McCarty Logan S, Whitesides George M
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St., Cambridge, MA 02138, USA.
Angew Chem Int Ed Engl. 2008;47(12):2188-207. doi: 10.1002/anie.200701812.
This Review discusses ionic electrets: their preparation, their mechanisms of formation, tools for their characterization, and their applications. An electret is a material that has a permanent, macroscopic electric field at its surface; this field can arise from a net orientation of polar groups in the material, or from a net, macroscopic electrostatic charge on the material. An ionic electret is a material that has a net electrostatic charge due to a difference in the number of cationic and anionic charges in the material. Any material that has ions at its surface, or accessible in its interior, has the potential to become an ionic electret. When such a material is brought into contact with some other material, ions can transfer between them. If the anions and cations have different propensities to transfer, the unequal transfer of these ions can result in a net transfer of charge between the two materials. This Review focuses on the experimental evidence and theoretical models for the formation of ionic electrets through this ion-transfer mechanism, and proposes--as a still-unproved hypothesis--that this ion-transfer mechanism may also explain the ubiquitous contact electrification ("static electricity") of materials, such as organic polymers, that do not explicitly have ions at their surface.
其制备方法、形成机制、表征工具及其应用。驻极体是一种在其表面具有永久宏观电场的材料；该电场可源于材料中极性基团的净取向，或源于材料上的净宏观静电荷。离子驻极体是一种由于材料中阳离子和阴离子电荷数量不同而具有净静电荷的材料。任何在其表面或内部可接触到离子的材料都有可能成为离子驻极体。当这种材料与其他某种材料接触时，离子可以在它们之间转移。如果阴离子和阳离子具有不同的转移倾向，这些离子的不等量转移会导致两种材料之间的净电荷转移。本综述重点关注通过这种离子转移机制形成离子驻极体的实验证据和理论模型，并提出——作为一个尚未得到证实的假设——这种离子转移机制也可能解释诸如有机聚合物等表面没有明确离子的材料普遍存在的接触起电（“静电”）现象。
