The presentation deals with a basic overview regarding the Theory, Properties and Applications of Shape-memory Polymers (SMPs). It also discusses concepts such as Shape memory effect, Programming of Polymers and Practical applications of SMPs.

1. Properties and applications of
Shape Memory Polymers
Nithin Thomas
apl. Prof. Dr. Fathollah Varnik,
M.Sc. Elias Mahmoudinezhad Zirdehi
Interdisciplinary Centre for Advanced Materials Simulation (ICAMS)
Ruhr-University Bochum, Germany
nithin.thomas@rub.de
Bochum 23/01/2020

2. 2
Contents
• What are SMPs?
• Shape Memory Effect
• Classification of SMPs
• Design and Mechanism of SMPs
• Types of Shape Memory Cycles
• Comparison between SMPs and SMAs
• Applications of SMPs
• Conclusion
Original Shape Temporary Shape Recovered Shape

3. 3
What are Shape Memory Polymers (SMPs)?
• Polymeric smart materials capable of recovering from a
deformed (temporary) shape to a memorized (original) shape
when triggered by an external stimulus.
Original Shape Temporary Shape Recovered Shape
Thermally induced Shape Memory Effect in ethylene-vinyl acetate
“Mechanisms of the Shape Memory Effect in Polymeric Materials” Xuelian Wu et al. (2013)

4. 4
Shape Memory Effect
Shape memory effect (SME) and Shape Change Effect (SCE)
“Shape Memory Effect in Polymeric Materials: Mechanisms and Optimization” Ye Zhou et al. (2015)
• The property by which materials that can ‘remember’ what
shape they were and return to that shape when some stimulus
like heat or light, is applied.
A → Temporary State
B → Permanent State
H → Energy Barrier

5. 5
Shape Memory Effect
Response to stimulus of touch in Mimosa Pudica
Video by Akshay Marathe, India (2011)
Stimulus : a thing that arouses activity or energy in someone or
something; a spur or incentive.

6. 6
Shape Memory Polymers : Classification
Based on the type of Stimuli induced, SMPs are primarily classified into:
• Temperature (Thermo-responsive)
• Chemicals (Chemo-responsive)
• Light (Photo-responsive)
• Mechanical force (Mechano-responsive)

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Design and Mechanism of SMPs
The Shape Memory Cycle consists of 3 Steps
• Programming
• Storage
• Recovery

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Design and Mechanism of SMPs
Heat > Tg Apply force
Cool Remove Force
Reheat
Programming
Recovery
Storage
Repeat
Shape memory Cycle

9. 9
Design and Mechanism of SMPs
Shape Memory Cycle
“Shape Memory Polymers”, Ledlein and Kelch. Angew. 2018

10. 10
Types of Shape Memory Cycles

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Types of Shape Memory Cycles
Two-Way Shape Memory Effect exhibited by Liquid Crystal Elastomer(LCE)
Video by Christopher Yackacki, “Characterization of Active Shape-Memory Polymers” (2017)

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Comparison between SMPs and SMAs
Comparison between SMPs and SMAs
“Shape Memory Polymers”, Nithesh D Nayak (2017)
Property SMP SMA
Density (g/m3) 0.9-1.25 6-8
Phase Transformation Glass Transition Martensitic Transition
Strain (%) Upto 400% Upto 8%
Recovery Speed (s) 1s to few min <1s
Bio compatibility and
degradability
Good Poor
Condition at high
Temperature
Soft Hard
Condition at low
Temperature
Hard Soft
Cost Cheap Expensive
Programming Easy and fast Difficult

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Applications of SMPs
• Industrial Applications
Heat Shrinking tubing
Video by Christopher Yackacki, “Characterization of Active Shape-Memory Polymers” (2017)

14. 14
Applications of SMPs
• Biomedical Applications
A smart surgical suture self-tightening at elevated temperatures
“Review of progress in shape-memory polymers”, C. Liu et al. (2007)

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Applications of SMPs
• Biomedical Applications
SMPs used in Minimum Invasive Surgery
Video by Christopher Yackacki, “Characterization of Active Shape-Memory Polymers” (2017)

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Summary
• Polymers that can recover their original shape on exposure to
an external stimuli is called SMPs.
• A distinction was made between SME and SMC.
• SMPs can be classified based on stimuli used for recovery.
• A Shape memory cycle consists of Programming, storage and
recovery.
• A comparison between SMPs and SMAs were made.
• SMPs are used in numerous applications.