3.052 Nanomechanics of Materials and Biomaterials

Prof. Christine OrtizDMSE, RM 13-4022

Phone : (617) 452-3084Email : cortiz@mit.edu

WWW : http://web.mit.edu/cortiz/www

LECTURE # 1 : INTRODUCTION TO NANOMECHANICS

Basics of Nanotechnology

Readings :1. "There's Plenty of Room at the Bottom," Richard P. Feynman's Classic Nanotechnology Talk (1959,

APS-Caltech); 2. “Engines of Creation : The Coming Era of Nanotechnology,” K. Eric. Drexler, Anchor Books,

Doubleday, 1986 (Chapter 1)

Specific Definition :“Molecular Manufacturing”

Broad Definition :

Electron-microscope image of the world's smallest guitar, based roughly on the design for the Fender Stratocaster, a popular electric guitar. Its length is 10 millionths of a meter-- approximately the size of a red blood cell and about 1/20th the width of a single human hair. Its strings have a width of about 50 billionths of a meter (the size of approximately 100 atoms). Plucking the tiny strings would produce a high-pitched sound at the inaudible frequency of approximately 10 megahertz. Made by Cornell researchers with a single silicon crystal, this tiny guitar is a playful example of nanotechnology, in which scientists are building machines and structures on the scale of billionths of a meter to perform useful technological functions and study processes at the submicroscopic level. (http://www.news.cornell.edu/science/July97/guitar.ltb.html, Dustin W. Carr and

Harold G. Craighead, Cornell.)

“Nanostructure”

Nanostructured Materials(*http://www.rpi.edu/dept/materials/COURSES/NANO/crawford/index.html)

Bone

Self-Assembling MonolayerNanoporous Alumina

Membrane

Nanostructured Materials

“Bottom-Up Manufacturing”

“Top-Down Manufacturing”

What is Nanomechanics ?

Summary of Length Scales (m)

Biological Sciences

Materials Sciences

10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2 100 102 104 106 1025

atomic radiicovalent bond

0.1 nm

width of DNA,small globular

proteins 2 nm

hemoglobin 6.6 nm

bacteria,internal

organelles 1 m

cell 50 m

height of a human being

1m

length of a blue whale

height of Mt. Everest 8848 m

diameter of theearthsize of

of a bee

atomicnucleus

proton,neutron

virus

radius of AFM probe tip

size of C60 molecule,diameter of

carbon nanotube,suprmolecular chemistry,

colloidal particles,nanolithography

microelectromechanical

systems(MEMS),

micro-contact printing,

integratedcircuit

transistor

length of a Boeing 767

airplane

height of NYC

World Trade Center

quark

traditionalman-made

materials andstructures

lengthof the

Great Wallof China

size of the universe

10-18

electron

crystal grains

smallest observable feature

of human eye,thickness ofhuman hair

integratedcircuit

chip

grain ofsand

WHY STUDY NANOMECHANICS ?

THREE EXAMPLES FROM BIOLOGY

Inflammatory Response :Cell Rolling and Adhesion

Muscle Elasticity

(*MARSZALEK, et. al Nature 402, 100 - 103 (1999))

(*Cell and Molecular Biology, G. Karp)

SARCOMERE

TITINActin TITINMyosinNebulin

Packing the Genome

DNAsimulation(*FEBS Lett. 371:279-282)

Packing the Genome

http://gened.emc.maricopa.edu/Bio/BIO181/BIOBK/BioBookCELL2.html

WHY STUDY NANOMECHANICS ?

THREE EXAMPLES FROM MATERIALS SCIENCE

Performance of Computer Hard Diskshttp://talke08.ucsd.edu/index/disk.html

Computer Head-Disk Interface

2 mm

sliderhead flexure

suspension arm

flying height 30-60 nmread / write element

hard disk

recording head

surface roughness 30-60 nm

http://talke08.ucsd.edu/index/disk.html

Properties of Colloids

Silica sphere glued to an AFM-probe tip

(*http://wintermute.chemie.uni-mainz.de/coll.html)

Macroscopic Mechanical Properties of Materials

Non-Linear, Entropic Elasticity of Polymer Networks

Rubber Elasticity

FrFchain

Fchain

F

F

F

More Disorder Less Disorder

Entropy - a natural law that expresses the driving force towards disorderrandom coil

A Typical High-Resolution Force Spectroscopy

Technique : General Components

sensor output

sample

high-resolutionforce

transducer

displacement detection

system

high-resolution

displacement control

computer• controls system

• performs data acquisition, display, and analysis

z

probe