Bioinspired Thermoresponsive Photonic Polymers with Hierarchical Structures and Their Unique Properties

Abstract

Thermoresponsive photonic materials having hierarchical structures are created by combining a template of Morpho butterfly wings with poly(N-isopropylacrylamide) (PNIPAM) through a chemical bonding and polymerization route. These materials show temperature-induced color tunability. Through reacting with both NIPAM monomers and the amino groups of chitosan in wing scales, glutaraldehyde workes as a bridge by creating chemical bonding between the biotemplate and the PNIPAM. The corresponding reflection peaks red-shift with increase in temperature-an opposite phenomenon to previous studies, demonstrating a thermoresponsive photonic property. This unique phenomenon is caused by the refractive index change due to the volume change of PNIPAM during the temperature rising. This work sets up an efficient strategy for the fabrication of stimuli-responsive photonic materials with hierarchical structures toward extensive applications in science and technology.

Multifunctional Hydrogels with Temperature, Ion, and Magnetocaloric Stimuli‐Responsive Performances

“…Moreover, the color is uniform on the surface of the hydrogel under all experimental temperatures. Notably, the shift of diffraction wavelength can be attributed to the decrease of the lattice spacing in the 1D chain structure, which is further owing to the heat‐induced collapse of hydrogel matrix . When the incident light is parallel to the normal direction of the photonic hydrogel, the diffraction wavelength ( λ ) can be calculated by Equation where n eff is the effective refractive index of the photonic hydrogel, and d is the lattice spacing.…”

“…Similar to living organisms with responses to the surrounding environments, responsive polymers demonstrate reversible variation under external stimuli, including temperature, pH, ions, forces, and electric field, etc . Recently, the creation of responsive photonic hydrogels (RPHs) has aroused particular interest since photonic materials, consisting of two different dielectric materials arranged periodically in one or more dimensions, can offer an opportunity for controlling the transmission of light . In the process of analyte detection, RPHs can not only control or detect photons by their ordered structures but also can change propagation of photons in the response to environmental changes.…”

Toward the Burgeoning Optical Sensors with Ultra‐Precision Hierarchical Structures Inspired by Butterflies

“…reported a thermoresponsive stimulus tunable photonic structure by assembling smart polymers into butterfly wings photonic architecture. They used chemical bonding and polymerization method to combine Morpho butterfly wings with PNIPAM [ 40 ] ( Figure ). When the temperature goes up, the volume of PNIPAM is changed that causes a detectable reversible change in the refractive index.…”

Recent biomedical applications of bio-sourced materials

“…Thus, natural hierarchical photonic structures have been used to fabricate various sensors, such as thermoresponsive sensors [39,40]. Xu et al reported a simple method for producing an intelligent sensor that exhibited high performance and tunable color as the temperature changed (Fig.…”