AFM for Polymers - McCrone · Atomic force microscopy for polymers • AFM has become a staple for...
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AFM for Polymer Characterization and Analysis Dalia Yablon SurfaceChar LLC, Sharon MA [email protected]
Transcript of AFM for Polymers - McCrone · Atomic force microscopy for polymers • AFM has become a staple for...
AFM for Polymer
Characterization and
Analysis
Dalia Yablon
SurfaceChar LLC, Sharon MA
Atomic force microscopy for polymers
• AFM has become a staple for polymer characterization labs, alongside electron and optical microscopy, in both industrial and academic labs
• AFMs are often the dominant characterization technique in QC and analytical labs that handle polymers
• Well-known pros:
– Nanometer lateral resolution
– Angstrom vertical resolution
– Non-destructive imaging
– Flexible environment• Air/fluid/vacuum
SEM TEM AFM/SPM
sample prep/ requirements conductive coating thin sectioning smooth
resolution nm angstrom 5nm
morphology yes yes yes
chemical specificity yes yes no
true height (Z) no no yes
vacuum needed? yes yes no
mechanical properties no no yes
What are some of the most common properties
AFM can measure on polymers?
Topography
Most common measurement
AFM provides true measurement of z
(height)
Enables measurements like roughness
analysis
Topography Phase
Multilayer PE sample, from AZO Materials
Morphology based on mechanical or
material contrastChemical contrast or contrast based on Z
can be hard to obtain for polymers
Mechanical properties are very different –
use that as a basis for contrast
(Mechanical properties)Stiffness (modulus), adhesion,
viscoelasticity
Lateral resolution: 10nm, vertical resolution: <1nm
AFM - Principles of operation
piezo
Phase Imaging
Tire tread
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Topography
Phase
Phase image shows contrast based on:
adhesion, stiffness (modulus), dissipation,
viscoelasticity
Phase imaging of tire tread– Materials are becoming more complicated in terms of blends and composites
– Some materials have upto 7 components with a very wide modulus range (10
MPa- 100GPa)
– Can we find all 5 components in this material?
Component #1 and #2
Component #3
Component #4Component #5
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Phase image of impact copolymerImpact copolymer
Size, morphology, dispersion of rubber domains with PP matrix
Affects macroscale performance properties (structure-property relationships)
AFM characterization serves as a quality control during product formulation and
Failure analysis From D. Yablon, “SPM for critical measurements in the semiconductor industry”, chapter 9
From “SPM in Industrial Applications” (2013, Wiley, Yablon)
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Image analysis
Radius Length
Aspect ratioArea
Rubber domains colored by radius
Can analyze dozens of parameters on domains/particle size to get
Statistics on geometry, volume, etc
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AFM imaging of block copolymers
1um 1um
Phase image of SEBS block copolymer
D. Wang et al. / Polymer 53 (2012) 1960
Phase image of P3HT-b-PPerAcr
Gupta et al., ACS Appl. Mater. Interfaces
2015, 7, 12309−12318
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Impact copolymer under tensile stress
10 um
Measure strength of interface between E-P rubber and PP matrix
Observe crazing in PP matrix
From D. Yablon, “SPM for critical measurements in the semiconductor industry”, chapter 9
From “SPM in Industrial Applications” (2013, Wiley, Yablon)
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In situ AFM of polymer dynamics
Journal of Applied Polymer ScienceVolume 133, Issue 48, 22 AUG 2016 DOI: 10.1002/app.44269http://onlinelibrary.wiley.com/doi/10.1002/app.44269/full#app44269-fig-0001
65C 75C
85C 95C
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Ultrathin PE films on graphite
Ann-Kristin Löhmann et al. PNAS 2014;111:17368-17372
height T=120C
On droplet
surface
Through
droplet
T=115C
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High resolution AFM imaging of
PE lamellae
Hobbs et al., Physics Review Letters, p. 197801, 2011
(110) Surface of a crystalline PE lamella
5nm 10nm
Interface between crystalline and
Amorphous region
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Summary
• AFM is a powerful nanoscale microscopy method based on a mechanical interactions between the tip and the sample
• AFM is particularly useful for polymer characterization since many polymer materials can be differentiated based on their materials properties instead of their chemistry
• Applications shown to probe morphology and structure-property relationships of tire materials, impact copolymers, block copolymers, and polyethylene lamellae
• Environmental flexibility a powerful capability in AFM to explore kinetics and dynamics of polymer processes – in situ microscopy
– Imaging in fluidic environments
– Imaging at temperatures
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AFM course March 21-23, 20173 day intensive laboratory based course at Hooke
College of Applied Sciences in Westmont, IL
Questions about course: [email protected] or [email protected]
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Polymer blend
AFM easily distinguishes between 3 polymer blend: iPP, HDPE, PS
PS
PE
PP
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