Sci. Adv. Today 1 (2015) 25223  
  Review Article  
Soft photonic crystals based on polymer microgels  
  Tian Zhang and Jintao Zhu  
Key Laboratory of Materials Chemistry for Energy Conversion and Storage of the Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  Microgels are three-dimensional (3D) crosslinked polymer network, which has strong water absorption ability, flexibility, responsiveness and good biocompatibility. Due to the inherent special properties of the microgels, it is widely used to create responsive soft photonic crystals (PCs). This review article describes the use of microgels as soft nanobuilding blocks for the generation of responsive PCs through the self-assembly strategy. These optical hydrogels consist of periodic microgels with photonic band gap and demonstrate brilliant structural color. The structural color of the photonic materials provides a simple detection means and can be visually identified by the naked eyes, potentially useful in the areas of display, detection, diagnostics, sensing and others. We briefly introduced the synthesis of the monodispersed polymer microgels. Formation of the film/bulk soft PCs and spherical three dimensional (3D) PCs based on the soft building blocks are then discussed. Among which, fabrication of 3D spherical PCs microbeads based on the polymer microgels through microfluidic technique will be focused in this paper. We will also discuss the advantages of the microgels-based soft PCs compared to the traditional hard nanoparticles. The potential applications of the soft responsive PCs are provided, followed by the summary and perspective of this emerging research field.  
  Cite this article as:  
  Tian Zhang and Jintao Zhu, Soft photonic crystals based on polymer microgels , Sci. Adv. Today 1 (2015) 25223.