澳门新葡亰,报告题目:From Molecules to Polymers: Insights on Molecular Packing,
Conformation, and Dynamics from Solid-State NMR报 告 人:Michael Ryan
Hansen教授(德国明斯特大学)时 间:2018年11月12日(星期一)14:45地
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.1,2This 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),3,4donor-acceptor-typepolymers,5-7and shape-persistent
macrocycles, forming empty helical nanochannels.8Finally,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.9,10报告人简介: Michael Ryan
Hansen,博士,德国明斯特大学(Westfälische Wilhelms-Universität
Planck Institute for Polymer Research)Hans

主 题:Lectures on Modern Approaches to the Physics and
PhysicalChemistry of Soft Matter主讲人:Prof. Kenneth S. Schweizer
(University of Illinois at Urbana-Champaign)地
Glassy Dynamics and Kinetic Arrest in Soft Matter and Materials
Science时 间:2018年11月7日(周三)10:00(Pedagogical
Introduction)和15:00(Research Seminar)第二讲 Dynamics and
Viscoelasticity of Entangled Synthetic and Biological Polymer Liquids时
Introduction)和15:00(Research Seminar)第三讲 Structure, Phase
Behavior, Dynamics and Mechanical Response in Polymer Nanocomposites时
of the spectacular slowing down of relaxation and mass transport in
glass-forming liquids of atoms, molecules, colloids, nanoparticles,
polymers and other materials over 14 or more orders of magnitude remains
a grand challenge. Moreover, many advanced materials employ amorphous
solids, and vitrification can frustrate the assembly of ordered
structures. In the first talk, I will present an introductory overview
of glassy dynamics from the liquid side describing both the qualitative
similarities and large quantitative differences between material classes
and even within a single class of compounds (e.g., polymers). The
physical ideas, assumptions and limitations of both venerable
phenomenological models and more modern approaches will be discussed. In
the second talk, I will present our new microscopic, force-based
predictive theoretical approach to activated relaxation and emergent
elasticity that can address both the physical and chemical aspects of
glassy dynamics and kinetic arrest for molecular, colloidal and
polymeric systems over the entire range of relevant temperatures and
relaxation times. Its generalization to thin films will be briefly
mentioned, followed by an in depth discussion of the technologically
important problem of penetrant diffusion in supercooled liquids and
glasses. Quantitative confrontation of our theories with experiments
will be presented throughout the talk. Finally, limitations of our
approach and key open questions will be discussed.第2讲内容简介:The
existence and dynamical consequences of topological entanglements
between strongly interpenetrating and sufficiently large and/or dense
macromolecules of diverse architectures (chains, rods, star-branched) is
a fascinating and unique phenomenon in polymer science which is also
highly relevant to cell biology. Its fundamental origin is the emergent
kinetic consequences of polymer connectivity and uncrossability. In the
first talk, I will give an introductory overview of the key features of
entangled dynamics, viscoelastic response and diffusion from an
experimental perspective. Classic models of unentangled and entangled
linear chain and rigid rod liquids will then be described and their
predictions compared with experiment. Though existing theories in
equilibrium have had many successes, they are highly phenomenological
and there remain multiple open fundamental issues especially under
strong deformation conditions crucial to polymer processing and internal
force mediated processes in biopolymer networks. In the second talk I
will present an overview of our recent theoretical work that aims to
develop a first principles, force-based, predictive statistical
dynamical theory for the quiescent (under isotropic, oriented and
confined conditions) and nonequilibrium (strained, stressed) behavior of
entangled flexible chain and rigid rod liquids. New predictions will be
described from a physical perspective along with quantitative
comparisons with experiment and simulation. Open and difficult questions
in the area of nonlinear rheology will be briefly discussed, and our
recent ideas for making progress sketched.第3讲内容简介:Polymer
nanocomposites (PNC) are typically hybrid organic-inorganic materials
that traditionally have combined rigid nanoparticles (diameters 5-200
nm) and flexible macromolecules to achieve unique properties. The
classic example is rubber reinforcement via filler particles which is of
central importance in the tire industry. However, the field has largely
been empirically driven. Over the past decade or two, major progress has
been made at formulating and addressing fundamental physical questions
concerning these multi-component materials which involve an
exceptionally broad range of time, length and energy scales. In the
first talk, I will present an overview of the general PNC problem and
selected recent contributions by experimentalists, simulators and
theorists that address mainly the question of phase behavior and
microstructure as a function of chemical and physical variables, and its
impact on dynamical properties. In the second talk, I will give an
overview of our theoretical efforts over the last decade which have
aimed to merge and extend ideas and methods from colloid and polymer
physics and physical chemistry to create new predictive and microscopic
statistical mechanical theories that address PNC multi-scale structure,
states of aggregation, phase separation, nanoparticle diffusion, glass
and gel formation, and how nanoparticles modify polymer entanglement
phenomena. The new physical ideas will be described along with model
calculations and quantitative comparisons with x-ray and neutron
scattering, diffusion, structural relaxation, and mechanical
measurements.主讲人简介:Ken Schweizer received a B.S. in physics from
Drexel University in Philadelphia, and a Ph.D. in physics from the
University of Illinois at Urbana-Champaign (UIUC) in 1981 working with
the theoretical physical chemist David Chandler. After a postdoc in
chemical physics at Bell Labs with Frank Stillinger, in 1983 he joined
the Materials Directorate at Sandia National Laboratories where he
learned about polymer and materials science. In 1991 he moved to UIUC
where he is presently the G. Ronald and Margaret H. Morris Professor of
Materials Science and Engineering, Professor of Chemistry, Professor of
Chemical and Biomolecular Engineering, and member of the Frederick Seitz
Materials Research Laboratory and the Beckman Institute for Advanced
Science and Technology. His research interests are centered on
developing, and applying to experiment, predictive microscopic
statistical mechanical theories of the structure, thermodynamics, phase
behavior, dynamics and rheology of diverse soft materials including
molecules, polymers, colloids and nanocomposites in the liquid,
suspension, crystal, liquid crystalline, thin film, rubber, gel and
glass states. Honors include the Dillon Medal, Polymer Physics Prize,
and Fellowship from the American Physical Society, the Joel Henry
Hildebrand Award in the Theoretical and Experimental Chemistry of
Liquids from the American Chemical Society, and the Drucker Eminent
Faculty Award and undergraduate and graduate teaching excellence and
student mentorship awards from UIUC.附件:无



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