Dielectric Elastomers for Direct Wind-to-Electricity Power Generation

2009 ◽  
Author(s):  
Paul Brochu ◽  
Wei Yuan ◽  
Han Zhang ◽  
Qibing Pei
Keyword(s):  
Mechanical Stability ◽  
Mechanical Energy ◽  
Polymer Network ◽  
Single Layer ◽  
Energy Conversion Efficiency ◽  
Operational Reliability ◽  
Dielectric Elastomer ◽  
Low Energy ◽  
Interpenetrating Polymer Network ◽  
Comparative Results

We present a universal dielectric elastomer energy generator that can be scaled to match the requirements of the energy source. The design couples mechanical energy directly into an out of plane deflection that deforms the film. Cycling the generator between high and low strain states while applying a bias electric field switches the device between high and low energy states; charge that is injected at low energy can then be extracted at a higher potential. We present an analysis of the energy generation capacity and mechanical stability of the device and demonstrate its scalability via a compact, low energy/low deflection device and a larger, higher energy device. We demonstrate the capability of generating approximately 40 mJ per cycle in a single layer device with an active elastomer volume of only 0.57 cm3 and a maximum observed energy conversion efficiency of over 55%. We use recently developed advances in dielectric elastomer technology including interpenetrating polymer network films and carbon nanotube electrodes to improve operational reliability and present comparative results that demonstrate an increase in lifetime by several orders of magnitude over prestrained VHB acrylic films with carbon grease electrodes.

scholarly journals Understanding cytoskeletal avalanches using mechanical stability analysis

2021 ◽  
Vol 118 (41) ◽  
pp. e2110239118
Author(s):  
Carlos Floyd ◽  
Herbert Levine ◽  
Christopher Jarzynski ◽  
Garegin A. Papoian
Keyword(s):  
Energy Release ◽  
Mechanical Stability ◽  
Mechanical Energy ◽  
Polymer Network ◽  
Normal Modes ◽  
Structural Response ◽  
Mechanical Instability ◽  
Cellular Environment ◽  
Non Gaussian

Eukaryotic cells are mechanically supported by a polymer network called the cytoskeleton, which consumes chemical energy to dynamically remodel its structure. Recent experiments in vivo have revealed that this remodeling occasionally happens through anomalously large displacements, reminiscent of earthquakes or avalanches. These cytoskeletal avalanches might indicate that the cytoskeleton’s structural response to a changing cellular environment is highly sensitive, and they are therefore of significant biological interest. However, the physics underlying “cytoquakes” is poorly understood. Here, we use agent-based simulations of cytoskeletal self-organization to study fluctuations in the network’s mechanical energy. We robustly observe non-Gaussian statistics and asymmetrically large rates of energy release compared to accumulation in a minimal cytoskeletal model. The large events of energy release are found to correlate with large, collective displacements of the cytoskeletal filaments. We also find that the changes in the localization of tension and the projections of the network motion onto the vibrational normal modes are asymmetrically distributed for energy release and accumulation. These results imply an avalanche-like process of slow energy storage punctuated by fast, large events of energy release involving a collective network rearrangement. We further show that mechanical instability precedes cytoquake occurrence through a machine-learning model that dynamically forecasts cytoquakes using the vibrational spectrum as input. Our results provide a connection between the cytoquake phenomenon and the network’s mechanical energy and can help guide future investigations of the cytoskeleton’s structural susceptibility.

scholarly journals Methods to Improve Energy Conversion Efficiency of Dielectric Elastomer Generators

2019 ◽  
Vol 804 ◽  
pp. 63-67
Author(s):  
Heng Tong Cheng ◽  
Zhen Qiang Song ◽  
Shijie Zhu ◽  
Kazuhiro Ohyama
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Input Voltage ◽  
Energy Conversion Efficiency ◽  
Stretch Ratio ◽  
Dielectric Elastomer ◽  
Conversion Performance ◽  
Ratio Range

Dielectric elastomer generators (DEGs) are based on the electromechanical response of the dielectric elastomer film sandwiched between the compliant electrodes on each side, which are capable of converting mechanical energy from diverse sources (e.g, ocean wave) into electrical energy. In essence, DEG is a voltage up-converter using mechanical energy to increase the electrical energy of the charge on a soft capacitor. We evaluated the effect of input voltage and the pre-stretch ratios on energy conversion efficiency of DEG. With a power supply of 2.2kV and pre-stretch ratio of 2, the maximum net electrical energy density and energy conversion efficiency in a single harvesting cycle were measured to be 413 J/kg and 15.8%, respectively. The experimental results showed that, with the higher input voltage and the larger stretch ratio range, higher the energy conversion performance of DEG can be achieved.

