Vapor-Triggered Mechanical Actuation in Polymer Composite Films Based on Crystalline Organic Cages

by Alimi, L.O., Fang, F., Moosa, B., Ding, Y., Khashab, N. M.
Year: 2022 DOI: 10.1002/anie.202212596

Bibliography

138. Alimi, L.O.; Fang, F.; Moosa, B.; Ding, Y.; Khashab, N..M., Vapor-Triggered Mechanical Actuation in Polymer Composite Films Based on Crystalline Organic Cages. Angew. Chem. Int. Ed. 2022

Abstract

The fabrication of smart materials, which can efficiently mimic biological systems through the introduction of soft components, is of great importance in the emerging fields of sensors and actuators. However, fabricating soft and stimuli responsive materials with a defined mechanism to tune and precisely control the triggered response has been considerably challenging. Herein, a smart composite film that can mechanically respond to vapors trigger then readily restores its original shape upon the removal of the stimuli is reported. This actuating composite film was prepared by mixing the highly elastic poly (vinylidene fluoride) ( PVDF ) polymer with the flexible and crystalline organic cages ( Oba-cage ) at variable concentrations. The mechanism of the mechanical response could be accurately recorded due to the ordered cage crystals. Interestingly, 50 wt% of the Oba-cage in the polymer matrix (i. e. 1:1 weight ratio) shows a very fast and reversible vapor triggered stretching and bending in less than 2 seconds. The adsorption and desorption of the organic vapors (tetrahydropyran, tetrahydrofuran, dioxane, and ethyl acetate) by the Oba-cage_50@PVDF film can be repeated many times with no noticeable loss in performance. This work highlights the importance of designing smart materials at the molecular level to precisely control the response or reaction upon the introduction of different triggers, which can ultimately lead to a monumental leap in the field of soft robotics.