Constructing Microcapacitor Network of Carbon Nanotubes in Polymer Blends via Crystallization-Induced Phase Separation toward High Dielectric Constant and Low Loss

• Published in: ACS applied materials & interfaces 2020-06, Vol.12 (23), p.26444-26454
• Main Authors: Mao, Hanjun, Liu, Dan-Feng, Zhang, Nan, Huang, Ting, Kühnert, Ines, Yang, Jing-Hui, Wang, Yong
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c04575

Tailoring the distribution of nanoparticles and further constructing effective microcapacitors in polymer blends are important issues for developing high performance polymer dielectric nanocomposites. The common method to control the selective localization of nanoparticles in an immiscible polymer blend is relatively rough and it easily results in the accumulation of nanoparticles in one component, which usually leads to the dramatic rising of the dielectric loss in the nanocomposites. In this work, a novel strategy based on step-by-step crystallization has been proposed to tailor the refined distribution and dispersion of carbon nanotubes (CNTs) in the melt-miscible blend poly(butylene succinate)/poly(vinylidene fluoride) (PBS/PVDF) through the crystallization-induced phase separation and the engineered interfacial affinity between CNTs and polymer components to acquire high dielectric constant and low dielectric loss. The results reveal that PBS is excluded along the growth of PVDF spherulites and locate in the margin areas of PVDF spherulites during the step-by-step crystallization process. And because of the higher interfacial interaction between CNTs and PBS, CNTs are located in the PBS rich domain, resulting in high concentration of CNTs in the inter-spherulites of PVDF. Thus, the dielectric constants of the nanocomposites are greatly improved by nearly 5~24 times compared with the nanocomposites achieved by quick cooling and simultaneously, the dielectric loss of the nanocomposites is still kept at low level. This work shows that the step-by-step crystallization method can be used to fabricate the nanocomposites with a synergistic increase in the dielectric performances due to the formation of the refined microcapacitor assembly. To the best of our knowledge, this is the pioneering report that the dielectric constant of the nanocomposites can be greatly enhanced just through crystallization-optimized distribution and dispersion of CNTs in the immiscible polymer blends, and it possibly gives new technical route for the fabrication of the advanced dielectric composites.