Feel the Power of Force: From Polymer Mechanochemistry to Mechanically Responsive Soft Materials

Mechanical force is an essential tool to keep our physical world running by modulating the conversion of mechanical energy into other forms of energy, such as thermal, photonic, and chemical energies. Over the past decade, mechanical force has become a powerful tool for chemists to create colors, induce reactions, and develop advanced manufacturing techniques. However, fundamental studies on the interactions and propagations of forces in soft materials still face significant challenges. A well-developed design strategy for mechanoresponsive soft materials is also in high demand. In this seminar, I will select polymer mechanochemistry and microencapsulation as micro- and mesoscale strategies to design mechanoresponsive materials, respectively. Mechanochemistry refers to chemical processes induced by mechanical force. Mechanically sensitive molecules, called mechanophores, can undergo chemical transformations when appropriate mechanical force is applied. Mechanochemistry provides an emerging tool for high-resolution mechanical sensing applications, such as stress mapping, advanced ultrasound imaging, and damage detection. Microcapsule-based polymer composites have been extensively used in mesoscale controlled-release applications. Several recent advances in microcapsules will be discussed, including microscale damage detection, cure-on-demand materials, and self-healing polymer composites. Mechanoresponsive polymeric materials with multiscale responsive mechanisms provide a promising solution to address challenges in mechanical sensing and fabrication techniques. Research and engineering perspectives of mechanoresponsive soft materials will also be discussed.