Filtern
Erscheinungsjahr
- 2014 (2)
Dokumenttyp
Sprache
- Englisch (2) (entfernen)
Schlagworte
- Anti-counterfeiting (2) (entfernen)
The selective compression of quick response (QR) and Data Matrix code carriers based on shape memory polymer (SMP) with a freely configurable steel ball type indenter and adjacent thermo-mechanical shape fixing gave notched, room temperature (23 °C) stable, temporary shapes with non-decipherable codes. The microscopic investigation of cryomicrotome sections unveiled indentation-related shape fixities of about 90 %. Independent of the selected two-dimensional code, the triggering of the SM effect resulted in sufficient shape recoveries to restore the code readability so that a maximum number of characters including 122 for a QR code (version 7) and 112 in case of a Data Matrix code (version 12) could be read with a scanning and decoding device. Due to the large number of difficult to copy shapes with on demand releasable information, SMPs may serve as viable information carriers for product and brand protection applications.
Two design approaches for multifunctional information carriers are introduced. In the first one, quick response (QR) code carriers, which were composed of poly(ester urethane) (PEU) and microencapsulated thermochromic pigments (T-PIGs), differing in color and color switching temperature (CST), were prepared. The obtained material systems exhibited machine-readable QR codes at 23 °C and a two-stage decolorization when heated, culminating in unreadable QR codes at temperatures above the highest CST of the employed T-PIGs. In the second scenario, information carriers were sealed with a dark, thermochromic PEU layer. As a result, the QR codes were hidden at 23 °C and became readable upon heating due to color fading. Beyond the characterization of the employed components, preparation methods, functionality analyses and durability investigations are reported. When heated after thermo-mechanical programming, pronounced shape memory properties could be verified. The thermo-responsiveness of such multifunctional material systems may qualify them for usage in anti-counterfeiting applications.