Characterisation Programme 2006-2009 Polymer Multi-scale

Characterisation Programme 2006-2009Polymer Multi-scale Properties Industrial Advisory Group

28th June 2007

SE02: Improved Design and Manufacture of Polymeric Coatings Through the Provision of

Dynamic Nano-indentation Measurement Methods

Lead Scientist: Nigel Jennett

Project Manager: Rob Brooks

Wednesday, 12 September 2007

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Presentation outline

• Brief review of:– The project motivations– Instrumented indentation– SE02 Project outline

• Sensitivity study of parameters affecting dynamic indentation results

• Adaptation of NanoTest for variable rate, frequency and temperature dynamic indentation


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Nano-indentation applications

Ideal for measuring elastic and plastic properties of small volumes of materials, e.g. thin films and micro/nano-structures.• Coatings and Surface Engineering sectors / users, e.g.

Electronics, optics, automotive, aerospace, biomedical, pharmaceutical sectors..

• Local/surface properties of biological or polymeric materials (very soft, low force indentations)

• Micro-mouldings, nano-composites and ultra hard coatings where indentation depths are very small.

• Nano-mechanical testing of nano-engineered structures and materials

• Designers needing input data for models


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Instrumented Nanoindenter Schematic

StageLOAD FRAME

Magnet

Indenter

CapacitanceDisplacementGauge

Suspensionsprings

Sample

Coil

Current Source

Displacement sensor

Computer

Quasi-static

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0.73

loading unloading

samplesample

loading unloading

samplesample

loadingloading unloading

samplesample

loading unloading

samplesample

loading unloading

StageLOAD FRAME

Coil

Magnet

0.73

AreaForceHIT =

Cf

Frame

Compliance

SC CAE 11* ×∝

Contact

Area

Instrumented Indentation


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Schematic Indentation cycle

0.73

Cf

Creep / Viscosity


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Standard Polymers: quasi-static responseLoad Vs. Depth Curves

0

0.5

1

1.5

2

2.5

0 500 1000 1500 2000 2500 3000 3500

Depth (nm)

Load

(mN

)

PS - 1PS - 3PS - 4


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Motivation• Requirement for local polymer properties in part

design:-– bearings, gears, cams, press-fit parts, composites (matrix

and interfaces)• Requirement for properties of small volumes

– e.g. mico-mouldings, packaging, coatings.• Production control and QA via sensitivity of surface

to production parameters. – Thermal history affects surface properties and can be

detected by indentation.

Nanoindentation has the resolution but polymers have time/rate dependent properties.

⇒ Dynamic measurement methods are required!


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Instrumented (Nano)indenter Schematic

StageLOAD FRAME

Magnet

Indenter

CapacitanceDisplacementGauge

Suspensionsprings

Sample

Coil

Current Source

Displacement sensor

Computer

Quasi-static

Oscillator

Lock-in amplifier

/ Dynamic


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Scientific Objectives• Validate indentation protocols for measuring loss

and storage modulus and time constants of visco-elastic materials and feed into:

• ISO standardisation (new work item)• Development of 1GPa certified reference material

• Compare methods to measure polymer properties as a function of frequency and temperature.

• Develop ultra-rapid indentation and creep-relaxation measurement methods for characterisation of visco-elastic materials.



Dynamic Calibration #1 Support spring stiffness (Ks) = 43.12 N/m Indenter mass (m) = 0.0073 KgDamping Coefficient (C ) = 3.73 Ns/m

1 10 100 1000

10-4

10-3

10-2

1/mw2

1/Ciw

Data: Final_BModel: user1Equation: y=1/((P1-P2*x^2)^2+(x*P3)^2)^0.5Weighting: y No weighting Chi^2/DoF = 3.3348E-9R^2 = 0.99995 P1 43.11764 ±0.10679P2 0.00728 ±0.00094P3 3.73455 ±0.0149D

ynam

ic C

ompl

ianc

e (h

0/F0)

Frequency, w (rad/sec)

Free Hanging Indenter

1/Ks

1/Diw

i



Dynamic Calibration #2 Damping Coefficient vs. Position

Di = Do + D1x + D2x2 + D3x3 Ns/m

-3 -2 -1 0 1 2 33.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5Polynomial Regression for Data2_B:Y = A + B1*X + B2*X^2 + B3*X^3 + B4*X^4

Parameter Value Error t-Value Prob>|t|---------------------------------------------------------------------------A 3.76138 0.00617 609.99994 <0.0001B1 0.02458 0.0046 5.34438 <0.0001B2 0.28443 0.00404 70.36398 <0.0001B3 -0.00489 7.32653E-4 -6.67395 <0.0001B4 0.00736 4.72118E-4 15.59502 <0.0001---------------------------------------------------------------------------

