Local Piezoelectric Response and Elastic Properties as Measured with AFM

1
Local Piezoelectric Response andElastic
Properties asMeasured with AFM

• Emily Smith
• eas48_at_drexel.edu
• Advisor Dr. Spanier

2
Problem Statement

• Techniques to measure local properties of bone
• Correlation with hierarchical structures
• Piezoelectricity connection with bone growth

3
What is Bone?

• Collagen
• Protein
• Hydroxyapatite
• Ca-phosphate mineral
• Types
• Cortical
• Cancellous

http//silver.neep.wisc.edu/lakes/BME601.html
4
Bone

• Hierarchical Structure

Rho, Jae-Young, Liisa Kuhn-Spearing and Peter
Zioupos. Mechanical properties and the
hierarchical structure of bone. Mechanical
Engineering Physics. 20 (1998) 92-102.
5
Bone Cells

• Osteoclasts
• Breaks down and removes bone material
• Osteoblasts
• Forms new bone material
• Osteocytes
• Senses problems and pressure in the bone

http//depts.washington.edu/bonebio/bonAbout/bonec
ells.html
6
Microscope Image of Bone Cells
http//depts.washington.edu/bonebio/bonAbout/bonec
ells.html
7
Principle of AFM
http//www.npl.co.uk/smd/npl_research/afm_theory.h
tml
8
Atomic Force Microscopy

• Scan probe microscopy
• Three Topographic Modes
• Contact
• AC Intermittent
• AC Non-contact

www.asylumresearch.com
9
Force vs. Tip-Sample Separation
C- Contact IC Intermittent Contact NC
Non-contact

• Catalin Harnagea. Local piezoelectric response
  and domain structures in ferroelectric thin films
  investigated by voltage-modulated force
  microscopy. Ph.D. thesis. 2001

10
Piezoelectricity

• Piezoelectric
• Mechanical Stress gt Electric Field
• Equation D d s
• Converse Piezoelectric Effect
• Equation x d E
• Ferroelectric
• Spontaneous Dipole Moment
• Domains

11
Elasticity

• Ratio of stress and strain
• Ability to return to its original shape
• Current ways to measure

Strength
Stress
Elastic Range
Strain
http//hotmix.ce.washington.edu/wsdot_web/Modules/
04_design_parameters/04-2_body.htmelastic_modulus
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Piezoresponse Scan Principle

• AC voltage
• Conductive Tip
• Contact Mode

13
Scan of Sample Lamella of Cortical Bone
Line cross-section of scan Shows height
Rho, Jae-Young, Liisa Kuhn-Spearing and Peter
Zioupos. Mechanical properties and the
hierarchical structure of bone. Mechanical
Engineering Physics. 20 (1998) 92-102.
14
Example of Piezoresponse Scan
a- Topographic image of a Bi4Ti3O12
grain (line added) b- The domain
structure

• Catalin Harnagea. Local piezoelectric response
  and domain structures in ferroelectric thin films
  investigated by voltage-modulated force
  microscopy. Ph.D. thesis. 2001

15
Piezoelectric Response in Bone

• Topography
• (b)/(c) Piezoresponse Scan

C. Halperin, S. Mutchnik, A. Agronin, M.
Molotskii, P. Urenski, M. Salai, and G. Rosenman.
Piezoelectric Effect in Human Bones Studied in
Nanometer Scale. Nano Letters. 4 (2004) 1253-6.
16
Future Work

• Piezoelectric Response
• Piezoelectric coefficient
• Elasticity measurement

17
Literature

• Jae-Young Rho, Liisa Kuhn-Spearing and Peter
  Zioupos. Mechanical properties and the
  hierarchical structure of bone. Mechanical
  Engineering Physics. 20 (1998) 92-102.
• Catalin Harnagea. Local piezoelectric response
  and domain structures in ferroelectric thin films
  investigated by voltage-modulated force
  microscopy. Ph.D. thesis. 2001
• C. Halperin, S. Mutchnik, A. Agronin, M.
  Molotskii, P. Urenski, M. Salai, and G. Rosenman.
  Piezoelectric Effect in Human Bones Studied in
  Nanometer Scale. Nano Letters. 4 (2004) 1253-6.
• http//silver.neep.wisc.edu/lakes/BME601.html
• http//depts.washington.edu/bonebio/bonAbout/bonec
  ells.html
• http//www.npl.co.uk/smd/npl_research/afm_theory.h
  tml
• www.asylumresearch.com
• http//hotmix.ce.washington.edu/wsdot_web/Modules/
  04_design_parameters/04-2_body.htmelastic_modulus