Forskjell mellom versjoner av «TMT4320 - Nanomaterialer»

Revisjonen fra 11. des. 2008 kl. 21:46

Kort om faget

Emnet skal gi en innføring i grunnleggende kjemisk prinsipper for å lage nanomaterialer.

Stikkord: "Self-assembled" monolag (SAM) og hvordan disse kan formes ved myk litografi og "dip pen" nanolitografi, syntese av tredimensjonale multilag strukturer. Tynne filmer ved kjemisk gassfase deponering. Syntese av nanopartikler, nanostaver, nanorør og nanoledninger. Våtkjemiske syntese av oksidbaserte nanomaterialer. "Self-asembly" av kolloidale mikrokuler til fotoniske krystaller, porøse nanomaterialer, blokk-kopolymere som nanomaterialer. "Self assembly" av store byggeblokker til funksjonelle anordninger.

Et lite kompendium i faget

Her vil det etterhvert vokse fram et lite kompendium i faget. Dette følger i utgangspunktet pensumlista som gjelder for høsten 2008.

Kapittel 2: Soft Lithography

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Kapittel 3: Building layer-by-layer

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Kapittel 4: Nanocontact printing and writing

• Soft lithography and microcontact printing (sections 4.1-4.3 + lecture notes)
  • Explain basic principles and explain advantages and limitations.
  • Explain how a patterns printed with a PDMS stamp can be made smaller by manipulating the stamp or using other tricks.
  • Explain how the properties of the ink and the contact time (reactive spreading) can influence the size of the patterns.
• Dip pen nanolithography
  • Be able to explain basic principles and give a couple of examples of what it can be used for (no need to know exact details of each example). Examples that are good to know are that you can write for example solutions that can be transformed into metals or metal oxides by post-treatments such as temperature.
  • Sol-gel DPN (section 4.10)
  • Enzyme DPN (section 4.15)
  • Electrostatic DPN (section 4.16)
  • Electrochemical DPN (section 4.17)
• Whittling of nanostructures (section 4.18)
  • Only be able to explain basic principle
• Nanoplotters and nanoblotters
  • What are these and what can they be used for?
  • Be able to explain basic principles.
• Combinatorial libraries
  • Be able to explain the basic principle and how it is used to find new and improved materials.

Kapittel 5: Nano-rod, nanotube, nanowire self-assembly

• Templates for synthesis of nanorods
  • How to make Si and Al2O3 templates
    • Straight pores vs modulated diameter pores.
  • Need to know basic principles behind both synthesis methods. Which parameters determine diameter, ordering, length etc?

• How are these templates used to make nanorods and nanotubes
  • Complete filling gives nanorods – electrodepositionI (also called electroplating) and electroless depositionII. Be able to explain the synthesis route for these two methods.
  • Partial filling gives nanotubes – spontaneous wetting using sol-gel or grow layer-by-layer using CVD or ALD.
  • Modulated composition nanorods.
• Magnetic nanorods (sections 5.7 and 5.8)
  • Explain how they assemble based on the geometry of the magnetic segment.
  • Explain how magnetic nanorods can be used to separate specific molecules from a solution.
• Be able to explain how you can make nanorods with both axial and radial composition profiles. Which methods can be used? Also be able to explain how nanorods with a radial composition profile can be used to make nanotubes.
• Single crystal nanowires
  • Synthesis methods
    • VLS synthesis (section 5.15)
    • SFLS synthesis (section 5.17)
    • Pulsed laser deposition
  • How can you make them branch out?
  • Nanowire quantum size effects (section 5.18)
  • Alignment methods
    • Electric field based alignment
    • Microfluidic approach
    • Langmuir-Blodgett
  • How can you get the nanowires to grow in ordered arrays either parallel or perpendicular to the substrate? (Identical to methods used for carbon nanotubes)
  • Application areas
    • LED – be able to explain briefly how to make a nanowire LED and what the important factors are to make a good quality device.
    • Transistors – be able to explain briefly how you can make a simple transistor and how it can be used as a sensor by exploiting adsorption dependent conductivity.
    • Nanowire UV photodetector (section 5.35)
• Simplifying complex nanowires (section 5.36 and lecture notes)
  • Template method
  • Hydrothermal synthesis
• Electrospinning (sections 5.39, 5.40 and lecture notes)
• Carbon nanotubes (sections 5.41, 5.42, 5.44, 5.45-5.48 and lecture notes)
  • What are carbon nanotubes? Be able to describe the three different structures they can have and how their properties are different.
  • Be able to describe briefly (basic principles) at least two of the three main methods used to synthesize carbon nanotubes
    • Arc discharge
    • Laser ablation
    • CVD
  • How can the different structure nanotubes be separated from each other and from other carbon particles.
  • Be able to say something about their properties
    • Mechanical
    • Electrical
    • Chemical
  • Know some about carbon nanotube chemistry (reactivity on the surface vs the ends etc.)
  • Aligning of carbon nanotubes
    • Evaporation induced self-assembly
    • Patterned hydrophilic SAM on substrate – carbon nanotubes will assemble only on the hydrophilic patches.
    • Alignment by pre-existing patterns
      • Perpendicular to substrate
      • Parallel to substrate
    • AC/DC electric fields
  • Applications of carbon nanotubes
    • Sensors
    • Strengthening of materials (composites)
    • Added to materials to improve conductivity

