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UID:20251119T051504EST-3405dlMUw0@132.216.98.100
DTSTAMP:20251119T101504Z
DESCRIPTION:Metamaterials describe a class of materials in which material p
 roperties arise from the interaction of electromagnetic waves with the sub
 -wavelength sized component structures that constitute them. It has become
  clear that producing nano-based materials with properties not found in na
 ture\, such as metamaterials active at optical frequencies\, requires brea
 kthroughs in the ability to position materials with nanometer precision. T
 his desire has led to a growing interest in bottom-up\, self-assembling sy
 stems. In this talk\, I will discuss recent developments in two approaches
  to self-assembly of plasmonic nanoparticles.\n\nOne such approach is to u
 se ligands that can trigger self-assembly. We demonstrate that 14-nm silve
 r nanoparticles can quickly and spontaneously self-assemble into highly an
 isotropic structures in solution using controlled amounts of one of three 
 short ditopic ligands: cysteamine\, DTT or cysteine. The self-assembled ch
 ain-based structures are bound together through hydrogen bonding\, making 
 them reasonably robust over a wide range of solution conditions and temper
 atures. The degree of self-assembly\, and thus the resulting optical prope
 rties can be readily dictated by the ligand concentration\, pH and solvent
 . The highly anisotropic spectra are reminiscent of high aspect ratio 1D n
 anoparticles such as rods\, and have not been previously demonstrated to t
 his extent with silver nanoparticles.\n\nAnother such approach is to use b
 iomolecules as scaffolds because of the specificity and versatility they p
 rovide. In particular\, the use of viruses as nanoscale scaffolds offers t
 he promise of exquisite control for positioning on the nanoscale\, using a
  particle that can undergo further self-assembly into extended structures\
 , and allowing the simultaneous creation of many identical complex submicr
 on geometrical structures. We use the TMVcp (Tobacco Mosaic Virus coat pro
 tein) command surface to grow and assemble silver nanoparticles. The versa
 tility of TMV allows the formation of continuous in addition to rings of d
 iscrete nanoparticles that are characterized by UV-vis and TEM. TEM clearl
 y showed the formation of the rings composed of an average of 5-6 nanopart
 icles per ring as well as a central nanoparticle under appropriate pH cond
 itions. Discrete Dipole Approximation of AgNPs rings excited by plane wave
  incident field shows plasmon broadening and red-shift in agreement with t
 he experimental measurements. Our silver rings are believed to be the smal
 lest to date\, and they can offer a testing material for existing theories
 .\n
DTSTART:20161122T180000Z
DTEND:20161122T191500Z
LOCATION:Room 10\, Maass Chemistry Building\, CA\, QC\, Montreal\, H3A 0B8\
 , 801 rue Sherbrooke Ouest
SUMMARY:ChemSoc Seminar: Dr. Amy Blum - Self-assembled Plasmonic Nanostruct
 ures 
URL:/chemistry/channels/event/chemsoc-seminar-dr-amy-b
 lum-self-assembled-plasmonic-nanostructures-264105
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