Self-strengthening polymer composites by vibration
November 10-14, 2019
Materials in everyday use are subjected various conditions, temperature, humidity and more particularly mechanical vibration. Though rational designs have been made to withstand these environmental effects, materials still become weaker overtime under cyclic loading. In nature, bone cells can adapt to cyclic loading via adding bone accordingly, a process called bone remodeling. This endows bone the ability to strengthen when subjected to stresses thereby preventing structural damage and improving the mechanical strengthen. Inspired by this, we have previously demonstrated the strengthening of material by ultrasound triggered polymerization and polymer crosslinking but lack adaptive nature to different loadings, particularly for the low frequency vibration (<20kHz) that material usually suffered. Herein, we describe a bone-remodeling-mimic strategy to harnessing low frequency vibration energy (500-5000Hz) and use for strengthening material. We used piezoelectric ZnO nanoparticle to mechanochemically initiate thiol-ene “click” reaction in an organogel system. The organogel can sense and adapt accordingly to the input vibrational energy, in terms of power, time and frequency, showing a maximum 60 times increase in modulus. Moreover, the degree of adaption can be monitored and self-reported to external electronics driven by its change in modulus. This integration of programable feature enables the precise control of material’s property for a wide range of applications.
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Aaron Esser-Kahn, Zhao Wang, and Jun Wang, "Self-strengthening polymer composites by vibration" in "Composites at Lake Louise 2019", John Kieffer, University of Michigan, USA Erik Spoeke, Sandia National Laboratories, USA Meisha Shofner, Georgia Institution of Technology, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/composites_all_2019/17