Kapittel 6: Nanocluster Self-Assembly

• What is a capped nanocluster? What does it mean that it is capped?
• Be able to explain general principles for synthesis of capped nanoclusters (arrested nucleation and growth). How would you explain the synthesis from the nucleation process to the final capped nanocluster? What type of chemicals (i.e. capping agents, surfactants and precursors) are needed? Do not need to know specific names of chemicals, only whether it’s a capping agent, a surfactant, complexing agent etc. and what the purpose of these different chemicals are.
• How can you minimize size dispersity by confining the reaction space? (section 6.6)
• Be able to explain how you can tune properties through physical dimensions rather than chemical composition (quantum size effects).
• Be able to explain briefly how different phases can occur for smaller size particles, similar to temperature and pressure dependent phase transformations in bulk materials. (section 6.8)
• Need to know how to make nanoclusters water soluble. (section 6.13)
• How can nanoclusters be separated by size using a non-solvent and centrifugation?
• What is a superlattice, how can it be assembled and why do we want to make superlattices? (change of properties, properties of superlattice does not necessarily equal the sum of the properties of the individual constituents)
  • Assembly techniques include tri-layer solvent diffusion crystallization, sedimentation, evaporation induced self-assembly, and Langmuir-Blodgett technique.
  • How can capping agents (different type and length) affect the properties of a superstructure? (section 6.15)
  • Alloying core-shell nanoclusters
• Nanocluster-polymer composites
  • What is it?
  • How can it be used for down-conversion of light?
• Be able to give one or two examples of how different size nanoclusters labeled with different fluorescent molecules can be used in biology.
• What is a tetrapod and what is the main priciples of the synthesis behind the tetrapod?
  • Using a material that has two common crystal polymorphs where growth of one over the other can be controlled by synthesis temperature.
  • Use of a long chain molecule which selectively binds to specific facets of the structure and hinders growth in those directions. This confines the growth of the material to one spatial dimension.
• Photochromic metal nanoclusters (section 6.31)
  • Be able to explain what happens to silver nanoclusters embedded in a titania matrix when it is exposed to either UV-light or visible light.
• What is a buckyball and what can it be used for? What special properties does it exhibit? (Do not need to know specific details of synthesis or assembly techniques.)

Kapittel 7: Microspheres – Colors from the Beaker

• What is a photonic crystal (combination of high dielectric contrast and periodicity at the light scale)
  • 1 dimensional
  • 2 dimensional
  • 3 dimensional
• Be able to explain how photonic crystals can be used to confine and guide light by the controlled synthesis of different defects
  • Point defects
  • Line defects
  • Plane defects
• Be able to explain at least two different methods used to induce defects in a material
  • Writing defects
  • Synthesizing planar defects by introducing a dense layer or a layer with spheres of a different size than the surrounding colloidal crystal.
• Be able to explain how you can tune the color by changing size of the structure and changing dielectric contrast. What happens if the spheres are embedded in a shrinkable and swellable matrix? How can this be used as a sensor to detect different cations?
• What are core-corona, core-shell-corona and multi-shell microspheres, how can you make them and what is the purpose of making these spheres?
• Know the differences between one-stage and re-growth synthesis.
• Know what the basic principles of self assembly are. Be able to name and explain the following self-assembly techniques for microspheres
  • Sedimentation (be able to explain in more detail)
  • Electrophoresis
  • Hydrodynamic shear
  • Spin coating
  • Langmuir-Blodgett layer-by-layer (be able to explain in more detail)
  • Parallel plate confinement
  • Evaporation induced self-assembly (be able to explain in more detail)
• What are colloidal aggregates? Need to be able to explain different techniques for manufacturing different shapes of these, such as template confinement, aggregation in homogeneous emulsion, and electrospraying.
• Need to know that the basic principle behind optical quality of colloidal crystals is based both on Bragg’s law of diffraction and Snell’s law of reflection. Need to be able to understand and explain how the color of the diffracted light changes with the distance between lattice plains.
• Cracking: Why do colloidal crystal films crack and what can you do to prevent it? Need to be able to explain briefly one or two methods of how you can stabilize a colloidal crystal lattice without causing cracking.
• What is a liquid crystal photonic crystal? How can the colors of such a crystal be altered and what can it be used for?

Reactions that you need to know:

• Reaction of alkane thiolate with gold. Important to know that alkane thiols have a specific affinity for gold (also keep in mind that silver and gold have very similar properties).
• Reaction that occurs when during anodic oxidation of Al to produce porous alumina membranes.
• Reaction that occurs when silica microspheres are formed from Si(OEt)4 and water (section 7.9).

Eksterne linker

• NTNUs fagbeskrivelse
• Timeplan Høst08