R-Square(COD) Adj. R-Square Root-MSE(SD) N---------------------------------------------------------------------------0.99971 0.99967 0.01827 31---------------------------------------------------------------------------

Dam

ping

Coe

ffici

ent,

C1 (N

s/m

)

Indenter Position (V)

Di



Spring and dashpot modelE′= Storage modulusE″= Loss modulusδ = Phase shiftTan δ = Damping coefficient

( ) ( )( )ωωωδ

EE

′′′

=tan

( )εσ EiE ′′+′=

( )2222

0

0 ωω mKDhF

si −+=

DiKs

m

S Ds

Kf

-4

-3

-2

-1

0

1

2

3

4

0 10 20 30 40 50 60 70 80 90 100

Time (milli-seconds)

Forc

e ( µ

N) /

Dis

plac

emen

t (nm

)

DisplacementLoad

Phase Shift

Amplitude

h(t)

F(t)



Dynamic contact mechanics

δ )(2'

chASE π

=ωDs Storage Modulus

S

)(2''

c

s

hADE πω

= Loss Modulus

Results are available point wiseOr by plotting S or D vs.√A(hc)



Storage modulus by graphical method

y = 4E-06x - 0.0003R2 = 0.9997

y = 3E-06x + 0.0001R2 = 0.9995

0.0E+00

5.0E-03

1.0E-02

1.5E-02

2.0E-02

2.5E-02

0 1000 2000 3000 4000 5000 6000 7000 8000

sqrt (Contact Area)

Con

tact

Stif

fnes

s (m

N/n

m)

PS - 1 E = 2.5 GPaPS - 3 E = 0.21 GPa

3.9 GPa

2.3 GPa



Loss Modulus by graphical method

y = 3E-07x + 0.0005R2 = 0.9962

y = 1E-07x + 0.0004R2 = 0.951

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0 1000 2000 3000 4000 5000 6000

Sqrt (Contact Area)

Dam

ping

(mN

/nm

)

PS - 1PS - 3

E'' = 0.12 GPa

E'' = 0.31 GPa



0 100 200 300 400 500 600 700 8000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0

2000

4000

6000

8000

10000

12000

14000

16000O

scill

atio

n A

mpl

itude

(nm

)

Amplitude: dF = 0.3 µ N dF = 1 µ N dF = 3 µ N

Indentation Depth (nm)

Stifness:dF = 0.3 µ NdF = 1 µ NdF = 3 µ N

Stif

fnes

s (N

/m)

PS1: Stiffness dispersion vs. drive amplitude



0 100 200 300 400 500 600 700 8000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

-500

0

500

1000

1500

2000Damping:

dF = 0.3 µ NdF = 1 µ NdF = 3 µ N

Osc

illat

ion

Am

plitu

de (n

m)

Indentation Depth (nm)

Amplitude:dF = 0.3 µ NdF = 1 µ NdF = 3 µ N

Dam

ping

(N/m

)

PS1 Damping dispersion vs. drive amplitude



PS - 3

0

2000

4000

6000

8000

10000

12000

14000

16000

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Amplitude (nm)

S, D

(N/m

)

Stiffness (N/m)Damping (N/m)

PS3 Data uncertainty vs. drive amplitude



0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Amplitude (nm)

S, D

(N/m

)

Stiffness (N/m)Damping (N/m)Stiffness F = 3 uNDamping F = 3 uN

Effect of amplitude on dispersion PS3



10 100 1000

-0.0020.0000.0020.0040.0060.0080.0100.0120.0140.0160.0180.0200.0220.0240.0260.028

( )2222

0

0 ωω mKchF

−+= Run1 Run2 Run3 Run4 Run5 Run6 Run7

Dyn

amic

Com

plia

nce

(m/N

)

Frequency (rad/sec)

Sensitivity to static calibrationAC Force Cal. AC Displacement Cal

57000 1200047000 1500052000 1350057000 1500052000 1350047000 1200052000 13500



Er' and Er'' calculated from slope of Stiffnes and DamRun Factor 1 Ko (N/m) Factor 2 m (Kg)

1 44.5 0.0082 42 0.0053 44.5 0.0084 47 0.0055 44.5 0.0086 42 0.0117 47 0.0118 53.87 0.008579 35.55 0.0058

