3.052 Brief Summary of Lectures :
IMPORTANT NOTE :
Please come to lecture on time!
The most important part of the lectures is given in the first 15 minutes!
I will start lecture at exactly 5 minutes past the hour.


· Introduction to Nanomechanics (CO1)
· MOVIE: Richard P. Feynman's Lecture on Nanotechnology (1984) : "Tiny Machines"(1)
· Experimental Aspects of Nanoindentation (KVV2)

· Experimental Aspects of High Resolution Force Spectroscopy (CO3)
· High Resolution Imaging with Forces : The Atomic Force Microscope (KVV1)

· Qualitative Introduction to Intra- and Intermolecular Forces (KVV1)
· Quantitative Description of Intra- and Intermolecular Forces (CO1)
· Interparticle and Intersurface Forces (CO2)
EXAM #1
· Chemical Force Microscopy (CO1)

· Electrostatic Interactions Between Charged Surfaces in Liquids (CO1)
· Nanomechanics of Tissues, e.g. Cartilage (CO1)

· High-Resolution Force Spectroscopy of Cells (CO1)

· Contact Mechanics and Nanoindentation (KVV2)

· Theory of Elasticity of Single Macromolecular Chains (CO2)
· Nanomechanics of Synthetic and Biological Polymers (CO2)
EXAM #2

· POWERPOINT FILES OF LECTURE NOTES HERE

 

DETAILED SUMMARY OF LECTURES :

Material Covered

Additional Readings

1. Introduction to Nanomechanics (CO) :
· what is nanomechanics?
· historical background
· summary of length scales compared for biology and materials science
· nanotechnology
· four fundamental forces of nature
· summary of force scales compared for biology and materials science
· why is nanomechanics important to study? (*movies)

· Israelachvili, pgs. 3-15, 27-29
· Feynman's Classic Nanotechnology Talk (1959, APS-Caltech); "There's Plenty of Room at the Bottom"
· "Engines of Creation : The Coming Era of Nanotechnology," Chapter 1, K. Eric Drexler, Doubleday, 1986.
· "Nanotechnology : Shaping the World Atom by Atom," US National Science and Technology Council, 2000

Richard P. Feynman's Lecture on Nanotechnology (1984) :

"Tiny Machines"

· Short biography of Richard P. Feynman (1)
· Short biography of Richard P. Feynman (2)
· Feynman Links / Feynman's books at Amazon.com

2. Experimental Aspects of Nanoindentation : I (KVV)
 · definition / motivation / applications
· materials engineering
· mechanics of small volumes
· materials physics

· load versus indentation depth, indentor considerations

· how does indentation work, capacitor, calibration, environmental control, positioning, transducer

· results in bulk materials and thin films, coatings, composites, alloys, copolymers

· none

3. Experimental Aspects of Nanoindentation : II (KVV)
· Results in thin films, effect of substrate

· polycrystal versus single crystal response

· elastic and plastic response

· discrete plasticity

· localized stress

· experimental bubble raft model

· none

4. Experimental Aspects of High- Resolution Force Spectroscopy : I (CO)
· introduction to high-resolution force spectroscopy
· description of general components and function of each component
· force transducers
· cantilever beam theory
· force sensitivity
· fundamental physical limits of force detection : harmonic oscillators

· Ortiz handouts : (1) review / summary of cantilever beam theory, (2) summary of harmonic motion, and (3) limits of force detection
· Handouts from "Vibrations and Waves,"A. P. French, W. W. Norton and Company, 1971

5. Experimental Aspects of High-Resolution Force Spectroscopy : II (CO)
· displacement detection : Optical Lever Deflection Technique
· displacement control : piezoelectrics
· optical and magnetic tweezers
· surface forces apparatus
· biomembrane surface probe

· comparison of force detection limits and force ranges

· Handouts from Physik Instrumente, Inc., "Basic Introduction to Nanopositioning with Piezoelectric Technology"

· Israelachvili, pgs. 168-174

6. Experimental Aspects of High-Resolution Force Spectroscopy III : Force versus Distance Curves (CO)
· conversion of raw data to force versus separation distance
· regions of typical adhesive force versus distance curve; e.g. cantilever instabilities, constant compliance regime

· "Atomic Force Microscopy: Measuring Intermolecular Interaction Forces," National Research Laboratory.
· "Scanning Probe Microscopy : Technology Overview," Digital Instruments Application Note.
· "Basic Principles of Scanning Probe Microscopy," North Carolina State University (USA).
· "Introduction to Atomic Force Microscopy," University of Guelph (CA).

