Lab Information Prepare photoresist – groups of 3 to 4 people 1 mg oil red (solvent red 27) 3.5 g isobornyl acrylate (IBA) 2.0 g 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA) 0.18 g 2,2-dimethoxy-2-phenyl-acetophenone (DMPA) Wear gloves! Expose photoresist with UV lamp (goggles will absorb UV)

Special Nanomaterials & Carbon Nanotechnology (Section 4.4.6) Introduction to Nanotechnology

What are “special nanomaterials”? Materials that are made using unique processes Materials that have unique structures and/or properties Examples:

Special Nanomaterials: Outline Micro and Mesoporous Materials Ex. Zeolites, Metal-Organic Framework (MOF) Core-Shell Structures Carbon Nanotechnology Nanotubes Fullerenes Other organic molecules

Micro and Mesoporous Materials http://greman.univ-tours.fr/axis-3/porous-silicon-for-dummies-page-1-276071.kjsp

Random Mesoporous Structures Variety of methods of synthesis Oxidation of metal foils using acids Radiation-track etching Sol-gel processing aerogel: 75-90% porosity xerogel: ~ 50 % porosity

Sol Gel Processing http://www-cmls.llnl.gov/?url=science_and_technology-chemistry-solgel_chemistry

Crystalline Mesoporous Structures: Zeolites Crystalline aluminosilicates First discovered in 1756 34 are naturally-occurring 3-D framework with uniformly-sized pores Pores: ~ 0.3 – 1.0 nm in diameter Pore volumes: ~ 0.1 – 0.35 ml/g Applications: Catalysts Adsorbents/molecular sieves

Crystalline Mesoporous Structures: Zeolites N&N Fig. 6.13 N&N Fig. 6.12 Various arrangements Rings Cages Channels Chains http://omnibus.uni-freiburg.de/~weisenbt/7Zeolites/ZeoliteDefinition.html

MOFs Similar to zeolites, more syntheic flexibility

Core-Shell Structures Core and shell made of two different materials Differences: Crystal structure (lattices, arrangements of atoms) Physical properties Example: one metallic, one insulating Method of synthesis

Core-Shell Structure Example: Metal-Polymer Membrane-Based Synthesis Metal particles trapped inside pores Add polymer solution into pores and react Use as ligand and polyimerize Fratoddi et al. Nanoscale Research Letters 2011, 6:98

Membrane Based Core-Shell Nano Lett. Sep 2006; 6(9): 2166–2171. Au shell, polyaniline core

Other Core-Shell Semiconductor Passivation More Tunability Chemistry of Materials 2011, 23, 4587–4598. Semiconductor Passivation More Tunability

Carbon Nanostructures Variety of properties Metallic conductor (graphite) Semiconductor (diamond) Insulating Polymer (hydrocarbon chains) 3-D 2-D Variety of structures 1-D 0-D

Carbon Fullerenes 0-dimensional carbon structure Usually C60, but also refers to C70, C76, Cn (n > 60) Every carbon site on C60 is equivalent Bonded to three other carbons average bond is 1.44 Å (C-C is 1.46 Å; C=C is 1.40 Å) 20 hexagonal faces; 12 pentagonal faces Diameter: 7.10 Å

Buckminster Fuller (1895-1983): Architect, engineer, inventor; Developed the geodesic dome

Synthesis of Fullerenes Laser ablation (vaporizing graphite with a laser) Plasma arcing of graphite or coal Fullerenes found in the soot Combustion synthesis Burn hydrocarbon at low pressure http://cnx.org/contents/4a177b0e-1228-41d4-9d62-d4f0a9a3f335@1/Buckyballs:_Their_history_and_

Carbon Nanotubes Single-Walled Carbon Nanotubes (SWCNT; SWNT) Multi-Walled Carbon Nanotubes (MWCNT; MWNT) Preparation: Arc evaporation (plasma arcing) Laser ablation PECVD Electrochemical methods Addition of transition metal powder encourages SWNT growth

Carbon Nanotubes Armchair (b) Zigzag (c) Chiral

Flavors of nanotubes Armchair is metallic Zigzag/Chiral are semiconducting (small bandgap) Most methods produce mixture Catalysts, sorting techniques to separate Nature 512, 61–64 (07 August 2014)

Properties of Carbon Nanotubes Mechanical Stiff and robust structures C-C bonds in graphite (and nanotubes) is the one of the strongest bonds in nature Flexible; do not break when bent Conductivity Extremely high thermal conductivity Extremely high electrical conductivity Potential Applications: catalysis - hydrogen storage - biological cell electrodes resistors - flow sensors - electron field emission tips electronic/mechanical devices - scanning probe tips http://www.rps.psu.edu/hydrogen/form.html

Carbon Nanotube Applications (NEMS) “Nantero is a nanotechnology company using carbon nanotubes for the development of next-generation semiconductor devices... In the field of memory, Nantero is developing NRAM™, a high-density nonvolatile Random Access Memory.” Cedric – computer made with SWNT -align nanotubes -obtain only semiconducting morphologies - 8 micron features http://www.bbc.com/news/science-environment-24232896 http://www.nantero.com/

Carbon Nanotube Applications Gold plate ~ (100 nm)2 attached to outer shell of suspended MWCNT (on Si wafer) “electrostatically rotate the outer shell relative to the inner core” http://en.wikipedia.org/wiki/Nanomotor

Carbon Nanotube Applications Nanotechnology 22 (2011) 435704 Aligned sheet of MWNT, Thermally activated

Other Organic Molecules acetone Small molecules solvents metabolites reactants or monomers Large molecules; “macromolecules” biomolecules e.g. DNA, proteins, lipids carbon nanotubes polymers

Organic Nanotechnology http://www.nanowerk.com/spotlight/spotid=4343.php http://www.kurzweilai.net/butterfly-molecule-could-lead-to-new-sensors-photoenergy-conversion-devices