Effect of Molecular Weight and Layer Thickness on the Dielectric Breakdown Strength of Neat and Homopolymer Swollen Lamellar Block Copolymer Films
Effect of Molecular Weight and Layer Thickness on the Dielectric Breakdown Strength of Neat and Homopolymer Swollen Lamellar Block Copolymer Films
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分子量和层厚度对纯均聚物溶胀层状嵌段共聚物薄膜介电击穿强度的影响
DOI：
10.1021/acsapm.0c00127
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发表时间：
2020
影响因子：
5
通讯作者：
Apata, Ikeoluwa
中科院分区：
文献类型：
--
作者：
Samant, Saumil;Basutkar, Monali;Singh, Maninderjeet;Masud, Ali;Grabowski, Christopher A.;Kisslinger, Kim;Strzalka, Joseph;Yuan, Guangcui;Satija, Sushil;Apata, Ikeoluwa
设计下一代轻量化脉冲功率器件取决于了解影响介电材料储能性能的因素。聚合物介质薄膜的能量存储与电压击穿强度呈二次依赖关系，提高击穿强度的策略有望产生高能量存储密度的途径。高度分层的层状嵌段共聚物（L-BCP）模型聚苯乙烯-b-聚甲基丙烯酸甲酯（PS-b-PMMA）薄膜与无序铸态的L-BCP薄膜相比，击穿电压（EBD）提高了约50%（储存能量密度增加225%，U ~ EBD2）。使用非晶聚合物的能量密度与工业标准的半晶双轴取向聚丙烯（BOPP）相当，并且是该领域的一个显着发展。这项工作加深了对L-BCP薄膜中febd增强的分子机制的理解，将ebd与分子量（Mn）直接联系起来，并解释了链端密度和分布、界面形成、层厚及其相对贡献的影响。铸态无序L-BCP薄膜由于膜中均匀分布的链端增加，与均聚物的研究相似，随着mn的降低，ebd也随之降低。在平行有序的L-BCP膜中，由于界面的形成和链端空间隔离形成分离区，ebd显著增加。我们进一步证实了链端在击穿过程中的作用，将低mn - bcp与匹配的mn均聚物混合，以获得与高mn的整齐L-BCP相同的层间距。在低均聚物组分下，由于湿刷状态下肿胀有序L-BCP域内的净链端密度增加，ebd显著下降，其次是由于过量均聚物形成分离的“相间层”，导致层厚增加，从而导致debd增加。值得注意的是，由于均聚物的整体不利链端贡献，EBDof均聚物膨胀的l - bcp始终低于相同结构域间距的纯l - bcp。这些发现为设计下一代具有高能量密度固态BCP薄膜电容器的柔性电子器件提供了重要的l -BCP选择规则。
Designing next-generation lightweight pulsed power devices hinges on understanding the factors influencing the energy storage performance of dielectric materials. Polymer dielectric films have a quadratic dependence of energy storage on the voltage breakdown strength, and strategies to enhance the breakdown strength are expected to yield a path toward high energy storage densities. Highly stratified lamellar block copolymer (L-BCP) films of model polystyrene-b-polymethylmethacrylate (PS-b-PMMA) exhibited as much as ∼50% enhancement in breakdown voltage (EBD) (225% increase in stored energy density,U∼EBD2) compared to unordered as-cast L-BCP films. Such an energy density using amorphous polymer is on par with industry-standard semicrystalline biaxially oriented polypropylene (BOPP) and as such a notable development in the field. This work develops a deeper understanding of the molecular mechanisms ofEBDenhancement in L-BCP films, relatingEBDdirectly to molecular weight (Mn), with interpretation to effects of chain-end density and distribution, interface formation, layer thickness, and their relative contributions. As-cast disordered L-BCP films show decreasingEBDwith decreasingMnsimilar to homopolymer studies because of the increase of homogeneously distributed chain ends in the film.EBDincreases significantly in parallel ordered L-BCP films because of the combination of interface formation and spatial isolation of the chain ends into segregated zones. We further confirm the role of chain ends in the breakdown process blending a lowMnL-BCP with matchedMnhomopolymers to attain the same layer spacing as neat L-BCP of higherMn.EBDshows a significant decrease at low homopolymer fractions because of increased net chain-end density within swollen ordered L-BCP domains in wet-brush regime, followed by increasedEBDbecause of layer thickness increase via segregated “interphase layer” formation by excess homopolymers. Notably,EBDof homopolymer swollen L-BCPs is always lower than that of neat L-BCPs of the same domain spacing because of overall adverse chain-end contribution from homopolymers. These findings provide important selection rules for L-BCPs for designing next-generation flexible electronics with high energy density solid-state BCP film capacitors.
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影响因子：
5.5
作者：
MAYES, AM;JOHNSON, RD;MAJKRZAK, CF
通讯作者：
MAJKRZAK, CF
影响因子：
2.5
作者：
Jiang, Zhang;Li, Xuefa;Wang, Jin
通讯作者：
Wang, Jin
影响因子：
3
作者：
M. Wolak;A. Wan;J. Shirk;M. Mackey;A. Hiltner;E. Baer
通讯作者：
E. Baer
影响因子：
4.6
作者：
Ahn, Hyungju;Lee, Yonghoon;Ryu, Du Yeol
通讯作者：
Ryu, Du Yeol
影响因子：
3.4
作者：
Choi, Seunghoon;Kim, Eunhye;Russell, Thomas P.
通讯作者：
Russell, Thomas P.