| 摘要 |
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 Ttrans,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) and shape B is the shape at Tlow and lies geometrically between shape A and the shape of deformation of step (b). |
| 申请人 |
HELMHOLTZ-ZENTRUM GEESTHACHT ZENTRUM FÜR MATERIAL- UND KÜSTENFORSCHUNG GMBH |
发明人 |
LENDLEIN, ANDREAS;BEHL, MARC;KRATZ, KARL;CHAGANTI, SRINIVASA REDDY;NÖCHEL, ULRICH;SAUTER, TILMAN |
