropylene (PP) film with a flat central interface layer between its two transcrystalline layers is obtained by recrystallization from the melt between two polytetrafluoroethylene (PTFE) surfaces on both sides of the PP film. Its electret properties are studied and compared with those of a single-layer transcrystalline PP film re-crystallized in contact with only one PTFE surface. Within experimental uncertainty, the two types of transcrystalline films exhibit the same thermal properties and crystallinities. After thermal poling, however, two hetero-charge layers of opposite polarity are found on the internal interfaces of the double-layer transcrystalline films and may together be considered as micrometer-sized dipoles. The unexpected phenomenon does not occur in single-layer transcrystalline samples without a central interface layer, suggesting that the interfaces between the transcrystalline layers and the micrometer-thick central interface layer may be the origin of deeper traps rather than the crystalline structures in the transcrystallites or the spherulites. The origin of the interfacial charges was also studied by means of an injection-blocking charging method, which revealed that intrinsic charge carriers introduced during recrystallization are most likely responsible for the interfacial charges. It is fascinating that a material as familiar as PP can exhibit such intriguing properties with a special bipolar space-charge polarization across the central interface layer after quasi-epitaxial surface moulding into a double-layer transcrystalline form. In addition to applications in electret (micro-)devices for electro-mechanical transduction, the highly ordered structures may also be employed as a new paradigm for studying charge storage and transport in polymer electrets and in dielectrics for DC electrical insulation.
In cellular, electromechanically active polymer films, the so-called ferroelectrets, the cell size and shape distributions can be varied through a controlled inflation process. Up to now, high-pressure treatments were usually performed at elevated temperatures. There are, however, significant experimental limitations and complications if the pressure and temperature treatments are performed at the same time. Here, we demonstrate the controlled inflation of cellular polypropylene films by means of sepal-ate pressure and temperature treatments. Separate procedures are Much easier to implement. Excellent electromechanical properties were achieved with Such a two-step inflation process. The technique has significant potential for inflating large-area transducer films for electromechanical and electroacoustical applications