Preparation and Damping property Study of Styrene-Acrylic IPN/Mt Nano-composite Material

2011 ◽  
Vol 284-286 ◽  
pp. 382-386 ◽  
Author(s):  
Bo Hu ◽  
Ze Peng Zhang ◽  
Xiao Ming Liu ◽  
Ji Chu Zhang
Keyword(s):  
Layer Structure ◽  
Polymer Network ◽  
Single Layer ◽  
Mechanical Analysis ◽  
Interpenetrating Polymer Network ◽  
Nano Composite ◽  
Damping Property ◽  
Transmission Electron ◽  
New Material ◽  
Acrylate Monomers

In the emulsion system, styrene, acrylate monomers and montmorillonite (Mt) were used to prepare interpenetrating polymer network/montmorillonite (IPN/Mt) nano-composite. X-ray diffraction (XRD), transmission electron microscopy (TEM) and dynamic mechanical analysis (DMA) were used to characterize the structure and damping property of the new material. Results of XRD and TEM showed that the layer structure of Mt was destroyed and Mt dispersed in the polymer matrix by single layer. The result of DMA indicated that the damping property of Styrene-Acrylic IPN/Mt was much better than that of Styrene-Acrylic IPN. Damping value of the Styrene-Acrylic IPN/Mt was well improved and the maximum of tanδ increased from 0.621 to 0.739, with a broad damping domain ranging from -41°C to 140+°C. All these findings indicated that styrene-acrylate IPN /Mt nano-composite of broad damping temperature range and high damping value was successfully prepared.

scholarly journals Porous scaffolds with the structure of an interpenetrating polymer network made by gelatin methacrylated nanoparticle-stabilized high internal phase emulsion polymerization targeted for tissue engineering

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22544-22555
Author(s):  
Atefeh Safaei-Yaraziz ◽  
Shiva Akbari-Birgani ◽  
Nasser Nikfarjam
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Cell Growth ◽  
Polymer Network ◽  
Synthetic Polymers ◽  
Tissue Scaffolds ◽  
Interpenetrating Polymer Network ◽  
Porous Scaffolds ◽  
Promising Strategy ◽  
Internal Phase

The interlacing of biopolymers and synthetic polymers is a promising strategy to fabricate hydrogel-based tissue scaffolds to biomimic a natural extracellular matrix for cell growth.

scholarly journals Macroporous chitosan/methoxypoly(ethylene glycol) based cryosponges with unique morphology for tissue engineering applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pradeep Kumar ◽  
Viness Pillay ◽  
Yahya E. Choonara
Keyword(s):  
Tissue Engineering ◽  
Polymer Network ◽  
Three Dimensional ◽  
Hysteresis Loops ◽  
Interpenetrating Polymer Network ◽  
Morphological Data ◽  
Porous Scaffolds ◽  
Morphological Variations ◽  
Molecular Stability ◽  
The Matrix

AbstractThree-dimensional porous scaffolds are widely employed in tissue engineering and regenerative medicine for their ability to carry bioactives and cells; and for their platform properties to allow for bridging-the-gap within an injured tissue. This study describes the effect of various methoxypolyethylene glycol (mPEG) derivatives (mPEG (-OCH3 functionality), mPEG-aldehyde (mPEG-CHO) and mPEG-acetic acid (mPEG-COOH)) on the morphology and physical properties of chemically crosslinked, semi-interpenetrating polymer network (IPN), chitosan (CHT)/mPEG blend cryosponges. Physicochemical and molecular characterization revealed that the –CHO and –COOH functional groups in mPEG derivatives interacted with the –NH2 functionality of the chitosan chain. The distinguishing feature of the cryosponges was their unique morphological features such as fringe thread-, pebble-, curved quartz crystal-, crystal flower-; and canyon-like structures. The morphological data was well corroborated by the image processing data and physisorption curves corresponding to Type II isotherm with open hysteresis loops. Functionalization of mPEG had no evident influence on the macro-mechanical properties of the cryosponges but increased the matrix strength as determined by the rheomechanical analyses. The cryosponges were able to deliver bioactives (dexamethasone and curcumin) over 10 days, showed varied matrix degradation profiles, and supported neuronal cells on the matrix surface. In addition, in silico simulations confirmed the compatibility and molecular stability of the CHT/mPEG blend compositions. In conclusion, the study confirmed that significant morphological variations may be induced by minimal functionalization and crosslinking of biomaterials.

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