Photonic Crystals For Assembling Research Under Electric Field And Ultrasonic-gravity

Photonic crystals are a type of novel materials with order structure,nanopores, channel and optical band gap.They have hence important applications in physics,chemistry,biological science and engineering fields.This paper focuses on assembling and application aspect. There have many different kinds of assembly methods, such as relying on light field, electric field, magnetic field and gravity field or interface induction, mechanical processing, etc. Choosing different methods according to various demands. Traditional photonic crystal sensor generally utilizes monodisperse particles to assemble opal or inverse opal structure,then filling the monomer polymer and developing sensor.Although photonic crystals have good property in contrast with traditional chromatography and electrochromatography in chemical separation, there still exist great challenge on how to prepare high quality photonic crystals column in short time.Therefore our objective studies assembling under electric field,ultrasonic and ultrasonic-gravity etc as follow:(1)Using particle gel or nanoparticles as a block in the end of capillary.The gel block can raise speed assembly according to experiment data, but forming a long crack in column on account of annular electroosmosis.Nanoparticles can replace gel as block to avoid crack, however this method only applies to nanoparticles below 400 nm.(2)Building three methods to assemble crystalline colloidal arrays: ultrasonic, centrifuge-ultrasonic, gravity-ultrasonic.The crystalline colloidal arrays can produce great response for copper ion and mechanical stress.Recovering to 70% reflection intensity within 25 s after removing stress.