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Nanoscale Thermal Analysis
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Nanoscale Thermal Analysis
Quantitative Nanoscale Property Mapping
with Automated Transition Temperature Microscopy
Thomas Mueller, Ph.D., Product Line Manager, Bruker Nano Surfaces
Agenda
1. Introduction
a. AFM for polymers
2. Bruker Nano Thermal Analysis
a. Operating Principle
b. Application Examples
c. Correlation With Bulk Measurements
3. Transition Temperature Microscopy
a. Operating Principle
b. Application Examples
c. Quantification
4. Summary & Conclusions
Bruker NanoSurfaces Division 2/15/2012 2
Introduction to AFM: Tool for Nanoscale Topographic Information
2/15/2012 3 Bruker NanoSurfaces Division
Array of engineered DNA, 2m scan
Monolayer of C60H122 alkane, 600nm scan
Atoms on HOPG, 8nm scan
Introduction to AFM: What you want to know about polymers - quantitative nanomechanical properties
2/15/2012 4 Bruker NanoSurfaces Division
PeakForce QNM can quantitatively and unambiguously identify modulus and
adhesion variations. Phase imaging and multifrequency imaging techniques cannot.
Comparison of the adhesion and phase images clearly shows that the phase contrast
is primarily due to adhesion, whereas one
might more commonly assume that it reflects
modulus variations
Section plot illustrates ability to measure the modulus across the polymer layers
PFQNM-Height
PFQNM-Adhesion
PFQNM-Modulus
Tapping-Height
Tapping-Phase
Multilayered polymer film,
10 m scans
Left: PeakForce QNM
Right: TappingMode
Introduction to AFM: What you want to know about polymers - electrical properties
2/15/2012 5 Bruker NanoSurfaces Division
Current map on PEDOT-P3HT overlaid on nm-scale topography.
Achieving highest resolution in topography and current (2mm image size, 10nm height scale, 5pA current scale)
Very soft samples cannot be imaged in contact mode based CAFM.
Only possible with PeakForce TUNA.
High-resolution current mapping on organic photovoltaics
Enabled by PeakForce TUNA and ppm-level environmental control
Sample courtesy of Prof. Nguyen, UCSB
Introduction to AFM: What you want to know about polymers - thermal properties? chemistry?
2/15/2012 6 Bruker NanoSurfaces Division
6
Topography
Quantitative nanomechanics PFQNM
Nanoscale electrical properties PFTUNA
Thermal properties Tg, Tm
What is it Chemistry
Influence of processing, wear, UV exposure on component distribution, aggregation etc
Conventional Material Analysis Quantitative, bulk
2/15/2012 7 Bruker NanoSurfaces Division
TMA
Material-specific information, but no spatial resolution
Thermal Mechanical Analysis (TMA) setup shown
Bringing Thermal Analysis to the Nanoscale The Tip
2/15/2012 8 Bruker NanoSurfaces Division
V I
I
Topography Phase
Controllable probe temperatures up to
400C
0.7 mm scan
Bringing Thermal Analysis to the Nanoscale Operating Principle
2/15/2012 9 Bruker NanoSurfaces Division
Current
Heater
control
Deflection
High-Resolution
AFM Image
Local Tg & Tm
Temperature
measurement
Nanoscale Thermal Analysis Solutions
Bruker NanoSurfaces Division 2/15/2012 10
PS/LDPE Blend on Silicon Clear ID Domain vs Matrix
2/15/2012 11 Bruker NanoSurfaces Division
8 x 4 m Scan
Domains (LDPE, Tm)
Matrix (PS, Tg)
Before
After
Food Packaging Understand/Design/(Reverse-)Engineer Starting with AFM
2/15/2012 12 Bruker NanoSurfaces Division
Distinct layers, distinct fine structure. Material and function?
Food Packaging Understand/Design/(Reverse-)Engineer Nanothermal Analysis
2/15/2012 13 Bruker NanoSurfaces Division
30m scan
VITA clearly distinguishes
the two outside layers
from the inside one.
VITA provides
quantitative local Tm,
aiding material ID.
In packing applications
the outside layers often
consist of HDPE and the
inside (barrier) layer is
EVOH.
Toner Particle Analyzing Composition and Core Shell Structure
2/15/2012 14 Bruker NanoSurfaces Division
Sample: Toner particles embedded
in epoxy and microtomed
Toner Particle
Center Region
Middle layer
Outer layer
Epoxy
74.3 C
70.4 C
60.4 C
15 x 7.5 m topographic scan
Nanoscale Drug Analysis Formulation: Crystallinity
2/15/2012 15 Bruker NanoSurfaces Division
Data courtesy of M. Reading, D Craig and L. Harding, UEA
The existence of different solid-state forms, such as polymorphs, solvates, hydrates,
and crystallinity in pharmaceutical drug substances and excipients, have
downstream consequences in drug products and biological systems.
