TY - JOUR A1 - Ecker, Melanie A1 - Pretsch, Thorsten T1 - Multifunctional poly(ester urethane) laminates with encoded information JF - RSC Advances N2 - Solvent-cast films from shape memory poly(ester urethane) (PEU) containing different weight contents of microencapsulated thermochromic pigments (T-PIGs) were prepared by drying in air. Spectrophotometric investigations unveiled that gradual loading with T-PIG black resulted in continuous darkening of the films up to filler contents of 20 wt%, accompanied by a steady enhancement of thermochromic properties. Taking this composition as standard, PEU films equipped with T-PIG black, blue and red were deposited atop PEU plaques to obtain laminate structures. Herein, the cover layer thickness (100 ± 5 µm) and the good dispersion of T-PIGs inside the polymer matrix were verified by scanning electron microscopy. Machine-readable information carriers were prepared by laser engraving quick response (QR) codes into the cover layer of the laminates and subsequently cutting cuboidal samples therefrom. Finally, thermo-mechanical programming of the QR code carriers was applied to randomly distort the code patterns, thus rendering them unreadable. Upon heating, surface decolorization and shape recovering occurred; during the ensuing cooling, the surface color and contrast reappeared whereupon the QR codes could be read out. Spectrophotometric, calorimetric and thermo-mechanical investigations gave evidence that the color switching temperature of the T-PIGs roughly coincided with the melting temperature of the ester-based switching segment and thus with the activation temperature of the shape memory effect. Apart from that unique functionality, manifold design concepts may render information carriers difficult-to-copy. Therefore, we anticipate tremendous potential as anti-counterfeiting technology. KW - Stimuli-responsive polymer KW - Shape memory polymer KW - Poly(ester urethane) KW - Microencapsulated KW - Thermochromic pigments KW - Thermo-responsive KW - Thermochromic KW - Shape memory effect KW - Polymer bilayer structure KW - Polymer laminate KW - Paste KW - Gluing KW - Spectrophotometric investigations KW - Calorimetric studies KW - Thermo-mechanical investigations KW - Information carrier KW - Anti-counterfeiting technology KW - Difficult-to-copy PY - 2014 DO - https://doi.org/10.1039/c3ra45651j SN - 2046-2069 VL - 4 IS - 1 SP - 286 EP - 292 PB - RSC Publishing CY - London AN - OPUS4-29652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -