Ko Kyujin, Yang Su-Chul
Department of Chemical Engineering (BK21 FOUR), Dong-A University, Busan 49315, Korea.
Polymers (Basel). 2020 Nov 5;12(11):2601. doi: 10.3390/polym12112601.
In the last decade, particulate matter (PM) has gradually become a serious public health issue due to its harmful impact on the human body. In this study, we report a novel filtration system for high PM capturing, based on the magnetoelectric (ME) effect that induces an effective surface charge in membrane filters. To elucidate the ME effect on PM capturing, we prepared electrospun poly(vinylidene fluoride)(PVDF)/CoFeO(CFO) membranes and investigated their PM capturing efficiency. After electrical poling under a high electric field of 10 kV/mm, PM-capturing efficiencies of the poled-PVDF/CFO membrane filters were improved with carbon/fluorine(C/F) molar ratios of C/F = 4.81 under = 0 and C/F = 7.01 under = 700 Oe, respectively. The result illustrates that electrical poling and a dc magnetic field could, respectively, enhance the surface charge of the membrane filters through (i) a strong beta-phase alignment in PVDF (poling effect) and (ii) an efficient shape change of PVDF/CFO membranes (magnetostriction effect). The diffusion rate of a water droplet on the PVDF/CFO membrane surface is reduced from 0.23 to 0.05 cm/s by covering the membrane surface with PM. Consequently, the PM capturing efficiency is dramatically improved up to 175% from ME membranes with the poling process and applying a magnetic field. Furthermore, the PM was successfully captured on the prototype real mask derived from the magnetoelectric effect induced by a permanent magnet with a diameter of 2 cm without any external power.
在过去十年中，颗粒物（PM）因其对人体的有害影响已逐渐成为一个严重的公共卫生问题。在本研究中，我们报告了一种基于磁电（ME）效应的新型高效PM捕获过滤系统，该效应可在膜过滤器中诱导产生有效表面电荷。为阐明ME效应在PM捕获方面的作用，我们制备了电纺聚偏二氟乙烯（PVDF）/钴铁氧体（CFO）膜，并研究了它们的PM捕获效率。在10 kV/mm的高电场下进行电极化后，极化后的PVDF/CFO膜过滤器在 = 0时C/F摩尔比为4.81、在 = 700 Oe时C/F摩尔比为7.01的情况下，PM捕获效率分别得到了提高。结果表明，电极化和直流磁场可分别通过以下方式增强膜过滤器的表面电荷：（i）PVDF中强烈的β相取向（极化效应）和（ii）PVDF/CFO膜的有效形状变化（磁致伸缩效应）。用PM覆盖PVDF/CFO膜表面后，水滴在膜表面的扩散速率从0.23降至0.05 cm/s。因此，通过极化过程和施加磁场，ME膜的PM捕获效率显著提高了175%。此外，在没有任何外部电源的情况下，PM成功地捕获在了由直径为2 cm的永磁体诱导的磁电效应衍生出的原型实际口罩上。
