Self-regenerating materials are intriguing. If critical properties of a failing material could be easily restored, this would significantly extend its life time. Functional surfaces fail due to damage or contamination. Instead of trying to make “better” surfaces, we propose to make a material that can shed its entire defective layer, like a reptile shedding its skin, and present a new one. This concept is illustrated in Fig. 1. The selective and sequen¬tial shedding of polymer layers from a multi-stack is so far an unresolved concept.
We obtained proof-of-concept for complete layer shedding from a polymer layer stack using antimicrobial polymers as a model system. We assembled a three layer system consisting of a bio¬degradable polymer interlayer sandwiched between two antimicrobial polymer layers. We showed using fluorescence microscopy, ellipso-metry, surface plasmon resonance spectroscopy, and Fourier-Transform infrared spectroscopy that this three-layer system can shed the top layer by degradation of the interlayer. Antimicrobial assays proved that the bottom layer was as active as the previous three layer stack. This demonstrated that it is feasible to retain the functionality of the emerging layer. We will further develop this concept to enable selective and sequential shedding from a multilayer stack, and transfer it to other functionalities.
Acknowledgement. Thanks to A. Al-Ahmad and D. L. Guevara-Solarte for their expert assistance with the antimicrobial assays.
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 F. Dorner; D. Boschert; A. Schneider; W. Hartleb; A. Al-Ahmad, K. Lienkamp, ACS Macro Lett. 2015, 4, 1337.