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1. (WO2014206812) METHOD OF PREPARING A BIDIRECTIONAL SHAPE-MEMORY ACTUATOR AND METHOD OF ITS USE

Pub. No.:    WO/2014/206812    International Application No.:    PCT/EP2014/062697
Publication Date: Thu Jan 01 00:59:59 CET 2015 International Filing Date: Wed Jun 18 01:59:59 CEST 2014
IPC: B29C 61/00
B29C 61/06
Applicants: HELMHOLTZ-ZENTRUM GEESTHACHT ZENTRUM FÜR MATERIAL- UND KÜSTENFORSCHUNG
Inventors: LENDLEIN, Andreas
BEHL, Marc
KRATZ, Karl
CHAGANTI, Srinivasa Reddy
NÖCHEL, Ulrich
SAUTER, Tilman
Title: METHOD OF PREPARING A BIDIRECTIONAL SHAPE-MEMORY ACTUATOR AND METHOD OF ITS USE
Abstract:
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 Tlow and a temperature Tsep. The method comprising the steps: (a) providing an actuator consisting of or comprising a covalently or physically cross-linked polymer network, the polymer comprising a first phase having a thermodynamic phase transition extending in a temperature range from Ttrans,onset to Ttrans,offset, and an elastic phase having a glass transition temperature Tg, with Tg < Ttrans,onset, the polymer having an initial shape; (b) deforming the polymer to a deformation shape at a temperature Tprog by applying a stress, where the deformation is adapted to align chain segments of the polymer; (c) setting the polymer to a temperature Tlow with Tlow < Ttrans,onset under maintaining the stress as to provide a solidified state of the polymer domains associated with the first phase; (d) heating the polymer to a predetermined separation temperature Tsep, with Ttrans,onset < Tsep< Ttrans,offset, under stress-free conditions as to melt first polymeric domains (AD) of the first phase having a transition temperature in the range between Ttrans,onset and Tsep and to maintain second domains (SD) of the first phase having a transition temperature in the range between Tsep and Τtrans,offset in the solidified state, thus implementing shape A, where shape A geometrically lies between the initial shape provided in step (a) and the deformation shape applied in step (b).