Contributions of hard and soft blocks in the self-healing of metal-ligand-containing block copolymers
Contributions of hard and soft blocks in the self-healing of metal-ligand-containing block copolymers
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DOI：
10.1016/j.eurpolymj.2017.06.020
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发表时间：
2017-08
影响因子：
6
通讯作者：
R. Bose;Marcel Enke;A. Grande;S. Zechel;F. Schacher;M. Hager;S. García;U. Schubert;S. Zwaag
中科院分区：
文献类型：
--
作者：
R. Bose;Marcel Enke;A. Grande;S. Zechel;F. Schacher;M. Hager;S. García;U. Schubert;S. Zwaag
本工作的主要目的是研究含金属配体的嵌段共聚物的硬嵌段和软嵌段各自对自修复行为的贡献。为此，采用可逆加成-断裂链转移（RAFT）聚合法合成了不同结构的三联吡啶嵌段共聚物。这些嵌段共聚物由作为硬嵌段的聚苯乙烯、作为软嵌段的丙烯酸正丁酯（BA）和作为置于软嵌段中的不同位置的配体部分的三联吡啶单元组成。这些嵌段共聚物与氯化锰（II）络合，以引入瞬时交联，从而产生自修复行为。还合成并测试了仅具有硬嵌段和软嵌段的均聚物。使用硝酸镍（II）进行准不可逆交联（i.e.by）以研究永久（强）交联网络的动力学。生成流变学主曲线，从而能够确定这些网络中的终端流和超分子相互作用的可逆性。此外，宏观划痕愈合行为和分子的运动性的聚合物链在这些超分子网络进行了研究。划痕愈合的动力学研究进行，以确定流变松弛和宏观划痕愈合的温度依赖性的相似性。在我们以前的工作中，我们已经探索了可逆的金属-配体相互作用的强度的效果和改变硬软嵌段的比例的效果。这项工作进一步分离的硬和软块以及可逆的相互作用的个人贡献，并揭示其在划痕愈合的复杂现象的相对重要性。
The main aim of this work is to study the respective contribution of the hard and soft blocks of a metal-ligand containing block copolymer to the self-healing behavior. To this aim, different block copolymers containing terpyridine were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. These block copolymers consisted of polystyrene as the hard block,n-butyl acrylate (BA) as soft block and terpyridine units as the ligand moiety placed at different locations in the soft block. These block copolymers were complexed with manganese(II) chloride to introduce transient crosslinks and, thus, self-healing behavior. Homopolymers with the hard and soft block only were also synthesized and tested. A quasi-irreversible crosslinking,i.e.by using nickel(II) nitrate, was performed in order to study the dynamics of the permanently (strongly) crosslinked network. Rheological master curves were generated enabling the determination of the terminal flow in these networks and the reversibility of the supramolecular interactions. Additionally, the macroscopic scratch healing behavior and the molecular mobility of the polymer chains in these supramolecular networks were investigated. A kinetic study of the scratch healing was performed to determine the similarities in temperature dependence for rheological relaxations and macroscopic scratch healing. In our previous work, we have explored the effect of strength of the reversible metal-ligand interaction and the effect of changing the ratio of hard to soft block. This work goes further in separating the individual contributions of the hard and soft blocks as well as the reversible interactions and to reveal their relative importance in the complex phenomenon of scratch healing.