Crystalline only Crystalline and amorphous
Indomethacin
PEO/SPP Blend (1) Microscale Analysis
2/15/2012 16 Bruker NanoSurfaces Division
15 m Scan Domains (PEO, Tm)
Matrix (sPP, Tm)
PEO/SPP Blend (2) Uncovering Additional Nanoscale Variation
2/15/2012 17 Bruker NanoSurfaces Division
Height 4 m Scan Phase
sPP Melt Transition
PEO Melt Transition
Measurement Location
Small PEO
domains on sPP
Correlation with Bulk Thermal Analysis Validation of nano-TA
2/15/2012 18 Bruker NanoSurfaces Division
Three crystalline samples and three amorphous samples were measured by bulk ThermoMechanical Analysis (TMA) and compared against VITA measurements
y = 1.0088x - 3.8173
R2 = 0.9811
y = 1.0027x + 0.2778
R2 = 0.9701
y = 1.0047x + 2.9657
R2 = 0.95810
50
100
150
200
250
300
0.0 100.0 200.0 300.0
TMA onset
Nan
oT
a O
nset
0.1C/s
1C/s
10C/s
Slopes: 1.003 - 1.009
Offsets: -4 to +3C
Data courtesy of G. Meyers and A. Pasztor, DOW
Summary Nanothermal Analysis Quantitative characterization & material ID
2/15/2012 19 Bruker NanoSurfaces Division
Nanothermal analysis provides phase transition temperatures (Tg/Tm) with sub-100nm resolution
Enables local material identification in heterogeneous samples for R&D or Failure Analysis, in blends/composites/multilayers
Good correlation with results from standard Bulk TMA, a trusted method at macro-level
High probe temperature enables use with most polymers
But Thats Not All Missing a Key Part
2/15/2012 20 Bruker NanoSurfaces Division
Thermal property variations may not correlate with topography
Neither bulk nor single-point nanoscale measurements capture the distribution of properties
Nanoscale property variation is intrinsic to polymers
How much more
complexity in this
PEO/SPP blend?
Transition Temperature Microscopy Completing the Picture with Fast Automated Mapping
2/15/2012 21 Bruker NanoSurfaces Division
AFM Configurations for
Transition Temperature Microscopy
Bruker NanoSurfaces Division 2/15/2012 22
Transition Temperature Microscopy
Applications Example (1)
1. Multilayer films revisited
Complex: support, adhesive, functional layers
Here: reveal property variation in tie layer
Obtain complete property distribution
Bruker NanoSurfaces Division 2/15/2012 23
1. Navigation & point / array selection
Import AFM image to navigate and define locations for initial single point measurements.
Bruker NanoSurfaces Division 2/15/2012 24
2. Automatic peak softening detection
Automatic peak detection guarantees unbiased extraction of transition temperatures from raw data.
Bruker NanoSurfaces Division 2/15/2012 25
3. Embedded cursor for effortless data mgt
Retains information about location of measurements, guaranteeing correct spatial correlation in analysis post acquisition.
Bruker NanoSurfaces Division 2/15/2012 26
4. TTM mapping for structure property correlation
Fully automated acquisition and analysis. Reveals transition temperature variations within the tie layer that would not have been expected or predicted based on AFM image alone or based on single point nano-ta measurements.
Bruker NanoSurfaces Division 2/15/2012 27
37 70 103 136 169 202 235
6. Histogram analysis
Provides complete statistics on nanoscale thermal property variation, characterizing variations within each layer.
Note: Currently released version provides the measurement data. Built-in histogram function planned for next SW release.
Bruker NanoSurfaces Division 2/15/2012 28
Transition Temperature Microscopy
Applications Example (2)
2. Solvent recrystallized surface
Surface modification and coatings are common
Evades bulk characterization
Here: gradient of solvent concentrations, nontrivial property distribution
Bruker NanoSurfaces Division 2/15/2012 29
Solvent Crystallization Example
Spatial Variation
Transition temperature microscopy maps out surface thermal properties after crystallization. Sample was exposed to gradient of high (left) to low (right) solvent concentrations resulting in measurable increase in softening temperature.
Bruker NanoSurfaces Division 2/15/2012 30
Solvent Crystallization Example
Histogram Analysis
Bruker NanoSurfaces Division 2/15/2012 31
Quantifying thermal property distribution as function of surface treatment
Transition Temperature Microscopy
Applications Example
3. Pharmaceutical copolymer
In-situ measurement on pharmaceutical delivery vessel
Elucidates variation in copolymer blending that is not obvious from other measurements
Bruker NanoSurfaces Division 2/15/2012 32
Pharmaceutical Copolymer
Spatial Variation
Bruker NanoSurfaces Division 2/15/2012 33
AFM does not reveal obvious variation in mixing and the rough surface of the in situ sample (sectioning not an option) presents a challenge to mechanical measurements and phase imaging.
Transition temperature microscopy clearly shows spatial variations in thermal properties indicating variation in copolymer mixing.
Pharmaceutical Copolymer
Histogram Analysis
Bruker NanoSurfaces Division 2/15/2012 34
Systematic, automated execution of literally 100s of nano-ta measurements provides valid statistics, allowing true quantification of thermal property distribution and therefore mixing variation.
Summary
Quantitative Sample Characterization with TTM
Transition temperature microscopy reveals nanoscale spatial variation in thermal properties
Those variations may not be reflected in other (mechanical, electrical) AFM property measurements, so single point nanothermal measurements with location chosen based on an AFM image would miss them.
Transition temperature microscopy provides fully automated execution of large numbers of nanoscale thermal measurements
Uncovers new information beyond single point and average quantities: The finite property distribution that is intrinsic to polymers and relevant to their application in many cases.
Transition temperature microscopy perfectly complements Brukers exclusive PF QNM and PFTUNA
Making Dimension Icon and MultiMode8 the platforms that provide the most complete property information on polymer samples
Bruker NanoSurfaces Division 2/15/2012 35
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