Sterically Hindered Organogels with Self-Healing, Impact Response, and High Damping Properties.

Abstract

Organogel materials are vital for impact or shock resistance because of their highly tailored dynamic properties. However, concurrently achieving excellent anti-impact and damping performances, high stability, and self-healing properties is challenging. Herein, a novel intelligent protective organogel (IPO) comprising a dynamic boronic ester containing poly(urethane-urea) as the network skeleton with a matching mesh size is synthesized, the network precisely entraps the hyperbranched fluid used as the bulky solvent via steric hindrance. The IPO exhibits self-healing ability, excellent impact responsiveness (a 1950-fold increase in flow stress under various impact speeds), and energy dissipation (the loss factor >0.8 from 10^-4  to 10⁴ Hz). The IPO maintains its dynamic mechanical properties during hot pressing and hydrolysis, exhibiting  high stability. Furthermore, the IPO exhibits omnibearing protection. When used as a protective coating, the IPO dissipates the impact force by 87% and 89% of control upon passive and active impact, respectively. When used as a shock pad, it attenuates 91% of the amplitude in the high-frequency vibrations. This study offers a novel perspective on the synthesis of tailored sterically hindered organogel and provides valuable insights into the development of next-generation intelligent protective materials that exhibit impact and vibration resistance.