Huang, Y.-W.Y.-W.HuangLin, Y.-C.Y.-C.LinLi, J.-S.J.-S.LiWEN-CHANG CHENCHU-CHEN CHUEH2022-03-222022-03-22202120507534https://www.scopus.com/inward/record.uri?eid=2-s2.0-85112627200&doi=10.1039%2fd1tc02116h&partnerID=40&md5=14c66f43b6b6f0a4a965e1bcf8e7d0f7https://scholars.lib.ntu.edu.tw/handle/123456789/598119Aldol reaction is a green approach that is exclusively suitable for developing conjugated polymers (CPs) with ladder-type structures. Herein, electron-deficient non-fused and fused bis-isoindigo (bis-IID) are copolymerized with axisymmetric thiophene (T) or centrosymmetric thieno[3,2-b]thiophene (TT) electron-rich spacers through Aldol polycondensation to prepare four donor-acceptor (D-A) CPs with ladder-type structures. The non-fused (P1andP2) and fused (P3andP4) bis-IIDs on the backbone lead to varied conformational flexibility that dominates aggregation, energy levels, and packing of the polymers.P3andP4with a planar backbone exhibit a stronger aggregation and lower bandgap (1.38 eV) thanP1andP2(?1.8 eV), while their intense non-crystalline aggregation also results in an amorphous structure. Meanwhile, the configurational differences arising from axisymmetric T unit (P1andP3) and centrosymmetric TT unit (P2andP4) spacers is shown to deeply affect the surface morphology and film ductility. The non-planar backbone endowsP1andP3with low surface roughness and high brittleness. The combined low conformation and configuration regularity account for the inferior mobility ofP1. On the contrary,P2-P4exhibit comparable hole mobility ranging from 10?2-10?3cm2V?1s?1and up to 0.011 cm2V?1s?1(P2), due to their better regularity in both conformation and configuration. Collectively, our results provide a new perspective for designing new D-A CPs through Aldol polycondensation. ? The Royal Society of Chemistry 2021.Condensation reactionsFracture mechanicsHole mobilityKetonesLaddersMorphologyPolycondensationShimsSurface morphologySurface roughnessThiopheneAldol reactionsAmorphous structuresConformation and configurationConformational flexibilityDonor-acceptor conjugated polymersElectron-deficientLadder-type structureLow surface roughnessConjugated polymers[SDGs]SDG7journal article10.1039/d1tc02116h2-s2.0-85112627200