Thermochromic Photonic Crystal Microspheres with Uniform Color Display and Wide Coloration Range

Abstract

Thermochromic microspheres based on poly(N‐isopropylacrylamide) attract much attention in detection and sensor due to the noticeable color response and fast response rate. However, some issues such as uneven color display and narrow coloration range still limit their practical applications. Herein, novel thermochromic microspheres with homogeneous color displays and wide thermochromic range are designed by combining the microfluidic technology with the magnetically‐induced self‐assembly technique and copolymerizing acrylamide (AM) with N‐isopropylacrylamide. The photonic crystal structure with especially even colors is fast and conveniently constructed by magnetic assembly. The addition of AM makes the microspheres more hydrophilic and thus leading to a broader coloration range. The relationship between the structural color display and both the microstructures of photonic crystals and the thermo‐responsive properties of gel matrix are elucidated. The detectable temperature of microspheres rises to as high as 60°C, and displays bright iridescent color variations from orange to blue‐violet in the heating process. Importantly, their shrinking or swelling equilibrium can be reached in 80 and 105 s. Such microspheres are successfully used to visually indicate the appropriate temperature of enzymatic reaction, and have great potential in practical applications such as visual temperature detection and efficiency monitoring of chemical reactions.

A Photonic Crystal Gel for Naked-Eye Detection of Uric Acid with High Sensitivity and Specificity

“…In recent years, more attention has been devoted to the field of colorimetric applications of PC sensors owing to their merits of nonfading, easy-to-operate, and unique optical modulation properties . PC sensors have demonstrated utility in detecting glucose, , DNA, , protein, , H 2 O 2 , , temperature, − and other signals. Since uricase can oxidize uric acid to H 2 O 2 , − it is expected that H 2 O 2 -responsive redox PC sensors will be used for uric acid detection.…”

Synthesis of Controllable Superparamagnetic Nano Fe3O4 Based on Reduction Method for Colloidal Clusters of Magnetically Responsive Photonic Crystals

“…On the other hand, superparamagnetic nano Fe 3 O 4 in biomedicine, with its stable material property and good biocompatibility, can serve as magnetic fluid assisted hyperthermia and is expected to become an effective treatment method for cancer [5,6]. Therefore, this monodisperse superparamagnetic nanoparticle is widely used in the fields of color display [7,8], anti-counterfeiting [9,10], sensors [11,12], and biomedicine [13,14].…”