(Lecture) From Molecules to Polymers: Insights on Molecular Packing, Conformation, and Dynamics from Solid-State NMR

Topic: From Molecules to Polymers: Insights on Molecular Packing, Conformation, and Dynamics from Solid-State NMR

Speaker: Prof. Michael Ryan Hansen （Westfälische Wilhelms-Universität Münster）

Time: November 12, 2018 (Monday) 14:45

Venue: 324 lecture hall, No. 2 building, North Science Park, Wushan Campus

Abstract

Molecules and polymers with extended π-conjugation, such as low-band-gap π-conjugatedpolymers and disc-shaped aromatic molecules, have the potential to serve as efficient organicsemiconductors in various electronic devices. A common feature shared by both of thesematerial classes is that their specific function is established via solution processing, resultingin active materials that are semi crystalline, which lack long-range ordering. This prevents thedirect access to details about the molecular organization from a conventional approach.

In my talk I will outline a general strategy for determining the molecular packing of molecules and polymers with extended π-conjugation that combines X-ray diffraction and solid state NMR experiments with quantum-chemical calculations of Nucleus Independent ChemicalShift (NICS) maps.This combination provides a useful platform to assess specific packingmotifs, which in some cases even allow setting up a crystal structure provided that sufficientconstraints can be derived from experiments. The potential of the proposed strategy will beexemplified by recent work on poly-3-alkyl-thiophenes (P3ATs),donor-acceptor-typepolymers,and shape-persistent macrocycles, forming empty helical nanochannels.Finally,I will illustrate how site-specific information about molecular dynamics determined from solidstate NMR experiments can be used to elucidate structure and complex motions in discoticliquid crystals.

Biography

Michael Ryan Hansen was born in 1976 and received his PhD from Aarhus University, Denmark, in 2006 for his work on quadrupolar nuclei in heterogeneous catalysis and inorganic materials characterized by solid-state NMR and DFT calculations. In 2007 he joined the group of Prof. Hans Wolfgang Spiess at the Max Planck Institute for Polymer Research (MPI-P) in Mainz, Germany, as a Carlsberg Foundation Postdoctoral Research Fellow. He was appointed research group leader at the MPI-P in 2010, with emphasis on organic supramolecular systems. From 2013-2015 he was an Assistant Professor at Aarhus University, Denmark, supported by a Young Investigator Grant from the Villum Foundation, Denmark. Since June 2015 he is a Professor of Physical Chemistry at the Westfälische Wilhelms-Universität Münster, Germany. His current scientific interests focus on soft matter systems and energy-related materials studied by solid-state NMR spectroscopy to elucidate their nanoscale assembly and molecular dynamics.

Announced by South China Advanced Institute for Soft Matter Science and Technology