The Fusion of Biology and Materials Science through Hands-On Activities and

Demonstrations

Daniela M. Topasna Gregory A. Topasna

Virginia Military Institute National Educator Workshop

March 2010

I. Measuring

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Scale

•  http://www.aspshop.net/upload/upimg2/Jump-Rope-36682.jpg •  http://www.alliedkenco.com/catalog/images/WIRE_VACUUM_SEAL.jpg •  http://www.answersingenesis.org/assets/images/articles/am/v2/n3/

Human_Hair3.jpg •  http://en.wikipedia.org/wiki/File:Kohlenstoffnanoroehre_Animation.gif

Human hair

1 cm = 10mm 1mm 100 µm (1/10 mm)

1 nm

Rope Wire Human Hair Carbon nanotube

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~0.1nm

~1 m

~5 mm

~ 5 µm

~3 cm

~100 µm

~ 1nm

~ 8 µm

A Sense of Scale

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Measuring

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Measuring

? or

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Measuring Scaling

Fractions Grasping smaller dimensions

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II. Images

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Activity: Comparison of images at macro- and nanoscale

•  The next exercise is intended to emphasize the presence and importance of topography and structure at the nanoscale by comparing similar images at the macro- and nanoscale. The image pairs aim to demonstrate that it is the combination of chemical composition, shapes, and topography that affect the properties of these materials. In addition, the images will stress the importance of placing the scale bars. Students will see similar images (with or without explanation). They are asked if they can guess what the images represent, which ones are macro/nanoscale, and to compare the scales. Discuss the material(s) used, applications, and structure. One could also discuss how nanoscale image was taken: SEM, AFM, importance of such instruments. The emphasis is of course on the nanoscale images. Explanation for some of the images might be for an advanced high school or undergraduate level, however the images are unique, intriguing, and interesting to show to elementary and middle school students as well. 9

Materials imaging and length scales

Galaxy Dirty microscope slide

Core of Andromeda galaxy – 2.2 million light years away

Microscope slide with dust particles (mm to µm)

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http://remf.dartmouth.edu/images/botanicalPollenSEM/source/12.html http://patdollard.com/wp-content/uploads/puffer-fish-puffed.jpg

Pollen from a variety of common plants: sunflower [Helianthus annuus], morning glory [Ipomea purpurea], hollyhock [Sildalcea malviflora], lily [Lilium auratum], primrose [Oenothera fruticosa] and caster bean [Ricinus communis].

Puffer Fish – up 50 cm (20 in) long Pollen 3-200 µm in diameter

Spikes are used for defense

Spikes are used for attachment to spread seeds.

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Sand Dunes in Death Valley Photo by Jack Starr The size of these structures varies from a few cm to hundreds of meters.

Copper (111) surface by Eigler et al. NATURE 363, 1993 Important in materials studies – surface state electrons. The standing waves are about 15 Angstroms (roughly 10 atomic diameters) from crest to crest. The amplitude is largest adjacent to the step edge where it is about 0.04 Angstroms from crest to trough.

Sand dunes Copper surface

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STM image Fe (48 atoms) on Cu Surface states electrons are seen which demonstrates the wave property of matter Don Eigler, IBM

http://commons.wikimedia.org/wiki/File:Corral_of_Wagons_BHoU-p255.png

Quantum corral Corral = enclosure

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Cabbage Coral (Turbinaria reniformis) reef, also known as Scroll Coral found in the Great Barrier Reef, Queensland, Australia. Can grow several inches to feet

http://gift.kisti.re.kr/techtrend/uploadfile/upload/ch_ahn/nanoflowers.jpg

Crystal engineering designs and fabricates specific nanoparticles for nanoelectronic devices, filtration, etc. This MoS2 nanoflower is created by heating MoO2 film in a sulphur atmosphere.

Cabbage coral Nanoparticles (nanoflower)

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Jacks Design of hybrid sol–gel films for direct x-ray and electron beam nanopatterning G Brusatin, G D Giustina, F Romanato and M Guglielmi

www.iop.org/journals/nano

http://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/Jacks.jpg/800px-Jacks.jpg

Size – few cm Used for fun

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Divinity – well, just divine desserts ☺

Pentacene film (400 nm) grown from hyperthermal molecular beams used for organic thin films transistor (OTFT) displays Pentacene consists of five linearly fused benzene rings C22H14

Pentacene film "terrain" viewed by atomic-force microscope (AFM). http://news.chess.cornell.edu/articles/2007/MRSposterAward.html http://www.ehow.com/how_5651384_make-oh-good-divinity-

fudge.html

Several cm in size (and tasty)

Pentacene film

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Death Valley – dried mud AFM image of a physical vapor deposition (PVD) gold film, 50 nm “thick

http://www.bam.de/en/kompetenzen/fachabteilungen/abteilung_6/fg64/fg64_ag1.htm

http://www.wildnatureimages.com/dried_mud_photos.htm PVD is a thin film deposition method in vacuum by the condensation of a vaporized form of the material onto the surface. Studies of these films help to improve the deposition method. The films are used for various electronic devices and sensors.

