Nanomaterials: Why Size Matters. Current & Potential Impact of Nanotechnology Nano is Everywhere

Transcription

1 Nanomaterials: Why Size Matters. Current & Potential Impact of Nanotechnology Nano is Everywhere April 17, 2010 INNOVATION Teaching Nanotechnology within Virginia SOLs Center for Diversity in Engineering, University of Virginia Lisa E. Friedersdorf, PhD Managing Director, nanostar Institute, UVa President, AdviSci

2 Materials in General Lets start with bulk materials. What are typical material classifications? What are the basic properties? (mechanical, thermal, electrical, etc.)

3 T m - Melting Temperature phase transformation from solid (tightly bound) to liquid (loosely bound) E - Stiffness resistance to elastic deformation (non- permanent) α - Thermal Expansion Coefficient fractional change in length with one degree change in T Why? Let s compare the following properties for metals, ceramics, and polymers.

4 What s the BIG deal about something so SMALL? Materials behave differently at this size scale. Unique and interesting properties for example Gold, Silver, Allotropes of Carbon Color depends on particle size Core & Core-Shell Quantum Dots, Evident Technologies Applications are endless!

5 Size Matters As the particle size gets smaller, a higher fraction of the atoms are at the surface.

6 Electrical properties as an example Callister, Wiley

7 Callister, Wiley Metals Insulators and semiconductors

8 Quantum Dots Too small to consider continuous bands in electronic structure. Floro, MSE Phillips Research

9 It s not just size, arrangement matters, too. For example, allotropes of Carbon Buckyballs Diamonds Graphite

10 Carbonaceous Nanomaterials Petra Reinke, UVA Carbon Onions, clusters Harry Dorn - VT Buckyballs (fullerenes) Nanotubes Nanosheets Nano-onions NanoSheets (APL 2004) Brian Holloway - CWM Smalley, et al Nature 1985 Bethune, Dorn, Stevenson Nature 1994; Stevenson, Balch, Bible, Dorn, et al. Nature 1999 Iijima, et al. Nature 1993, Bethune, et al. Nature 1993 MWNT, Albin, ODU

11 Carbonaceous nanomaterials are exciting because of their amazing material properties. Nanotubes, for example: Mechanical 100 times stronger than steel Electrical Conduct electricity better than copper Depending on flavor metal or semiconductor Thermal Conduct heat better than diamonds Optical/ Surface/ Geometry, etc. properties also being exploited NASA

12 So now, at the nanoscale, we have to rethink how materials behave. It is an exciting time for a scientist

13 Nanoelectronics Then: Gigantic Computers Now: Handheld Devices yorkblog.com cybernetnews.com The very first computers were highly inefficient and took up incredible amounts of space. This computer, ENIAC, was built in Computers can now fit in your hand. Many handheld devices have more computing power than the computer to the left.

14 Impact of Nanoscience on Medicine Pangaea Clinic of Naturopathic Medicine Chemotherapy, a leading treatment in the past, while effective in killing cancerous cells also kills healthy cells. ACS Publications, Nano Letters Loading gold nanoparticles with cancer killing drugs allows for targeting of malignant cells exclusively.

15 Spano, Biology TEM Image of Uranyl Acetate-Stained Encapsidated 5 nm Gold Nanoparticles in GTA Proheads (80,000X) Medicine empty Kelly, BME singly filled doubly filled Sheng, Radiation Oncology Landers, Chemistry Botchwey, BME Gillies, MAE

16 McIntosh, ChE Alternative Energy Heflin, VT Fuel Cells McGrath, VT Solar Cells Organic Solar Cells Loth, MAE Laser-textured Silicon for Solar Cells UBC Gupta, ECE

17 Thank you. Questions?