U.S. National Science Foundation
We Can Figure This Out.org
Resources: The Need for Self-Assembly
University of Virginia
  > WCFTO Home > Nano Home > Resources: The Need for Self-Assembly
 
       
 

PowerPoint Lecture Notes: The Need for Self-Assembly

University of Wisconsin MRSEC Movies on Self-Assembly:

Movies on self-assembly from the "Interdisciplinary Education Group" of the NSF Materials Research Science and Engineering Center (MRSEC). Web source:http://www.mrsec.wisc.edu/Edetc/cineplex/self/text.html

"Self-assembly of 5 micrometer glass nanospheres on a mica surface. The spheres are initially suspended in a drop of water on the mica. As the drop evaporates, the spheres are packed together by the surface tension at the drop's edge. Slight irregularities in the packing can be seen, and are the result of irregularly shaped spheres. (300K) Movie by Gordon Shaw."

"Triangles, made of polydimethylsiloxane with magnetized strontium ferrite along the edges, self assemble on the surface of water. The different color triangles are oppositely magnetized so they are expected to have the strongest attractions. The dish and camera are moved circularly to produce a wave that moves the pieces. The movie plays in real time." Movie by G.C. Lisensky

Note: This is only the first 60 seconds of the original eight minute movie.


Virtual Lab: Atomic Crystal Growth using Molecular Beam Epitaxy:

Ultra-high vacuum Molecular Beam Epitaxy (MBE) growth of GeSi atomic layers

Source: Virtual Lab http://WeCanFigureThisOut.org/VL/MBE.htm


Virtual Lab Simulations of "Quantum Cellular Automata" Electronic Device Building Blocks:

Square array of Q-dots with affinity for electrons. The dots are so small & close (~30 nm) that charges repel one another. Net result is that cell charges up with only two electrons that run to opposite corners of the cell.
The result it two alternate charging patterns => Digital 1 and 0!

Which can be manipulated by input signals on a pair of wires.
Further, the charge arrangement of the first cell will then propagate along a “wire” of such QCA elements!

Source: Virtual Lab http://WeCanFigureThisOut.org/VL/QCA_cells.htm


How Natural Atomic Self-Assembly Could form Quantum Cellular Automata Structures:

STEP 1) Strained Layer Epitaxy:

Compression of bonds between larger Ge atoms so that Ge layer will fit on more tightly packed Si substrate.

STEP 2) Spontaneous formation of atomic scale valley.

Compressed Ge atoms to side then relax into this valley.

STEP 3) Expanded Ge around valley then closer to natural spacing's of Ge atoms. It thus attracts subsequently deposited Ge atoms growing “Quantum Fortress” walls.

Under the proper choice of growth conditions, quantum forces are indeed observed for GeSi growth, as shown by the atomic force micrographs shown in the lecture notes for this class.

Source of animations: John C. Bean, WeCanFigureThisOut.org

 

Self-Assembly of Gold Nano Particles:

CytImmune's solution growth of gold nanoparticles for possible targeted delivery of cancer treatment drugs.

CytImmune Inc. "technology" webpage containing the above animation (click here)


Scripps Model of Virus Shell Self-Assembly:

Web source: http://mgl.scripps.edu/projects/tangible_models/movies

 

"Autocell Project" YouTube Web Videos - Apparently of the Same Viral Self-Assembly Process:

 

Autocell 1 - Correspondence between molecular structure and representation in animation.

 

Autocell 2 - How "V" shaped fragments guide assembly of triangular tiles. Then how tile surface guide assembly of more "V" fragments!

 
Autocell 3 - Another view of the two component self-assembly steps.
 
Autocell 4 - Completing the process as multiple tiles assemble into the viral shell.