Highlights
May 19, 2009
Harvard University
New Ordered Hierarchical Helical Assemblies
Boaz Pokroy, Sung H. Kang, L. Mahadevan, and Joanna Aizenberg
Mesoscale hierarchical helical structures with diverse functions are abundant in nature.
May 17, 2009
Brandeis University
Self-Limited Self-Assembly of Chiral Subunits
Yasheng Yang, Robert Meyer, Michael Hagan
A simple computational model demonstrates the assembly of self-limited filamentous bundles. The images are taken from dynamic Monte Carlo simulations in which chiral subunits spontaneously assemble under different interaction strengths and degrees of chirality. (a) Moderate interactions and moderate chirality reproducibly lead to a self-limited bundle with three layers of subunits, while stronger chirality (b) results in a self-limited two-layer bundle. (c) With strong interactions, frustration is relieved by defects, which enable the formation of branched networks and irregular bundles.
May 17, 2009
Brandeis University
Polymers Under Constraint
Phil Huang, Andy Ward, Zvonimir Dogic, Seth Fraden, Michael Hagan
fd virus is a polymeric virus 1 mm in length and 10 nm in diameter. We bind fluorescently labeled fd to 1 mm diameter polystyrene spheres creating a charged polymer stabilized colloid (hairy bead) and measure the interparticle potential using a double laser trap. We first measure the interaction energy of (a) bare beads and (b) then the hairy beads, seen here in fluorescence microscopy. (c) Electron micrograph of hairy beads. The repulsive energy of hairy beads is large when the beads are close.
May 17, 2009
Brandeis University
MRSEC / SCOPE
David Barett, Olin; Seth Fraden
During the academic year, F08 - S09, Olin undergraduates Sean Calvo, Caitlin Greeley, Stephani Gulbrandsen, and Leif Jentoft designed, built, and tested a flexible automated microscopy platform capable of imaging an area up to 100mm x 100mm with a resolution of 10 microns at 4.8 second per square mm. It reduces the cost of performing microfluidics research and increases the speed by allowing researchers to easily reconfigure and expand the system to their changing needs.
May 17, 2009
Brandeis University
Active Emulsion
Hector Gonzales, Irving Epstein, Seth Fraden, Bing Xu
Stabilized emulsions containing the oscillating Belousov - Zhabotinsky chemical reaction (BZ) show interesting dynamics. Each drop acts as an independent chemical clock. However, they chemically communicate and exhibit collective behavior. In (a) three photos of the same hexagonally packed 100 micron diameter BZ drops are shown 80 seconds apart. White corresponds to the oxidized state; black to reduced. The pattern is explained in (b); first all green drops are in the oxidized state, then all blue drops and finally all red drops.
May 17, 2009
Georgia Institute of Technology
Chemical Modification of Epitaxial Graphene
Elena Bekyarova, Mikhail E Itkis, Palanisamy Ramesh, Robert C Haddon University of California-Riverside Claire Berger, Michael Sprinkle, Walt A de Heer Georgia Institute of Technology
The ability to modify the electronic structure and properties of graphene is an important step towards the large scale fabrication of electronic devices based on graphene technology.
May 17, 2009
New York University
NYU MRSEC E&HR NYAS Outreach
Co-sponsored inaugural Gotham-Metro Condensed Matter Meeting
Student-led one-day conference in hard and soft matter physics held at the New York Academy of Sciences
Participating institutions: New York University, Columbia University, City College of New York, CUNY Staten Island, New Jersey Institute of Technology, Rutgers University, Princeton University, SUNY Stony Brook, and Yale University
More than 140 attendees
May 17, 2009
New York University
Making colloidal helices
a collaboration with Prof. J. Bibette at the ESPCI in Paris
Need microscopic swimmers for transport and mixing in micro- and nanofluidic devices.
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