Conformation of Tunable Nanocylinders: Up to Sixth-Generation Dendronized Polymers via Graft-Through Approach by ROMP

• DOI: 10.1021/acs.macromol.9b00457
• Publication Date: 2019-04-23T13:19:50Z
• Authors: Fabien Dutertre; Ki-Taek Bang; Emmanouil Vererou...; Benoit Loppinet; Sanghee Yang; Sung-Yun Kang; George Fytas; Tae-Lim Choi
• Keywords: ROMP; Norbornene; Ring-opening metathesis polymerisation; Hydrodynamic radius; Dispersity

Well-defined dendronized polymers (denpols) bearing high-generation dendron are attractive nano-objects as high persistency provides distinct properties, contrast to the random coiled linear However, their syntheses via graft-through approach have been very challenging due structural complexity and steric hindrance retarding polymerization. Here, we report first example of synthesis poly(norbornene) (PNB) containing ester dendrons up sixth generation (G6) by ring-opening metathesis This is highest ever polymerized among prepared approach, producing denpols with molecular weight 1960 kg/mol. Combination size-exclusion chromatography, light scattering, neutron scattering allowed a thorough study these large in dilute solution. A semiflexible cylinder model was successfully applied represent both static dynamic experimental quantities yielding persistent length (lp), cross-sectional radius (Rcs), contour (L). The denpol seemed increase generation, lp reaching 27 nm (Kuhn 54 nm) for PNB-G6, demonstrating rod-like conformation. Poly(endo-tricycle[4.2.2.0]deca-3,9-diene) (PTD) exhibited larger than PNB analogues same presumably higher grafting density PTD denpols. As dendritic side chains introduce shape anisotropy into backbone, future work will entail systems concentrated solutions melts.