Self-healing block copolymer films - from mechanistic understanding towards applications in coatings and membranes

该合作项目的重点是制备具有自我修复能力的(可逆性)交联嵌段共聚物膜，并将其作为纳米结构涂层或先进功能膜材料的概念验证应用。作为实现自我修复特性的策略，我们通过呋喃和马来酰亚胺单元之间的Diels-Alder(DA)化学，采用随温度变化的共价交联。在自愈应用中使用嵌段共聚物和部分三嵌段三元共聚物是解决此类材料固有问题的一种可能性：平滑和动态链段的组合具有强大和可逆的网络形成能力。我们已经证明，侧链上含有马来酰亚胺和呋喃单元的统计共聚物以及含有聚(呋喃缩水甘油醚)(PFGE)链段的嵌段共聚物是这类应用的潜在候选者。通过该项目，我们将这一初步研究扩展到三嵌段共聚物和三嵌段三元共聚体系(ABA和ABC)，特别是具有两个可独立交联的链段的体系(例如，通过聚二烯的UV交联和PFGE的DA化学)或存在两个互补动机的体系(ABA*-内在交联剂作为添加单独交联剂的替代)。此外，当我们处理嵌段共聚物时，我们针对的是一种回转形态，以生成不同链段之间具有高内部界面的材料，并评估其对自愈合特性的影响。此外，嵌段序列(ABA*与AA*B)或交联剂类型的变化将使我们能够更深入地了解潜在的机制。由此产生的嵌段共聚物膜将在第一次研究中用作纳米孔膜的选择性分离层或作为亲水-疏水涂层，例如，防止生物污染。

This cooperation project focuses on the preparation of (reversibly) crosslinked block copolymer films with self-healing capabilities and their proof-of-concept application as nanostructured coatings or in advanced functional membrane materials. As strategy to implement self-healing characteristics, we employ temperature-dependent covalent crosslinking via Diels-Alder (DA) chemistry between furan and maleimide units. The use of block copolymers and, in parts, triblock terpolymers, in self-healing applications is one possibility to address one of the inherent problems in such materials: The combination of smooth and dynamic segments with the capability of strong and reversible network formation. We have already demonstrated that statistic copolymers containing maleimides and furan units in the side chain as well as block copolymers containing poly(furfuryl glycidyl ether) (PFGE) segments represent promising candidates for such applications. With this project, we expand this preliminary studies to triblock copolymer and triblock terpolymer architectures (ABA and ABC), in particular systems which feature two segments which can be independently crosslinked (e.g., by UV crosslinking of polydienes and DA chemistry of PFGE) or where two complementary motives are present (ABA* - intrinsic crosslinking as an alternative for the addition of a separate crosslinker). Furthermore, as we deal with block copolymers which have the ability to undergo phase separation in the bulk into different morphologies, we target a gyroid morphology to generate materials with a high internal interface between unlike segments and to evaluate the effects on the self-healing characteristics. In addition, variations of the block sequence (ABA* vs. AA*B) or the type of crosslinker will allow to gain deeper insights into the underlying mechanism. The so-generated block copolymer films will be employed in first studies as selective separation layer in nanoporous membranes or as hydrophilic-hydrophobic coatings, e.g., to prevent biofouling.