Full-color mechanical sensor based on elastic nanocomposite hydrogels encapsulated three-dimensional colloidal arrays

Quan

Int. J. of Precis. Eng. and Manuf.-Green Tech.

et al. 2021

Recently, there has been much interest in applying the color changes of nano-patterned structures to sensor technology. However, the lithographic nano-patterning process is not environmentally friendly, and it is difficult to fabricate large areas of color due to limitations associated with this approach. In this study, we realized a highly tunable structural coloration based on a Fabry–Perot interferometer design that does not require nano-patterning processes. To increase the reflected color change according to the angle, a color element using an asymmetric metal–insulator–metal structure was applied, fabricated using silver–silicon dioxide–tin (Sn), respectively. Using the optical properties of Sn, we maximized the change in reflection color and realized three primary colors of subtractive color of cyan, magenta and yellow according to the angle of designed MIM structure. Theoretical and experimental results revealed that the color and intensity of the reflectance depended strongly on the angle of the reflective surfaces. The manufacturing process is simple and yields large surfaces of high quality. Based on this premise, we fabricated a soft robot capable of color camouflage, and an angle-detecting color sensor for inspecting the three-dimensional shape quality of curved glass with a high sensitivity of 1.8 nm/degree. In addition, we propose a shape evaluation method by color, spectrometry, and monochromatic light.

Section: Resultsmentioning

confidence: 99%

Lithography-free and Highly Angle Sensitive Structural Coloration Using Fabry–Perot Resonance of Tin

Quan

Int. J. of Precis. Eng. and Manuf.-Green Tech.

et al. 2021

“…Notably, the photonic skin is based on the Bragg reflection, which depends on the viewing angles. Therefore, the color responses of the photonic skin should be measured at a fixed angle for consistent strain evaluation . Viewing angle‐independent photonic architectures need to be developed for the broader applications of the wearable photonic skin .…”

Section: Resultsmentioning

confidence: 99%

Ultra‐Adaptable and Wearable Photonic Skin Based on a Shape‐Memory, Responsive Cellulose Derivative

Lee

et al. 2019

Adv Funct Materials

Photonic skins enable a direct and intuitive visualization of various physical and mechanical stimuli with eye-readable colorations by intimately laminating to target substrates. Their development is still at infancy compared to that of electronic skins. Here, an ultra-adaptable, large-area (10 × 10 cm 2 ), multipixel (14 × 14) photonic skin based on a naturally abundant and sustainable biopolymer of a shape-memory, responsive multiphase cellulose derivative is presented. The wearable, multipixel photonic skin mainly consists of a photonic sensor made of mesophase cholesteric hydroxypropyl cellulose and an ultraadaptable adhesive layer made of amorphous hydroxypropyl cellulose. It is demonstrated that with multilayered flexible architectures, the multiphase cellulose derivative-based integrated photonic skin can not only strongly couple to a wide range of biological and engineered surfaces, with a maximum of ≈180 times higher adhesion strengths compared to those of the polydimethylsiloxane adhesive, but also directly convert spatiotemporal stimuli into visible color alterations in the large-area, multipixel array. These colorations can be simply converted into 3D strain mapping data with digital camera imaging.

“…[226] Since then, the diffraction signals of CCA based on Bragg's law have been widely used in micromechanics responsive hydrogels. [227][228][229] However, limited by different principles to characterize the deformation degree, the spatial resolution of CCA-based micromechanics responsive hydrogels suffers a great loss.…”

Section: Pcca Hydrogelsmentioning

confidence: 99%

An Insight into Skeletal Networks Analysis for Smart Hydrogels

Sun

Wang

et al. 2021

Adv Funct Materials

Hydrogels are 3D cross-linked polymer networks. Benefiting from the flexible designs and reasonable constructions of these networks, a large number of smart hydrogels with response characteristics to specific stimuli have received widespread attention and developed rapidly. The skeletal networks composed of the skeletal polymer chains and effectual cross-links are the soul of such soft materials, and the response behaviors fundamentally depend on the dynamic characteristics of skeletal networks. Herein, the novel concepts of skeletal networks analysis to describe, understand, and guide the advanced designs and applications of smart hydrogels are proposed. Representative glucose-sensitive hydrogels and DNA-based smart hydrogels are reviewed to demonstrate the principle of skeletal networks analysis and clarify its practical guidance. Summarizing and classifying the characterizations and conversions of skeletal networks dynamics based on different response mechanisms provides a realistic solution. On this basis, advanced applications of smart hydrogels guided by skeletal networks dynamics including biochemical detection, cell mechanics sensing, drug delivery systems, and dynamic complex soft materials are typically reviewed. The skeletal networks analysis for smart hydrogels is of great significance for understanding the microstructures of hydrogels and guiding the designs of soft materials and their smart applications in the fields of analytical science and advanced materials.