Key Laboratory of Large-Format Battery Materials and Systems of the Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, P R China.
Langmuir. 2013 Jul 16;29(28):8825-34. doi: 10.1021/la401540s. Epub 2013 Jul 1.
Hydrogel photonic crystal microparticles (HPCMs) with inverse-opal structure are generated through a combination of microfluidic and templating technique. Temperature and pH responsive HPCMs have firstly been prepared by copolymerizing functional monomers, for example, N-isopropylacrylamide (NIPAm) and methacrylic acid (MAA). HPCMs not only show tunable color variation almost covering the entire wavelength of visible light (above 150 nm of stop-band shift) by simply tailoring temperature or pH value of the solution, but also display rapid response (less than 1 min) due to the small volume and well-ordered porous structure. Importantly, the temperature sensing window of the HPCMs can be enlarged by controlling the transition temperature of the hydrogel matrix, and the HPCMs also exhibit good reversibility and reproducibility for pH response. Moreover, functional species or particles (such as azobenzene derivative or magnetic nanoparticles) can be further introduced into the hydrogel matrix by using post-treatment process. These functionalized HPCMs can respond to the UV/visible light without significantly influencing the temperature and pH response, and thus, multiresponsive capability within one single particle can be realized. The presence of magnetic nanoparticles may facilitate secondary assembly, which has potential applications in advanced optical devices.
水凝胶光子晶体微球(HPCMs)具有反蛋白石结构,是通过微流控和模板技术的结合产生的。首先通过共聚功能单体,例如 N-异丙基丙烯酰胺(NIPAm)和甲基丙烯酸(MAA),制备出对温度和 pH 有响应的 HPCMs。HPCMs 不仅可以通过简单地调整溶液的温度或 pH 值来实现几乎覆盖整个可见光波长(超过 150nm 的停带位移)的可调谐颜色变化,而且由于其体积小且有序多孔结构,还具有快速响应(小于 1 分钟)的特点。重要的是,可以通过控制水凝胶基质的转变温度来扩大 HPCMs 的温度感应窗口,并且 HPCMs 对 pH 响应也表现出良好的可逆性和重现性。此外,可以通过后处理过程将功能性物质或颗粒(如偶氮苯衍生物或磁性纳米颗粒)进一步引入到水凝胶基质中。这些功能化的 HPCMs 可以对紫外/可见光产生响应,而不会显著影响温度和 pH 响应,从而可以在单个颗粒内实现多响应能力。磁性纳米颗粒的存在可能有助于二次组装,这在先进的光学器件中有潜在的应用。