lescc presentation 2 16-2010

Expert Vision for a Changing World

AFM Applications for Polymer and Particle Systems

PolyInsight LLC526 South Main Street, Suite 414

Akron, Ohio 44311(330) 777-0025

[email protected]://polyinsight.com

Michael P. Mallamaci, Ph.D.

February 16, 2010Society of Cosmetic ChemistsLake Erie Chapter

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Agenda

• Brief History of PolyInsight• Atomic-Force Microscopy (AFM)

– Surface characterization technique– Internal structure technique

• Using AFM in Cosmetic Science– Particulate gels in polymer modifiers– Surface structure of different nail polishes – Surface structure of human hair– Internal structure of human hair

• Summary / Q & A


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PolyInsight

• Small team of experts in the physical and chemical structure of rubber and plastics

• Laboratory operation with several microscopes and related sample preparation equipment in-house

• Located in Akron, Ohio at the Akron Global Business Accelerator

• Partnerships with The University of Akron and other regional laboratories providing additional instrument access


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PolyInsight (cont’d)

• Continuous operation since July 2003• Services include:

– Failure Analysis– Atomic-Force Microscopy (AFM)– Polymer and Chemical Analysis– Consulting and Litigation Support

• Developed a portfolio of over 50 clients nationally and overseas

• Medical/Healthcare, Automotive, Industrial Coatings, and Consumer Products


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Atomic-Force Microscopy (AFM)

• High spatial resolution imaging of surface topography

• Similar to stylus profilometry, except 1 nm resolution

• Probe interacts with surface to reveal mechanical properties at high resolution


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Change in amplitudeChange in amplitudeprovides topographyprovides topography

Lag in phase relatedLag in phase relatedto viscoelasticityto viscoelasticity

or material stiffnessor material stiffness

Free amplitude = Free amplitude = AAooDamped amplitude atDamped amplitude atsetpoint S = setpoint S = AAss

AAoo AAssPhase lag


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Veeco Dimension 3000 AFM(large sample sizes)

Veeco MultiMode AFM(highest spatial resolution)


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Surface Characterization via AFM

• The height of surface features can be measured quantitatively with 0.1 nm resolution

• Atomic step heights on crystals, DNA molecules, proteins, semiconductor lithography applications

• Maximum height of features allowed is ~ 6 µm, so surfaces must be “smooth”


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Roughness Analysis – Surface of Polymer Stent


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NIST Gold –

30nm spheres


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Nano-drug particles –

unknown size


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Particle size analysis using Veeco Nanoscope

software


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Internal Structure via TEM

• Classic technique for examining the structure of composite materials is Transmission-Electron Microscopy (TEM)

• Materials must be thinned to ~ 100 nm or less to be electron transparent

• Image contrast is based on either electron diffraction (crystalline materials) or mass-density (amorphous materials)


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Internal Structure of Soft Materials via TEM

• Sample preparation technique for obtaining electron transparent thin sections is cryoultramicrotomy

• Mass-density image contrast is enhanced by using heavy-metal stains, such as RuO2 or OsO4

• TEM offers highest spatial resolution possible at < 0.1 nm, plus chemical ID techniques

• Time-consuming sample preparation ($$$)• Difficulty with complex multi-component systems


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Internal Structure of Soft Materials via AFM

• Probe interaction with the surface can image “mechanical property” distribution with high spatial resolution (1-5 nm)

• Cryoultramicrotomy must be used to expose the internal structure – cut open in cross-section and look at the surface

• Relies on surface structure being representative of internal structure (just like polished sections)


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Internal Structure of Soft Materials via AFM

• Incompatible 4 component polymer blend can be imaged– PP (brightest)– PA (round, less

bright)– PE (dark orange)– SEBS (black,

surrounds PA)


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Review of AFM Capabilities

• High spatial resolution imaging of surfaces• Quantitative measurement of surface

roughness and particles on substrates• Imaging of internal structure based on

mapping of mechanical properties• Complex structures can be imaged, no

stains required• Environmental control possible: air, inert

gas, temperature


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Using AFM in Cosmetic Science

• Particulate gels in polymer modifiers– Appearance, processing

• Surface structure of different nail polishes– Reflectivity, composition

• Surface structure of human hair– Damage, deposits

• Internal structure of human hair– Dyeing


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Particulate gels in polymer modifiers


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Particulate gels in polymer modifiers


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Particulate gels in polymer modifiersBadGood


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Surface structure of different nail polishesClear top coat


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Surface structure of different nail polishes“Metallic silver” pigment in top coat


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Structure of Hair


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Surface structure of human hair

Scales

Deposit


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Surface structure of human hair


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Internal structure of human hair

Cuticle

Cortex


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Cuticle

Cortex


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Cortex


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Summary

• AFM has unique strengths as a high resolution microscopy technique

• Routine use as a tool for cosmetic chemists is possible: can “see” things that other techniques cannot

• Offers quantitative microscopic measurement tool for “soft” cosmetic systems

lescc presentation 2 16-2010

Documents

lake erie chapter

height of surface features

afm incompatible

chemical structure of

nm resolution probe

afm probe interaction

nm cryoultramicrotomy

tem classic technique