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Quantitative Predictions of Shape-Memory Effects in Polymers.

Chris C Hornat1, Ying Yang1, Marek W Urban1

  • 1Department of Materials Science and Engineering, Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC, 29634, USA.

Advanced Materials (Deerfield Beach, Fla.)
|December 15, 2016
PubMed
Summary
This summary is machine-generated.

Polymers exhibit unique shape-memory transitions due to stored conformational entropy. This study quantifies this behavior using entropic energy density, maximum strain, and stress for materials with a glass-transition temperature and rubbery plateau.

Keywords:
dynamic and static mechanical analysisquantitative predictionsshape-memory polymers

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Area of Science:

  • Polymer Science
  • Materials Science

Background:

  • Shape-memory transitions in polymers involve directional extension and retraction.
  • These transitions are linked to stored conformational entropy.

Purpose of the Study:

  • To quantify the shape-memory effect (SME) in polymers.
  • To establish a framework for assessing SME based on fundamental thermodynamic principles.

Main Methods:

  • Quantification of stored entropic energy density (ΔSS).
  • Measurement of maximum strain (εmax) and stress (σSF) at maximum strain.
  • Application of the concept to materials exhibiting a glass-transition temperature (Tg) and rubbery plateau.

Main Results:

  • Developed a quantitative method to assess the shape-memory effect.
  • Demonstrated the relationship between stored entropy and shape-memory behavior.
  • Identified key parameters: entropic energy density, maximum strain, and stress.

Conclusions:

  • Stored conformational entropy is the key driver of unique shape-memory transitions in polymers.
  • The developed quantitative assessment is applicable to a broad range of polymers with specific thermal properties (Tg and rubbery plateau).
  • This framework enables precise evaluation and design of shape-memory polymer applications.