Department of Chemistry , Rutgers University-Newark , 73 Warren Street , Newark , New Jersey 07102 , United States.
J Am Chem Soc. 2019 Oct 9;141(40):15963-15971. doi: 10.1021/jacs.9b07452. Epub 2019 Sep 26.
Classical Lewis pairs (LPs) between unhindered electron-poor Lewis acids (LAs) and electron-rich Lewis bases (LBs) present an overlooked motif with tremendous potential as dynamic cross-links in transient polymer networks (TPNs) for self-healing and stimuli-responsive applications. We demonstrate that simple and intuitive matching of weak/strong organoborane LA and amine LB pairs offers access to a large set of binding equilibrium constants, , that span ∼6 orders and dissociation rate constants, , that span ∼7 orders of magnitude. The implementation in polystyrene (PS)/polydimethylsiloxane (PDMS) blends results in dynamically cross-linked networks with bulk thermomechanical properties that are directly correlated with the strength and kinetic parameters for the LP interactions. The LP dynamic cross-link design is highly versatile and broadly applicable to different polymer architectures as demonstrated in the formation of reprocessable elastomers from Lewis base-decorated high molecular weight PDMS in combination with Lewis acid-decorated PS when reinforced with fumed silica as a filler.
经典路易斯酸碱对（LPs）之间存在一种被忽视的模式，其中未受阻碍的电子缺路易斯酸（LAs）和富电子路易斯碱（LBs）作为瞬态聚合物网络（TPNs）中的动态交联点，具有巨大的潜力，可用于自修复和刺激响应应用。我们证明，简单直观地匹配弱/强有机硼 LA 和胺 LB 对，可以获得一系列大的结合平衡常数 K b ，其跨度约为 6 个数量级，以及离解速率常数 k d ，其跨度约为 7 个数量级。在聚苯乙烯（PS）/聚二甲基硅氧烷（PDMS）共混物中的实施导致动态交联网络具有体热机械性能，其与 LP 相互作用的强度和动力学参数直接相关。LP 动态交联设计具有高度的通用性，可广泛应用于不同的聚合物结构，如在路易斯碱修饰的高分子量 PDMS 与路易斯酸修饰的 PS 形成可再加工弹性体时得到证明，当用气相二氧化硅作为填料增强时。
