AFM Applications for Polymer and Particle Systems Michael P. - - PowerPoint PPT Presentation

Expert Vision for a Changing World

AFM Applications for Polymer and Particle Systems

PolyInsight LLC 526 South Main Street, Suite 414 Akron, Ohio 44311 (330) 777-0025 mike@polyinsight.com http://polyinsight.com

Michael P. Mallamaci, Ph.D.

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 2 of 30

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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 3 of 30

PolyI nsight

• 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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 4 of 30

PolyI nsight (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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 5 of 30

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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 6 of 30

Atomic-Force Microscopy (AFM)

Change in amplitude Change in amplitude provides topography provides topography Lag in phase related Lag in phase related to viscoelasticity to viscoelasticity

• r material stiffness
• r material stiffness

Free amplitude = Free amplitude = A Ao

• Damped amplitude at

Damped amplitude at setpoint S = setpoint S = A As

s

A Ao

• A

As

s

Phase lag

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 7 of 30

Atomic-Force Microscopy (AFM)

Veeco Dimension 3000 AFM (large sample sizes) Veeco MultiMode AFM (highest spatial resolution)

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 8 of 30

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”

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 9 of 30

Surface Characterization via AFM

Roughness Analysis – Surface of Polymer Stent

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 10 of 30

Surface Characterization via AFM

NIST Gold – 30nm spheres

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 11 of 30

Surface Characterization via AFM

Nano-drug particles – unknown size

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 12 of 30

Particle size analysis using Veeco Nanoscope software

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 13 of 30

I nternal 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)

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 14 of 30

I nternal 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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 15 of 30

I nternal 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)

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 16 of 30

I nternal 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)

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 17 of 30

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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 18 of 30

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

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 19 of 30

Particulate gels in polymer modifiers

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 20 of 30

Particulate gels in polymer modifiers

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 21 of 30

Particulate gels in polymer modifiers

Bad Good

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 22 of 30

Surface structure of different nail polishes

Clear top coat

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 23 of 30

Surface structure of different nail polishes

“Metallic silver” pigment in top coat

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 24 of 30

Structure of Hair

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 25 of 30

Surface structure of human hair

Scales Deposit

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 26 of 30

Surface structure of human hair

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 27 of 30

I nternal structure of human hair

Cuticle Cortex

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 28 of 30

I nternal structure of human hair

Cuticle Cortex

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 29 of 30

I nternal structure of human hair

Cortex

February 16, 2010 Society of Cosmetic Chemists Lake Erie Chapter Slide 30 of 30

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

• ther techniques cannot
• Offers quantitative microscopic

measurement tool for “soft” cosmetic systems