Dispersion

Nanoparticle dispersion may not be as important for effective actuation as

previously thought

Almost the entire range of visible light is absorbed by the wide range of particle

sizes

This makes dispersion of specific sized particles less important

oSmaller particles (10 nm ≤ d ≤ 40 nm) may have agglomerated

Material Considerations

PEG is a plasticizer which softened the sample

oDid not hold the deformed state causing a large start angle

oHigher initial angular velocity

oLowest final angle

Physical Mix has no PEO carrier polymer

oHighest amount of SMP (engine for actuation)

oAg NPs are not clumped in PEO segments therefore are more evenly

distributed

Future Work

Cheaper materials • Uniform sized particles • Various types of carrier polymers •

Temperature differences over time • Actuation of different shapes

Laser Activated Shape Memory Polymer Nathan Klimek, Jake LaRoe, and Jackson Parker 4/23/2014

TE Senior Design 2013-2014

Introduction

Background

Experimental Procedure Sponsorship & Acknowledgements

Senior Design Faculty Mentors: Dr. Russell Gorga , Dr. Jesse Jur, & Dr. Jon Rust

Sponsored by Dr. Russell Gorga (Department of Textile Engineering, Chemistry, and Science) in partnership with Dr. Laura Clarke, Dr. Jason Bochinski (Department of Physics)

This work is supported by NSF CMMI-0829379

Special Thanks To: David Abbott, Colin Curtis, and Swapnil Landge

http://en.wikibooks.org/wiki/A-level_Physics_(Advancing_Physics)/Resonance http://www.extremetech.com/extreme/147656-worlds-first-digital-laser-shapes-its-own-beam-heralds-new-age-of-trippy-concert-lighting http://www.compositesworld.com/news/nanocomposite-technology-nears-commercialization

Conclusions

Analysis Project Description Evaluate methods of incorporating silver nanoparticles into Shape Memory Polymer (SMP) to achieve effective shape change via laser light

How Observing the behavior of folded thin-film rectangular samples of SMP under intense laser light

Sponsor Constraints • Silver nanopowder

o Large range of sizes (10-100nm) • 445 nm (wavelength) Class IV Laser

Carrier Polymer

Physical Mix Shape Memory Polymer

Key Comparisons Dispersion

Actuation

Metrics for Success Compete with, or beat conventionally heated samples on: • Ease of fabrication • Effectiveness of actuation • Cost of production

ΔHeat

Metric SMP (Control) Conventional Heating

Physical Mix Carrier EDTA PEG

Starting Angle 34.5o ± 9.4o 43.5o ± 8.5o 38. 1o ± 4.4o 36.6o ± 5.5o 68.7o ± 5.9o

Stopping Angle 175.6o ± 1.9o 177.9o ± 1.9o 172.7o ± 4.4o 173.9o ± 4.5o 171.8o ± 5.5o

Warm Up Time* (Seconds)

0.48 ± 0.35 2.59 ± 0.94 2.48 ± 0.68 2.48 ± 0.67 1.52 ± 0.25

Time To Completion (Seconds)

21.4 ± 4.7 19.4 ± 3.2 26.6 ± 5.6 27.9 ± 6.3 22.6 ± 3.2

Cost Per 5g Sample Batch

$0.01 $0.59 $1.68 $1.68 $1.73

Manufacturing Time

~1 hour ~1 hour ~48 hours ~48 hours ~48 hours

Graphs are based on a 255 point gray scale. 255 is perfectly black and 0 is

perfectly white

What Do These Graphs Mean? The flatness of the graph shows color consistency of a sample.

SMP is the most uniform because it has no dark Ag NPs in it. The Physical Mix has spikes where the Ag NPs agglomerate. Carrier Polymer is the most uneven because the Ag NPs are only in the

carrier segments, causing overall poor dispersion throughout the SMP.

• Conventional Heating (Control) —The actuation of 100% SMP samples with no Ag NPs present. Heat supplied via a conventional oven at 70oC.

• Compare to 4 new methods o Physical Mix —simply mixing nanopowder with SMP powder o Carrier Polymer —mixing sonicated Ag NPs into dissolved PEO, then

grinding PEO and SMP o PEG Stabilized —stabilizing the Ag NPs in suspension with polyethlyene

glycol o EDTA Stabilized —stabilizing Ag NPs with ethylenediaminetetraacetic

acid, a common chelating agent.

Motivation Advantages of photothermal heating • Localized heating • Remote actuation • Self healing materials • Responsive materials

0

5

10

15

20

25

0 10 20 30 40

De

gre

es/

Seco

nd

Seconds

Figure 2: Angular velocity of different dispersion methods over time

PM

Carrier

PEG

EDTA

Conv

0

20

40

60

80

100

120

140

160

180

0 10 20 30 40

De

gre

es

Seconds Figure 1: Actuation angle of different dispersion methods over time

PM

Carrier

PEG

EDTA

Conv

Figure 1 Breakdown

• Note the pronounced warm

up time (flat region at t=0) in all of the laser actuated samples

• Physical Mix has the fastest and most complete actuation

• Starting angle of PEG is the highest then slows down rapidly

• This data comes from the average of 10 trials per method

Figure 2 Breakdown

• In general, maximum

velocity is observed around 6 seconds

• Carrier and EDTA have low maximum velocities, but they sustain their velocities longer

• Physical Mix has the highest angular velocity of all the samples

http://galleryplus.ebayimg.com/ws/web/180781956607_1_0_1/1000x1000.jpg

Shape Memory

Polymer - A polymer that can

be ‘set’ to a certain shape (the

ground shape), deformed, and then with the application of

energy, return to the set state

Dispersion - How one substance is spread throughout another

Photothermal Heating – The heating of a substance by photonic energy. The energy provided by the photons vibrate the particles (internal energy) and the system heats up.

Laser - Light Amplification by Stimulated Emission of Radiation. Lasers emit light coherently in order to allow the photons to be focused on a tight spot.

Resonant Frequency – Frequency at which the system oscillation amplitude is the greatest.

Grind Stabilize Melt Laze Analyze

* Warm up time: Time until ω ≥ 4 o/seconds

1 mm 1 mm 1 mm