viscous polymer
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Author(s):  
Bumjun Park ◽  
Christiana Oh ◽  
Sooyoun Yu ◽  
Bingxin Yang ◽  
Nosang Vincent Myung ◽  
...  

Abstract As the energy storage markets demand increased capacity of rechargeable batteries, Li metal anodes have regained major attention due to their high theoretical specific capacity. However, Li anodes tend to have dendritic growth and constant electrolyte consumption upon cycling, which lead to safety concerns, low Coulombic efficiency, and short cycle life of the battery. In this work, both conductive and non-conductive 3D porous hosts were coupled with a viscous (melt) polymer electrolyte. The cross-section of the hosts showed good contact between porous hosts and the melt polymer electrolyte before and after extensive cycling, indicating that the viscous electrolyte successfully refilled the space upon Li stripping. Upon deep Li deposition/stripping cycling (5 mAh cm-2), the non-conductive host with the viscous electrolyte successfully cycled, while conductive host allowed rapid short circuiting. Post-mortem cross-sectional imaging showed that the Li deposition was confined to the top layers of the host. COMSOL simulations indicated that current density was higher and more restricted to the top of the conductive host with the polymer electrolyte than the liquid electrolyte. This resulted in quicker short circuiting of the polymer electrolyte cell during deep cycling. Thus, the non-conductive 3D host is preferred for coupling with the melt polymer electrolyte.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6288
Author(s):  
Mirella Ramirez ◽  
Louis Vaught ◽  
Chiu Law ◽  
Jacob L. Meyer ◽  
Rani Elhajjar

Dielectric elastomers (DE) are novel composite architectures capable of large actuation strains and the ability to be formed into a variety of actuator configurations. However, the high voltage requirement of DE actuators limits their applications for a variety of applications. Fiber actuators composed of DE fibers are particularly attractive as they can be formed into artificial muscle architectures. The interest in manufacturing micro or nanoscale DE fibers is increasing due to the possible applications in tissue engineering, filtration, drug delivery, catalysis, protective textiles, and sensors. Drawing, self-assembly, template-direct synthesis, and electrospinning processing have been explored to manufacture these fibers. Electrospinning has been proposed because of its ability to produce sub-mm diameter size fibers. In this paper, we investigate the impact of electrospinning parameters on the production of composite dielectric elastomer fibers. In an electrospinning setup, an electrostatic field is applied to a viscous polymer solution at an electrode’s tip. The polymer composite with carbon black and carbon nanotubes is expelled and accelerated towards a collector. Factors that are considered in this study include polymer concentration, solution viscosity, flow rate, electric field intensity, and the distance to the collector.


2021 ◽  
Vol MA2021-02 (1) ◽  
pp. 97-97
Author(s):  
Bumjun Park ◽  
Sooyoun Yu ◽  
Jiacheng Liu ◽  
Nosang V. Myung ◽  
Jennifer L. Schaefer

2021 ◽  
Author(s):  
Sergey Tikhomirov ◽  
Fedor Bakharev ◽  
Andrey Groman ◽  
Alexander Kalyuzhnyuk ◽  
Yulia Petrova ◽  
...  

Abstract One of the motivations for EOR methods is the possible instability of the front between phases with high contrast of mobility. Highly viscous polymer slug partially solves the problem by stabilizing the front between water and oil. During further water displacement viscous fingers might appear on the rear end of the slug, and their breakthrough might reduce the oil recovery factor. In the paper we study the size of the mixing zone on the rear end of the slug and further the development of the graded viscosity banks technology (GVB or tapering) to reduce the volume of used polymer without loss of effectiveness.


Author(s):  
MD Khalil ◽  
Bashir Khoda

Abstract A thin viscous layer is found over a substrate when it is immersed in a polymer solution. The layer thickness depends on the polymer and solvent type, their volume fraction, and the substrate. If the liquid solution contains particles, they are entrapped on the viscous polymer layer, acting as the binder. The trade-off between the viscous force and the centrifugal force on the particle determines the entrapment. Furthermore, the size of entrained particles are dictated by the binder concentration of the solution., A particle filtration technique is presented using the entrapment phenomenon from a poly-disperse mixture. A dimensionless number called the entrapment factor is introduced to correlate the particle entrapment with various parameters. By changing the entrapment factor, three distinct entrapment regimes are achieved and explained from a poly-disperse mixture. The experimental result shows that entrapped particles become larger as the factor increases, which can be controlled with multiple parameters of the dipping process. The proposed technique can lead to a filtration process of the wide-range poly-disperse particle mixture over the capillary filtration processes.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1836
Author(s):  
Antonio Gavalás-Olea ◽  
Antje Siol ◽  
Yvonne Sakka ◽  
Jan Köser ◽  
Nina Nentwig ◽  
...  

There is an increasing interest in algae-based raw materials for medical, cosmetic or nutraceutical applications. Additionally, the high diversity of physicochemical properties of the different algal metabolites proposes these substances from microalgae as possible additives in the chemical industry. Among the wide range of natural products from red microalgae, research has mainly focused on extracellular polymers for additive use, while this study also considers the cellular components. The aim of the present study is to analytically characterize the extra- and intracellular molecular composition from the red microalga Dixoniella grisea and to evaluate its potential for being used in the tribological industry. D. grisea samples, fractionated into extracellular polymers (EPS), cells and medium, were examined for their molecular composition. This alga produces a highly viscous polymer, mainly composed of polysaccharides and proteins, being secreted into the culture medium. The EPS and biomass significantly differed in their molecular composition, indicating that they might be used for different bio-additive products. We also show that polysaccharides and proteins were the major chemical compounds in EPS, whereas the content of lipids depended on the separation protocol and the resulting product. Still, they did not represent a major group and were thus classified as a potential valuable side-product. Lyophilized algal fractions obtained from D. grisea were found to be not toxic when EPS were not included. Upon implementation of EPS as a commercial product, further assessment on the environmental toxicity to enchytraeids and other soil organisms is required. Our results provide a possible direction for developing a process to gain an environmentally friendly bio-additive for application in the tribological industry based on a biorefinery approach.


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