nanopatterns – understanding emergence of properties at scale
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Nanopatterns – Understanding Emergence of Properties at
Scale
Robert D. Cormia & Jill N. Johnsen
Foothill College
Overview
• Nanoscience => the big ideas
• Emergence => the missing idea
• Nanopatterns => a new rubric
• Examples => nanopatterns in use
• Future directions and practice
Nanoscience – Big Ideas
• 2006 workshops
• NCLT and SRI
• University of Michigan and Northwestern University
• Eight big ideas
• A textbook guide
The Big Ideas
• Size and scale
• Matter
• Dominant Forces
• Properties are size dependent
• Models
• Tools
• Technology and society
• Self assembly
The Big Ideas in Nanoscale Science and Engineering Stevens, Sutherland, Schank, & Krajcik, (2007). Collaboration of NCLT, Northwestern University and SRI, in a series of workshops, (culminating in August 2006 in San Luis Obispo)
The Missing Idea
• Emergence of properties at scale
• We talk about it all the time
• But no one ever explains it
• Because……
Emergence is a very difficult topic to talk about!
Emergence Model
Archetype
Properties
Process
System
Process evolutionArc
hety
pe B
ehav
iors
System processSystem Archetype
System Constituents Actor Interactions
Class
prop
ertie
s
Archetype process
Syst
em P
rope
rties
Syst
em b
ehav
iors
Primitive interactions
Emergent Properties
Size Dependent Properties“Molecular Dynamics (MD) simulations of heat transfer based on classical statistical mechanics allow the atom to have thermal heat capacity through kT energy. Here k is Boltzmann’s constant and T absolute temperature. The above picture shows melting temperatures applied on the left with the right maintained at freezing. The simulation is discreted and submicron. But lacking periodicity, MD solutions of discrete nanostructures are invalid by QM. Here QM stands for quantum mechanics. Unlike statistical mechanics, QM forbids atoms in discrete submicron nanostructures to have heat capacity, and therefore the nanostructure cannot conserve EM energy by an increase in temperature. Without temperature changes, thermal conduction is precluded at the nanoscale.”
Melting point is an emergent property
Validity of Heat Transfer by Molecular Dynamics - http://www.nanoqed.org/
Size Dependent Properties:Ni nanoparticles => Nanomagnetism
http://www.grin.com/en/doc/231229/size-dependent-magnetic-properties-
http://www.flickr.com/photos/brookhavenlab/3191719900/in/photostream
Phonon Network
http://en.wikipedia.org/wiki/Phonon Images Wikipedia commons
Nanopatterns
• Network archetypes• Memorizing patterns, vs. structures• Patterns of atoms in structural networks• Atoms as nodes, each with atomic orbitals
=> focus on bonding networks• Network archetypes => nanosystems
– Smaller motifs, that expand into systems
Nanopatterns Rubric
• Networks of atoms• Systems of physics• Emergence of
properties at scale
• Draw network of atoms for a structural system
• Sketch out the chemical bonding / orbital network
• Look at the extended structure as a system
http://en.wikipedia.org/wiki/Pi_bond
Graphene Nanostructure
Extended sp2 hybridized carbon and p-p* network
Graphene as a System
Nanostructures and Nanosystems from carbon nano-motifs
nanostructure Nano-motif (or structural unit) Nanopattern Nanosystem
Graphene/graphite sp2 moiety bracket graphene hexagon Extended plane
Fullerene sp2 moiety cap hexagon/pentagon Enclosed sphere
Nanotube sp2 moiety mesh zigzag/armchair mesh Enclosed tube
Nanoonion sp2 moiety (ring?) zigzag/armchair swirl? Nanospheres?
Boron nitride nanomesh Trigonal BN BN hexagonal ring Planar honeycomb
Self Assembled Monolayers alkane (head and tail) 1-2 dimensional SAM 2 dimensional sheet
Liposomes phospholipid unit Phospholipid bilayer Spherical bilayers
Dendrimers g-0 functional branch Fractal branch (G-x)Spherical/functionalized macro-molecule
Allotropes of carbon
A - diamondB - graphiteC - lonsdaleiteD - C60 Buckminsterfullerene
E - Amorphous carbonF - C70
G - C540
H - single-walled carbon nanotube
http://en.wikipedia.org/wiki/Allotropes_of_carbon
Nano-OnionNano onion is a proposed structure for graphene which wraps itself into larger spheres and then into chains. The mechanism for forming the spheres is not known, but might be influenced by the chirality of the nanocarbon network, i.e., the armchair/zigzag m/n ratio. This factor can be measured in Raman G band (as G- and G+), and additionally in solid state 13C NMR. Nano-onion is an example of an extended nanostructure becoming a nanosystem, and having levels of unfolding complexity at scales of tens, hundreds, and thousands of Angstroms. The ability to ‘tune’ the chirality of the graphene networks, and alter the unfolding structure at the mesoscale, is one of the goals of combining the nanopatterns rubric with PNPA.
Borazine Nanomesh
• Borazine decomposition
• Forms ordered surface network
• One layer thick (like graphene)
• Extended structure• Emergent properties
http://en.wikipedia.org/wiki/Nanomesh
Borazine Nanomesh
Networks of atoms in novel nanoscale structures
“Dancing Triangles' are formed by sulfur atoms on a layer of copper, which in turn rests upon a base, or 'substrate' of ruthenium. Scientists at Brookhaven Lab will study this type of configuration to understand how metal behaves on top of another. Layered metals are often used as catalysts, such as those that clean pollutants from automobile exhaust in catalytic converters.”
Flickr Brookhaven Laboratory Stream http://www.flickr.com/photos/brookhavenlab/3191719710/in/photostream/
Nanostructures
• Small networks of atoms– Liposomes– Dendrimers– Carbon nanotubes– Self Assembled Monolayers– Unit cells of extended
nanostructured materials• Graphene• Nanomesh
Each phospholipid is a structural motif, a structure in itself, and a building block in a larger system
A system of phospholipids that is an emergent structure itself. Liposomes and cellular vessicles
http://en.wikipedia.org/wiki/Exosome_(vesicle)
http://en.wikipedia.org/wiki/Phospholipid
Nanosystems
Summary / References• Nanopatterns rubric
Networks of atomsSystems of physicsEmergence of properties at scale
• Nanostructures => nanosystems• The Big Ideas in Nanoscale Science and Engineering
Stevens, S. Y., Sutherland, L., Schank, P., & Krajcik, J. (2007).– http://www.mcrel.org/Nanoteach/pdfs/big_ideas.pdf
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