Magnetically responsive photonic crystals (MRPCs) have the merits of high refractive index, fast and fully reversible photonic response across the visible spectrum under external magnetic field when comparing to the traditional photonic crystals composed of monodispersed SiO2 or polymer particles.1 They are promising for the fabrication of chemical or biomolecule sensors. Although they have been solidified in various responsive polymers in the forms of films or balls, the relatively high content of polymers always increases the diffusing length of analytes leading to the failure of real-time sensing. Photonic nanochains are the smallest structure of MRPCs, however, up to now, only SiO2or carbon has been used to fix the nanochains which are not suitable for sensing.2, 3 Thus, we have fixed individual photonic nanochains in responsive polymers by dispersing steric-stabilized Fe3O4@PVP particles (previously fabricated by our group4) in solutions of monomers which are subsequently polymerized under external magnetic field and UV irradiation.5 It has been found that the interparticle distance of the as-obtained responsive photonic nanochains can be responsive to external field like pH, solvents or other analytes. Most importantly, the responsive photonic crystal chains show a fast response rate when the external environment changed due to tens nanometers of responsive polymer thickness. Our result will significantly shorten the diffusion length of analytes, accelerating the response rate of photonic crystal sensors for chemical sensing or biosensing devices.

References:

1 Mingsheng Wang, Le He and Yadong Yin, Mater. Today 16 (4), 110 (2013).

2 Yongxing Hu, Le He, and Yadong Yin, Angew. Chem. Int. Ed. 50 (16), 3747 (2011).

3 Hui Wang, Qian-Wang Chen, Yi-Fei Yu and Kai Cheng, Dalton Trans. 2011, 40(18), 4810 (2011).

4 Wei Luo, Huiru Ma, Fangzhi Mou, Mingxing Zhu, Jindan Yan, Jianguo Guan,Adv. Mater. 26 (7), 1058 (2014).

5 Wei Luo, Huiru Ma, Fangzhi Mou, Lei Kong, Jianguo Guan, In Preparatioin.

Wei Luo

Oregon state university

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