Milkin Pavel, Danzer Michael, Ionov Leonid
Faculty of Engineering Sciences, University of Bayreuth, Ludwig Thoma Str. 36A, Bayreuth, 95447, Germany.
Chair of Electrical Energy Systems, University of Bayreuth, Universistätsstr. 30, Bayreuth, 95447, Germany.
Macromol Rapid Commun. 2022 Oct;43(19):e2200307. doi: 10.1002/marc.202200307. Epub 2022 May 15.
Self-healing polymer-carbon composites are seen as promising materials for future electronic devices, which must be able to restore not only their structural integrity but also electrical performance after cracking and wear. Despite multiple reports about self-healing conductive elements, there is a lack of a broad fundamental understanding of correlation between viscoelasticity of such composites, their electrical properties, and self-healing of their mechanical as well as electrical properties. Here, it is reported thorough investigation of electromechanical properties of blends of carbon black (CB) as conductive filler and viscoelastic polymers (polydimethylsiloxanes (PDMS) and polyborosiloxane (PBS)) with different relaxation times as matrices. It is shown that behavior of composites depends strongly on the viscoelastic properties of polymers. Low molecular polymer composite possesses high conductivity due to strong filler network formation, quick electrical, and mechanical properties restoration, but for this the ability is sacrificed to flow and ductility at large deformation (material is brittle). In contrary, high relaxation time polymer composite behaves elastically on small time and flows at large time scale due to weak filler network and can heal. However, the electrical properties are worse than that of carbon and viscous polymer and degrade with time.
自修复聚合物-碳复合材料被视为未来电子设备的有前途的材料，这类材料不仅必须能够在开裂和磨损后恢复其结构完整性，还能恢复其电性能。尽管有许多关于自修复导电元件的报道，但对于这类复合材料的粘弹性、电性能以及机械和电性能的自修复之间的相关性，仍缺乏广泛而深入的理解。在此，本文报道了对以炭黑（CB）作为导电填料、以具有不同弛豫时间的粘弹性聚合物（聚二甲基硅氧烷（PDMS）和聚硼硅氧烷（PBS））作为基体的共混物的机电性能进行的深入研究。结果表明，复合材料的行为强烈依赖于聚合物的粘弹性。低分子聚合物复合材料由于形成了强大的填料网络，具有高导电性，电性能和机械性能能快速恢复，但为此牺牲了在大变形下的流动和延展性（材料易碎）。相反，高弛豫时间聚合物复合材料在短时间内表现出弹性，由于填料网络较弱，在长时间尺度下会流动且能够自修复。然而，其电性能比碳和粘性聚合物的电性能差，并且会随时间退化。