7. High-Resolution Imaging With Forces : The Atomic Force Microscope (AFM) (KVV)
· components of the AFM
· high resolution imaging using a feedback loop
· AFM modes of operation
· first reported atomic resolution images on hard, crystalline materials
· high-resolution imaging of biological samples; e.g. cells and biopolymers

· same as above

8. Qualitative Introduction to Intra- and Intermolecular Forces : (KVV)
· covalent
· metallic
· ionic (i.e. charge-charge)
· polar interactions (e.g. charge-dipole, dipole-dipole, hydrogen bonding)
· polarization interactions (e.g. charge-nonpolar, dipole-nonpolar)
· dispersion or london interactions (i.e. nonpolar-nonpolar)
· special interactions (e.g. hydrophobic, hydrophilic, entropic elasticity)

·`Handouts from Cell and Molecular Biology, G. Karp, 1991.
· Israelachvili, Sections 3.1, 3.2, 3.4, 4.1, 4.3, 4.7, 6.1, 6.2, 7.1, Chapter 8

9. Quantitative Description of Intra- and Intermolecular Forces : (CO)
· intra- and intermolecular potentials, forces, and stiffnesses : general mathematical form
· noncovalent van der Waals interactions-Lennard-Jones potential
· covalent interactions- Morse potential
· harmonic approximation
· thermal expansion
· comparison of potentials for different types of interactions
· comparison of binding energies for different types of interactions
· comparison of interaction distance ranges for different types of interactions

· same as above

10. Interparticle and and Intersurface Forces : (CO)
· bridging the gap between length scales
· derivation of interaction potential between a molecule and flat surface
· derivation of interaction potential between a sphere and flat surface
· derivation of interaction potential between two flat surfaces
· summary of dispersion van der Waals interaction potentials
· comparison with experimental data
· retardation effects in dispersion van der Waals interactions

· Israelachvili, Sections 6.9, 10.1-10.3, 11.1, 11.2

EXAM #1

11. Chemical Force Microscopy (CFM) : (CO)
· self-assembled monolayers with uncharged functional groups
· self-assembled monolayers with charged functional groups
· protein-SAM CFM

· TBA

12. Electrostatic Interactions Between Charged Surfaces in Liquids (CO)
· the electric double layer
· the interaction between charged surfaces in solution : the contact value theorum
· the interaction between charged surfaces in the presence of an electrolyte
· DLVO theory

· Israelachvili, Sections 12.1-8, 12.11, 12.15-18

13. Nanomechanics of Cartilage (CO)

· TBA

14. High Resolution Force Spectroscopy of Cells and Bond Strength Measurements : (CO)
· biomembrane surface probe
· introduction to biomolecular adhesion (ligand-receptor interactions) and relevance to cell adhesion
· reaction-rate theory, theory of molecular kinetics under force in liquids
· theory of force distributions in probe experiments
· energy landscapes :
· biotin-strept(avidin)
· carbohydrate-L-selectin
· anchoring strength of lipids in membranes
· serial linkages
· rupture of bonds connected to flexible polymer chains
· rupture of covalent bonds

· TBA

15. Contact Mechanics and Nanoindentation : I (KVV)
· review of force-displacment response for bulk solids
· geometry of contact hysteresis
· work of contact deformation
· contact mechanics : definition
· effect of relative stiffness on contact mechanics
·Hertzian elastic contact theory
· elastic nanoindentation

· Papers distributed in class

· ''Nanoindentation'', A.C. Fischer-Cripps, Springer 2002

16. Contact Mechanics and Nanoindentation : II (KVV)
elastic-to-plastic deformation
· load versus indentation curves of various materials :
· linear elastic (e.g. diamond)
· nonlinear elastic (e.g. rubber, cell membranes, bacterial cell walls)
· rigid-plastic (e.g. metals)
· elastic-plastic and strain-hardening (e.g. metals, polymers)
· elastic-brittle (e.g. ceramics, glasses)
· estimation of local mechanical properties (e.g. hardness, stiffness, yield, work of indentation, hysteresis, fracture toughness)

