The presence of a bulky peripheral wedge destabilizes the homo-assembly of an amide functionalized acceptor (A) monomer and thereby enables the formation of an alternating supramolecular copolymer with an amide appended donor (D) monomer via the synergistic effect of H-bonding and the charge-transfer (CT) interaction with a remarkably high K a of 31 000 M–1. In sharp contrast, H-bonding driven homo-polymers of A and D are formed by just replacing the bulky chains of the A monomer with linear hydrocarbons. By taking advantage of the clear difference in the critical temperature for the onset of the AA or DD homo-assemblies and DA co-assembly (T DA ≫ T AA or T DD), the supramolecular polymerization pathway of the NDI-monomer could be fully diverted from isodesmic to cooperative in the presence of a small amount of DAN which helped the in situ production of nucleating sites involving the D–A CT-complex at a relatively higher temperature and the subsequent chain growth at T AA following the nucleation-elongation model.
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机译:庞大的外围楔形物的存在使酰胺官能化的受体(A)单体的均相组装不稳定,从而能够通过氢键和氢键的协同作用与酰胺附加的供体(D)单体形成交替的超分子共聚物。电荷转移(CT)相互作用,其K a极高,为31–000 M -1 sup>。与之形成鲜明对比的是,通过仅用线性烃取代A单体的大链,即可形成A和D的H键驱动均聚物。通过利用AA或DD均聚物和DA共组装(TD DA≫ T AA或T DD)的临界温度的明显差异,NDI单体的超分子聚合途径可以完全在有少量DAN的情况下从等渗转变为合作态,这有助于在相对较高的温度下原位产生涉及D–A CT复合物的成核位点,并随后按照成核伸长模型在T AA处进行链增长。
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