Helmholtz-zentrum Geesthacht Zentrum Fuer Material- Und Kuestenforschung Gmbh

Srinivasa Reddy Chaganti

Andreas Lendlein

Karl Kratz

Marc Behl

Tilman Sauter

Ulrich Noechel

Joerg Zotzmann

The present invention relates to an article consisting of or comprising a bidirectional shape-memory polymer (bSMP), the bSMP comprising: first phase-segregated domains (AD) having a first transition temperature (T) corresponding to a crystallization transition or glass transition of the first domains (AD), second phase-segregated domains (SD) having a second transition temperature (T) corresponding to a crystallization transition or glass transition of the second domains (SD), the second transition temperature (T) being higher than the first transition temperature (T), and covalent or physical bonds cross-linking the polymer chains of the bSMP, and in this way interconnecting the first and second domains (AD, SD), wherein the second phase-separated domains (SD) form a skeleton which is at least partially embedded in the first phase-segregated domains (AD), and wherein polymer chain segments of the bSMP forming the first domains (AD) are substantially orientated in a common direction, such that the bSMP is able to undergo a reversible shape-shift between a first shape (A) at a first temperature (T) and a second shape (B) at a second temperature (T) upon variation of temperature between the first and second temperature (T, T) driven by the crystallization and melting or vitrification and melting of the first phase-separated domains (AD) and without application of an external stress, with T&#x3c;T&#x3c;T&#x3c;T.

Bidirectional shape-memory polymer, method of its production and its use

The present invention is directed to a method of preparing an actuator capable of being repeatedly and reversibly shifted between two freestanding shapes (A, B) under stress-free conditions upon varying a temperature between a temperature Tand a temperature T. The method comprising the steps:

Method of preparing a bidirectional shape-memory actuator and method of its use

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County Kildare, Ireland

Srinivasa Reddy Chaganti