· Chapter 4 "Contact Mechanics," K. L Johnson, Cambridge University Press 1985

· Digital Instruments Application Note : "Nanoindenting, Scratching and Wear Testing Using Scanning Probe Microscopy"

17. Theory of the Elasticity of Single Macromolecular Chains I : The Freely-Jointed Chain (FJC) Model (CO)
· assumptions and definitions (e.g. statistical segment length, contour length, root-mean- square end-to-end distance)
· general statistical mechanical formulas
· Gaussian chain statistics
· non-Gaussian chain statistics
· extensibility
· effect of a and n on force curves

· manifestations in macroscopic mechanics (rubber elasticity)

· Ortiz handouts : A review of elasticity models for extension of single polymer chains
· Chapter 3 : The Elasticity of Long Chain Molecules (Flory Text)
· Chapter 6 : NonGaussian Chain Statistics and Network Theory, Treloar, L. R. G., The Physics of Rubber Elasticity, Clarendon Press, Oxford 1975.

18. Elasticity of Single Macromolecular Chains II : Cont'd (CO)
· the worm-like chain (WLC) : assumptions and definition of persistance length
· extensibility and comparison with FJC
· comparison of theory with experimental data on synthetic polymer chains (e.g. PS, PMAA, PEG, PVA)
· statistics of adsorption of polymer chains to surfaces

· same as above

19. Elasticity of Single Macromolecular Chains III : Biopolymers (CO)
· Markovian two-state thermodynamic models
· polysaccharides (e.g. Dextran, Xanthan, cellulose)
· elasticity of globular proteins (e.g. Titin, Tenascin)

· TBA

20. Elasticity of DNA : (CO)
· review of DNA structure
· theory and experiment
· single-stranded
· double-stranded (e.g. B-DNA to S-DNA strain-induced conformational transition)
· ionic effects
· torsional constraints (e.g. overwound "supercoiled" P-DNA and underwound)
· braided · energy of denaturation (melting)
· sequence-dependent mechanics
· molecular knots
· reptation (theory and experiment) and relaxation of stretched DNA
· molecular separation of complementary strands of DNA

· TBA

EXAM #2

ADDITIONAL SUPPLEMENTARY LECTURES GIVEN IN PAST YEARS :

Lateral Forces at the Atomic Scale : Friction :
· topographical effects
· Tomlinson's model
· friction between atomically flat surfaces
· stick-slip
· frictional force microscopy (e.g. self-assembled monolayers)

· Handouts from Nanoscience : Probing Friction and Rheology on the Nanometer Scale, Eds. E. Meyer, T. Gyalog, R. M. Overney, K. Dransfeld, World Scientific Publishers, 1999.

Intermolecular Interactions of Polymers :
· structure of polymers at surfaces : effect of grafting density (e.g. brushes, mushrooms), effect of grafting type (e.g. physisorbed, chemisorbed, telechelic)
· segment density versus distance plots (simulations)
· Alexander-de Gennes theory
· effect of temperature (relative to q-temperature) on force versus distance profiles
· comparison to experiment (e.g. PS, PEO, polyelectrolytes)

· TBA

Dynamic Force Spectroscopy : Nanorheology, Nanoconfinement, and Force Modulation :
· theoretical background, comparison with experimental data (e.g. polymer brushes)
· lubrication (e.g. disk drives)
· force modulation mapping (e.g. composites, polymer blends, biological materials)

· TBA

Directed Motion of Biological Structures : Molecular Motors :
· general overview : chemical, mechanical, and electrical
· Brownian Motion
· why are they needed?
·force velocity measurements
·kinesin-microtubule (*movie)
·acto-myosin
·DNA transcription by RNA polymerase
·bacterial flagella

· TBA

Atomistic Aspects of Fracture :
· summary of relevant length scales in fracture mechanics
· derivation of theoretical cleavage stress and comparison with experimental data
· molecular dynamics simulations (movies)

· TBA