Zehao Sun

All Publications

• ROMP of Macromonomers Prepared by ROMP: Expanding Access to Complex, Functional Bottlebrush Polymers JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Sun, Z., Liu, B., Ma, M., Alexander-Katz, A., Ross, C. A., Johnson, J. A. 2025: 3855-3865

  Abstract

  Graft-through ring-opening metathesis polymerization (ROMP) of norbornene-terminated macromonomers (MMs) prepared using various polymerization methods has been extensively used for the synthesis of bottlebrush (co)polymers, yet the potential of ROMP for the synthesis of MMs that can subsequently be polymerized by graft-through ROMP to produce new bottlebrush compositions remains untapped. Here, we report an efficient "ROMP-of-ROMP" method that involves the synthesis of norbornene-terminated poly(norbornene imide) (PNI)-based MMs that, following ROMP, provide new families of bottlebrush (co)polymers and "brush-on-brush" hierarchical architectures. In the bulk state, the organization of the PNI pendants drives bottlebrush backbone extension to enable rapid assembly of asymmetric lamellar morphologies with large asymmetry factors. Overall, this work expands the scope of complex macromolecular architectures and provides insights into the interplay of backbone rigidity and self-assembly that will guide future nanolithography applications.

  View details for DOI 10.1021/jacs.4c17151

  View details for Web of Science ID 001395919700001

  View details for PubMedID 39808775

• Parent B₂N₂-Perylenes with Different BN Orientations ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Zhang, P., Zeng, J., Zhuang, F., Zhao, K., Sun, Z., Yao, Z., Lu, Y., Wang, X., Wang, J., Pei, J. 2021; 60 (43): 23313-23319

  Abstract

  Introducing BN units into polycyclic aromatic hydrocarbons expands the chemical space of conjugated materials with novel properties. However, it is challenging to achieve accurate synthesis of BN-PAHs with specific BN positions and orientations. Here, three new parent B2 N2 -perylenes with different BN orientations are synthesized with BN-naphthalene as the building block, providing systematic insight into the effects of BN incorporation with different orientations on the structure, (anti)aromaticity, crystal packing and photophysical properties. The intermolecular dipole-dipole interaction shortens the π-π stacking distance. The crystal structure, (anti)aromaticity, and photophysical properties vary with the change of BN orientation. The revealed BN doping effects may provide a guideline for the synthesis of BN-PAHs with specific stacking structures, and the synthetic strategy employed here can be extended toward the synthesis of larger BN-embedded PAHs with adjustable BN patterns.

  View details for DOI 10.1002/anie.202108519

  View details for Web of Science ID 000695869900001

  View details for PubMedID 34431600

• Engineering Supramolecular Polymer Conformation for Efficient Carbon Nanotube Sorting. Small (Weinheim an der Bergstrasse, Germany) Gao, T. Z., Sun, Z., Yan, X., Wu, H., Yan, H., Bao, Z. 2020: e2000923

  Abstract

  Supramolecular polymer sorting is a promising approach to separating single-walled carbon nanotubes (CNTs) by electronic type. Unlike conjugated polymers, they can be easily removed from the CNTs after sorting by breaking the supramolecular bonds, allowing for isolation of electronically pristine CNTs as well as facile recycling of the sorting polymer. However, little is understood about how supramolecular polymer properties affect CNT sorting. Herein, chain stoppers are used to engineer the conformation of a supramolecular sorting polymer, thereby elucidating the relationship between sorting efficacy and polymer conformation. Through NMR and UV-vis spectroscopy, small-angle X-ray scattering (SAXS), and thermodynamic modeling, it is shown that this supramolecular polymer exhibits ring-chain equilibrium, and that this equilibrium can be skewed toward chains by the addition of chain stoppers. Furthermore, by controlling the stopper-monomer ratio, the sorting yield can be doubled from 7% to 14% without compromising the semiconducting purity (>99%) or properties of sorted CNTs.

  View details for DOI 10.1002/smll.202000923

  View details for PubMedID 32500637