Features are ~ cm

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III. Biomimetics

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Activity – introduce biomimetics through several examples

•  Biomimetics = the development of a novel material or product based on an idea, principle or mechanism borrowed from nature. (P. Holister et al., “Nanoparticles”, Cientifica, nr. 3, 2003)

•  Next slides show several images of mechanisms that work in nature and how humans are using them in everyday applications –  Lotus surface – superhydrophobic surface due to micro- and

nanoscopic “spikes” on the surface – repels dirt and water. Similarly, specially made hydrophobic coatings (paints, fabrics) on glass or metals allow for self-cleaning properties, reduce buildup of ice and snow.

•  Continually new products, ideas are researched and implemented. 19

Lotus (Nelumbo lucifera) and superhydrophobic surfaces

Lotus leaf (bumps and wax)

Self cleaning surfaces – lotus effect (applied on steel, silicon, glass surfaces)

http://wthielicke.gmxhome.de/bionik/indexuk.htm

http://www.teasnursery.com/PhotoContest/LotusLeafandPetals_JerryPan.jpg

http://www.physorg.com/news88088727.html

http://ssp06.isunet.edu/the_lotus_effect.htm

Published in: L. Zhai; F.Ç. Cebeci; R.E. Cohen; M.. Rubner; Nano Lett. 2004, 4, 1349-1353. DOI: 10.1021/nl049463j; Copyright © 2004 American Chemical Society 20

Burdock and Velcro (hook and loop fastener)

•  Burdock – plants with prickly thorns that can catch fur and clothing

•  Velcro – “velours” and “crochet” •  Invented in 1941 by Georges de Mestral –

Switzerland

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Velcro

http://www.flickr.com/photos/olivepixel/220573423/

Burdock – Arctium tomentosum (photo by Epukas)

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Sea shell (nacre – mother of pearl) and hard coatings

a, The natural strength, hardness and toughness of bone and shell are attributable to their nanoscale structure of calcium carbonate bricks and mortar-like protein layers. By mimicking this structure, Tang et al.1 have created a new material with mechanical properties similar to nacre, or mother-of-pearl. b, Montmorillonite bricks (0.9 nm thick) are deposited layer by layer above a silicon-wafer substrate, alternating with polymer chains of mortar. c, Structures that are many layers deep can be built — this one has 100 brick and polymer layers — although the process is slow.

Tang et al. , NATURE|VOL 423 | 26 JUNE 2003 |www.nature.com/nature 23

Nature made photonic crystals •  Occur in nature – opal (from Greek "Opallos" meaning to "see a change

(of color)“, beetle wings, butterfly wings (see Morpho butterfly) •  Opals: hydrated silica (3% up to 20% water) spheres - 150 to 300 nm in

hexagonal or cubic closed packed lattice •  Beetle – diamond like structure of the scales in the wings •  Butterfly – discrete multilayer cuticles and air. Scales are ~ 120 µm

http://www.photomacrography1.net/forum/viewtopic.php?t=2341

Brazilian beetle – iridescent green is given by the diamond like structure of the scale

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Fabricated photonic structures PBG “wood pile” structure fabricated by photolithography and etching

- Mono-disperse silica spheres (<5% variation in diameter)

- Diameter range 0.4 - 1.0 microns

- Self assembled into fcc lattice

Sajeev John, U Toronto

Self-assembled photonic structures

S.Y. Lin et al., Nature 394, 251 (1998) 25

Carbon forms Graphite = stacked hexagonal sheets of sp2 hybridized with π bonding orbitals

C-C-C bond angles 120º Electrical conductivity

Diamond = interlocking sp3 hybridized C atoms bonded to four other C atoms

tetrahedral 3D lattice C-C-C bond angles 109.5º Hardness

Fullerenes – third allotropic form of carbon-sp2 – 1985

carbon chemistry in Red Giant Stars

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C60 - Properties •  20 hexagons and 12 pentagons (IPR) •  Inert •  Nontoxic •  0.7 nm (~one millionth diameter of human

hair) •  Strong localized π electron system •  They spin at over one hundred million times

per second •  can withstand slamming into a stainless steel

plate at 15,000 mph, merely bouncing back unharmed.

•  Solvents: CS2, o – dichlorobenzene, toluene, xylene

•  Readily vaporizes in vacuum around 400 ºC •  Low thermal conductivity •  All 60 C atoms are chemically equivalent

C70 = 2 x C60 caps with an extra row of hexagons in between ( 25 hexagons and 12 pentagons)

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