1. INVESTIGATION OF SELF-HEALING
COPOLYMERS UTILIZING TIME
DEPENDENT RESONANT
SPECTROSCOPY
Nicholas R. Bowers, Physics Major
Kenneth A. Pestka II,Assistant Professor
Joseph N. Kistner, Physics Major
Rollins College
!
Stephen J. Kalista Jr.
Union College

2. • Idea. Explore self-healing behavior of
copolymers by analyzing changes in
their acoustic properties over time
• Goal. Determine healing timeframe for
different copolymers to identify factors
that may influence the healing process
PURPOSE OF INVESTIGATION

3. • Triggered by sufficient energy transfer
• Three proposed phases of healing
• Instantaneous elastic molten state
• Welding and sealing
• Solid polymer interdiffusion and realignment
• Compositional variation, damage amount and mechanism, and sample age
and deterioration may all influence the healing action of these polymers
[1] S. J. Kalista,T. C.Ward,“Thermal characteristics of the self-healing response in poly (ethylene-co-methacrylic acid) copolymers”,
Journal of the Royal Society Interface. (2006).
Adapted from [1].
SELF-HEALING BEHAVIOR OF
COPOLYMERS

4. SELF-HEALING COPOLYMERS
• Poly (ethylene-co-methacrylic
acid) copolymers (EMAA
copolymers)
• Four different materials
developed by DuPont which
differ in molecular weight,
ionic content, and material age

5. SELF-HEALING COPOLYMERS

6. SELF-HEALING COPOLYMERS
Nucrel (Non-ionic) Suryln (Ionic)
Greater
Molecular Weight
Lesser
Molecular Weight
60% of Acid Groups
Neutralized by Na
30% of Acid Groups
Neutralized by Na

7. • Prepared samples
• Damaged samples
• Placed samples in scanning
cell
• Scanned samples continuously
over several hours
SELF-HEALING COPOLYMERS

8. • Resonance spectrum depends on microscopic
structure and sample geometry
• Microscopic structure evolves throughout the
healing process
• Expect changes in the resonance spectrum
during healing process
• Analyze trends in the time evolution of the
spectrum to quantify healing mechanism
ACOUSTIC AND ULTRASONIC
TIME DEPENDENT RESONANT
SPECTROSCOPY (TDRS)

9. • Resonance spectrum depends on microscopic
structure and sample geometry
• Microscopic structure evolves throughout the
healing process
• Expect changes in the resonance spectrum
during healing process
• Analyze trends in the time evolution of the
spectrum to quantify healing mechanism
ACOUSTIC AND ULTRASONIC
TIME DEPENDENT RESONANT
SPECTROSCOPY (TDRS)

10. • Resonance spectrum depends on microscopic
structure and sample geometry
• Microscopic structure evolves throughout the
healing process
• Expect changes in the resonance spectrum
during healing process
• Analyze trends in the time evolution of the
spectrum to quantify healing mechanism
ACOUSTIC AND ULTRASONIC
TIME DEPENDENT RESONANT
SPECTROSCOPY (TDRS)

11. • Resonance spectrum depends on microscopic
structure and sample geometry
• Microscopic structure evolves throughout the
healing process
• Expect changes in the resonance spectrum
during healing process
• Analyze trends in the time evolution of the
spectrum to quantify healing mechanism
ACOUSTIC AND ULTRASONIC
TIME DEPENDENT RESONANT
SPECTROSCOPY (TDRS)

12. EVOLUTION OF RESONANCE PEAKS DURING HEALING
Overlapping
Resonance Peaks
Nucrel 960
8x8mm Sample
Damaged by Nail

13. 0.000#
0.020#
0.040#
0.060#
0.080#
0.100#
0.120#
0.140#
0.160#
545# 550# 555# 560# 565# 570# 575# 580# 585# 590# 595#
Energy#(Rela6ve)#
Frequency#(kHz)#
#t=0h# #t=0.35h# #t=10.3h#
EVOLUTION OF RESONANCE PEAKS DURING HEALING
Nucrel 960
8x8mm Sample
Damaged by Nail

14. QUALITY FACTORS OF RESONANCE PEAKS
Nucrel 960
8x8mm Sample
Damaged by Nail

15. 0"
50"
100"
150"
200"
250"
300"
0" 1" 2" 3" 4" 5" 6" 7" 8" 9"
Quality"Factors"
Time"(Hours)"
"563kHz" "572kHz" "580kHz"
EVOLUTION OF QUALITY FACTORS DURING HEALING
Nucrel 960
8x8mm Sample
Damaged by Nail

16. 0"
50"
100"
150"
200"
250"
300"
0" 1" 2" 3" 4" 5" 6" 7" 8" 9"
Quality"Factors"
Time"(Hours)"
"563kHz" "572kHz" "580kHz"
EVOLUTION OF QUALITY FACTORS DURING HEALING
Nucrel 960
8x8mm Sample
Damaged by Nail
Phase 3

17. 0.0# 0.5# 1.0# 1.5# 2.0# 2.5# 3.0# 3.5# 4.0# 4.5# 5.0# 5.5# 6.0# 6.5# 7.0# 7.5# 8.0# 8.5# 9.0# 9.5# 10.0#
Phase#2#Phase#3#
Time#(Hours)#
925# 960# 8920# 8940#
PRELIMINARY HEALINGTIMEFRAMES
Greater Molecular Weight
Lesser Molecular Weight
Higher Ion Content
Lower Ion Content
925
960
8920
8940

18. PRELIMINARY RESULTS
AND SUMMARY
• Preliminary results
• Establish healing timeframe estimates for four EMAA copolymers
• ConfirmTDRS is a useful tool for determining healing timeframe
• Are consistent with the three-phase healing model
• Correlation between material composition and healing timeframe
• Correlations between healing timeframes and sample age, size, and
damage amount are being explored

19. ACKNOWLEDGEMENTS
• Rollins College Student-Faculty Collaborative
Scholarship Program
• DuPont