Smart Silk Origami as Eco-sensors for Environmental Pollution

Abstract

Origami folding is an easy, cost-effective, and scalable fabrication method for changing a flat material into a complex 3D functional shape. Here, we created semicrystalline silk films doped with iron oxide particles by mold casting and annealing. The flat silk films could be loaded with natural dyes and folded into 3D geometries using origami principles following plasticization. They performed locomotion under a magnetic field, were reusable, and displayed colorimetric stability. The critical parameters for the design of the semi-autonomous silk film, including ease of folding, shape preservation, and locomotion in the presence of a magnetic field, were characterized, and pH detection was achieved by eye and by digital image colorimetry with a response time below 1 min. We demonstrate a practical application—a battery-free origami silk boat—as a colorimetric sensor for waterborne pollutants, which was reusable at least five times. This work introduces silk eco-sensors and merges responsive actuation and origami techniques.

Green, Low‐carbon Silk‐based Materials in Water Treatment: Current State and Future Trends

“…SBMs also enable the preparation of pH detection sensors that are flexible and foldable. Matthew et al [124] . prepared foldable silk films through a process involving mold casting, annealing, and plasticizing (Figure 12e).…”

“…SBMs also enable the preparation of pH detection sensors that are flexible and foldable. Matthew et al [124] prepared foldable silk films through a process involving mold casting, annealing, and plasticizing (Figure 12e). These silk films could be loaded with natural dyes such as curcumin and anthocyanin, exhibiting distinct color changes in response to changes in pH levels, with detection possible within a minute.…”

“…(d) Real sample analysis of water samples [121] . (e) Sensing capability of silk films [124] . Copyright (2022), with permission from the American Chemical Society.…”

Deployable linear and spiral array structures based on a Kresling-inspired mechanism with integrated scissor arms

“…Spatial structures inspired from origami have broad applications in the fields of science and engineering because they are complex three-dimensional (3D) structures that are highly portable, reconfigurable, and deployable. These applications include solar arrays (Cai et al, 2021;Karmakar and Mishra, 2022;Li et al, 2022), robotic devices (Chen et al, 2022;Fonseca and Savi, 2020;Robertson et al, 2021;Yang et al, 2021), antennas (Georgakopoulos et al, 2021;Ha et al, 2022;Huang et al, 2022;Zhang et al, 2020), medical devices (Kim et al, 2021(Kim et al, , 2022Li et al, 2019;Zhao et al, 2022), and sensor technology to monitor pollution (Matthew et al, 2022).…”