Original 43.12 0.00728

Sensitivity of E’, E” to dynamic calibration

Software sensitivitydesign

Run Factor 1 Ko (N/m) Factor 2 m (Kg)1 44.5 0.0082 42 0.0053 44.5 0.0084 47 0.0055 44.5 0.0086 42 0.0117 47 0.0118 53.87 0.008579 35.55 0.0058

Experimental Sensitivitydesign



PS - 1, 0.5 mN max load, 0.05 s-1 strain rate

00.5

11.5

22.5

33.5

44.5

5

0 100 200 300 400 500

Displacement (nm)

E' (

GP

a)

Run1Run2Run3Run4Run5Run6Run7Run8Run9F = 3 uN -0.0004

-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0 500 1000 1500

Area ^1/2

Dam

ping

(mN

/nm

)

Series1Series2Series3Series4Series5Series6Series7Series8Series9F = 3 uN

PS - 3

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0 500 1000 1500 2000Area ^ 1/2

Dam

ping

(mN

/nm

)

Series1Series2Series3Series4Series5Series6Series7Series8Series9F = 3 uN

PS - 3, 0.5 mN max load, 0.05 s-1 strain rate

0

0.5

1

1.5

2

2.5

3

0 200 400 600 800 1000Displacement (nm)

E' (

GP

a)

Run1Run2Run3Run4Run5Run6Run7Run8Run9F = 3 uN

Experiment D.o.E



PS3

-0.00010

0.00010.00020.00030.00040.00050.00060.00070.00080.00090.001

0 200 400 600 800 1000 1200Area ̂1/2

Dam

ping

(mN

/nm

)

Run1Run2Run3Run4Run5Run6Run7Run8Run9

PS - 1

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0 1000 2000 3000 4000Area ^ 1/2

Stif

fnes

s (m

N/n

m)


PS-1

-0.0004

-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0 200 400 600 800 1000Area ^ 1/2

Dam

ping

(mN

/nm

)


PS - 3

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0 2000 4000 6000 8000Area ^ 1/2

Stif

fnes

s (m

N/n

m)

Run1

Run2

Run3

Run4

Run5

Run6

Run7

Run8

Run9

Li

Software D.o.E



Supplementary Data Acquisition

Supplementary DAQ System

÷2

NanoTest Control Box

Interface

Ultra-fast dynamic indentation



ON

Dynamic indentation

NanoTest (Micro Materials Ltd, Wrexham)

• Dynamic nanoindentation• High and low rate indentations• Displacement monitored with timevs. Lock-in amplifier Amplitude & Phase

Test Variables

• Impact energy• Oscillation Frequency• Strain rate• Test probe geometry• Temperature



OFF

Dynamic indentation

NanoTest (Micro Materials Ltd, Wrexham)

• Dynamic nanoindentation• High and low rate indentations• Displacement monitored with timevs. Lock-in amplifier Amplitude & Phase

Test Variables

• Impact energy• Oscillation Frequency• Strain rate• Test probe geometry• Temperature



High-temperature Testing:0.1 mN to 20 N

MicroMaterials NanoTestHot stage – sample temp ≤500°C

Force

Heaters

Depthsensor

Mapping the hardness of tribological coatings

5.2 micron Ion-beam Assisted Deposition (IBAD) Alumina; Stephen Abela, Unversity of Malta

Harder phase to provide abrasive resistance

Softer phase to provide toughness

H(GPa)

ScanScan



Stage PlansStage 1 (1/4/06 – 31/6/07)

Selection/procurement of materials

Calibration and algorithm sensitivity studies

Development of dynamic calibration method (NPL Report)

Stage 2 (1/4/07 – 31/3/08) Design and test temperature stage

Development of ultra-rapid indentation method

Frequency, sweep and chirp

High rate indentation method (scientific paper)

Stage 3 (1/4/08 – 31/3/09)Visco-elastic models

Evaluation of temperature stage

High Rate indentation method at elevated temperatures (scientific paper)

Validated protocols/Input to ISO standards



Industrial involvement

• Materials supply– Highly reproducible “standard” polymers– Industrial components / materials

• Collaboration for characterisation comparisons– Property data from other test methods as function

of frequency and temperature

• Case studies / feasibility of adoption of method



DeliverablesProject Description

D1: Validated protocols for room temperature measurement of mechanical properties of polymer surfaces or coatings (NPL Report).

D2: Refinement of current methods into intelligent miniaturised tests (scientific paper).

D3: Mechanical properties of polymer surfaces or coatings as a function of temperature (scientific paper).



SE02 GANNT chart

Documents

Characterisation Programme 2006-2009 Polymer Multi-scale