室温に近い鉄電ポリマーの大きな電熱効果

Bret Neese¹, Baojin Chu, Sheng-Guo Lu

¹Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA.

Science (New York, N.Y.)

|August 9, 2008

まとめ

研究者らは,冷却用の極性ポリマーにおける電熱効果 (ECE) を調査した. 彼らは,P ((VDF-TrFE) と関連するポリマーで有意なECEを発見し,先進的な固体冷却技術の可能性を示しました.

科学分野:

マテリアルサイエンス材料科学
熱力学は熱力学である.
ポリマーサイエンスの科学

背景:

極性ポリマーに電場を適用すると,二極の順序が変化し,エントロピーの変化による冷却アプリケーションが可能になる可能性があります.
電熱効果 (ECE) は,電場の下での材料のエントロピーの変化によって引き起こされる固体冷却の有望な現象です.

研究の目的:

鉄電ポリマー,特にP ((VDF-TrFE) と関連する共ポリマーにおける電熱効果を調査する.
冷却用途でこれらの材料で達成可能な同熱エントロピー変化とアディアバティック温度変化を定量化するために.

主な方法:

ピロ電気係数と電熱効果を結びつけるマクスウェル関係を利用した.
実験的に測定されたECEは,鉄電性ポリ (ビニリデンフッ化物-トリフッ化エチレン) [P (VDF-TrFE) ]共ポリマーで測定された.
室温近くのECEのために,リラクサーフェロエレクトリックポリマー,P(VDF-TrFE-クロロフルオロエチレン) を調査しました.

主要な成果:

70°C以上のP ((VDF-TrFE) で大きな電熱効果を達成しました (鉄電-準電の移行の上).
55 J/kg·Kを超える同熱エントロピーの変化と12°C以上のアディアバティック温度変化が観察されました.
P ((VDF-TrFE-chlorofluoroethylene)) で室温近くで比較可能なECEを実証した.

結論:

P ((VDF-TrFE) のようなフェロ電気ポリマーは,冷却に適した有意な電熱効果を示しています.
Relaxorの鉄電気ポリマーは,室温の固体冷却アプリケーションの可能性を秘めています.
この研究は,効率的な熱管理のためのポリマーベースの電熱材料の有効性を強調しています.

さらに関連する動画

11:11

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Published on: May 2, 2016

10:40

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Published on: April 8, 2018

関連する概念動画

01:31

Ferromagnetism

Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...

01:31

Dielectric Polarization in a Capacitor

The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...

01:30

Paramagnetism

Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...

01:24

Electrochemical Systems

Electrochemical systems provide a fascinating insight into the dynamic interplay of charged species within various phases. One notable example is the interaction between a membrane permeable to K⁺ ions but not to Cl⁻ ions, separating an aqueous KCl solution from pure water. As K⁺ ions diffuse through the membrane, they generate net charges on each phase, leading to a potential difference between them.Similarly, when a piece of Zn is immersed in an aqueous ZnSO₄ solution, the Zn metal, composed...

01:28

Induced Electric Dipoles

A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...

01:28

Types Of Superconductors

A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...

関連する実験動画