Spring 2015 Seminars
|January 12, 2015||GPS 101||Kent Ridl|
|January 19, 2015||Martin Luther King, Jr. Day|
|January 26, 2015|
The Emerging Role of Network Analysis in Physics Education
|February 2, 2015||Void formation in crosslinked polymer networks||Aaron Feickert|
|February 9, 2015||How Fluid Flow Affects Phase-Separation Front Formed Morphologies||Eric Foard|
<Presidents' Day> Infectious diseases, auto-immune diseases, and opportunities for biophysics
|February 23, 2015||Bruce Rafert|
|March 2, 2015||APS March Meeting|
|March 9, 2015||TBA||Yen Lee Loh|
|March 16, 2015||Spring Break!!|
|March 23, 2015||TBA||Alec Habig|
|March 30, 2015|
|April 1, 2015||<Special Day and Location!!>Structure, Dynamics and Properties of Block Polymer Dispersions||Frank S. Bates|
|April 6, 2015||Spring Recess|
April 13, 2015
|April 20, 2015||TBA||Alfredo Alexander-Katz|
|April 24, 2015||<Special Day!!>TBA||Christos Likos|
|April 27, 2015|
|May 4, 2015||TBA||Jessica Striker|
|May 5, 2015||<Special Day and Location!!>A Robust Nonlinear Block Copolymer Nanoreactor-Based Strategy to Monodisperse Hairy Nanocrystals with Precisely Controlled Dimensions, Compositions and Architectures||Zhiqun Lin|
|May 11, 2015||Exam Week!|
How Fluid Flow Affects Phase-Separation Front Formed Morphologies
Dept. Physics, NDSU
Monday, February 9, 2015, 3:00-4:00pm.
221 South Engineering
We previously studied the highly ordered morphologies generated in the wake of an idealized, abrupt, phase-separation front moving with an imposed velocity through a diffusive binary material. We found such a system in two dimensions will form ordered lamelle oriented either parallel or orthogonal with respect to the front, and regular hexagonal droplet arrays, with the favored morphology dependent upon volume fraction and phase-separation front speed. in three dimensions we find additional ordered cylindrical phases.
In this talk I explore what effect hydrodynamics has on the orthogonal lamella phase. We find that, even at high viscosities, the effect of hydrodynamic flow is significant, and occur for reasons that may surprise you.
Infectious diseases, auto-immune diseases, and opportunities for biophysics
Gerard C. L. Wong
Bioengineering Dept., Chemistry & Biochemistry Dept.,
California NanoSystems Institute
Monday, February 16, 2015, 3:00-4:00pm, Refreshments at 2:30.
221 South Engineering
We present examples from our group where biophysics impacts unsolved medical problems. We start with bacterial biofilms, which are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. The first step in biofilm formation, adaptation to life on a surface, requires the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting tracking algorithms from colloid physics, we dissect bacterial social behavior at the single cell level. We will also discuss how we can learn from innate immunity peptides, and renovate antibiotic design via the biophysics of peptide-membrane interactions. Finally, we examine the pathological role of antimicrobial peptides in autoimmune diseases.
Structure, Dynamics and Properties of Block Polymer Dispersions
Dr. Frank S. Bates
Regents Professor and Head, Department of Chemical Engineering and Materials Science, University of Minnesota
<Special Time!!>Wednesday, April 1, 2015, 3:00-4:00pm (refreshments served 2:30).
<Special Location!!>271 Batcheller Technology Center
Block copolymers belong to a broad class of amphiphilic compounds that includes soaps, lipids and nonionic surfactants. These macromolecules assemble into micelles with molecular dimensions on the order of 5 to 50 nm in size when mixed with excess solvent that preferentially solvates one block type. This presentation will explore two different aspects of block copolymer micelle formation. The fundamental thermodynamic and kinetic factors that control micelle shape and dynamics will be discussed based on small-angle x-ray and neutron scattering (SAXS and SANS) experiments and cryogenic transmission and scanning electron microscopy results. Although the structural features displayed by amphiphilic block copolymers resemble those associated with the self-assembly of lipids and simple surfactants (e.g., spherical and cylindrical micelles and vesicles) a macromolecular architecture leads to remarkably different dynamic properties, linked to a vanishingly small critical micelle concentration. As a consequence, molecular exchange is rapidly extinguished with increasing molecular weight resulting in non-ergotic behavior. These concepts have been exploited in developing a recently commercialized technology that provides immense improvements in the fracture toughness of thermosetting epoxy plastics, which also will be described.
A Robust Nonlinear Block Copolymer Nanoreactor-Based Strategy to Monodisperse Hairy Nanocrystals with Precisely Controlled Dimensions, Compositions and Architecture.
Dr. Zhiqun Lin
Professor, School of Materials Science and Engineering, Georgia Institute of Technology
<Special Time!!> Tuesday, May 5, 2015, 3:00-4:00pm (Refreshments will be served at 2:30).
<Special Location!!>271 Bachellor Technology Center
Nanocrystals exhibit a wide range of unique properties (e.g., electrical, optical, and optoelectronic) that depend sensitively on their size and shape, and are of both fundamental and practical interest. Breakthrough strategies that will facilitate the design and synthesis of a large diversity of nanocrystals with different properties and controllable size and shape in a simple and convenient manner are of key importance in revolutionarily advancing the use of nanocrystals for a myriad of applications in lightweight structural materials, optics, electronics, photonics, optoelctronics, magnetic technologies, sensory materials and devices, catalysis, drug delivery, biotechnology, and among other emerging fields. In this talk, I will elaborate a general and robust strategy for crafting a large variety of functional nanocrystals with precisely controlled dimensions (i.e., plain, core/shell, and hollow nanoparticles) by capitalizing on a new class of unimolecular star-like block copolymers as nanoreactors. This strategy is effective and able to produce organic solvent-soluble and water-soluble monodisperse nanoparticles, including metallic, ferroelectric, magnetic, luminescent, semiconductor, and their core/shell nanoparticles, which represent a few examples of the kind of nanoparticles that can be produced using this technique. The applications of these functional nanocrystals in energy-related applications (i.e., solar cells and photocatalysis) will also be discussed.