Fabrication Of Structured Color Microspheres With Electrochemical Responsiveness By Microfluidic

In recent years,with the development of the potential applications of photonic crystal materials in coding,sensing and display,the research about the functional photonic crystal materials and the apllication of their bright colors have been the concerns of researchers.Colloidal crystals are monodisperse three-dimensional ordered structures made up by the inorganic or organic nanoparticles,which are an important branch of photonic crystal materials.The photonic crystal prepared by the assembly of the colloidal crystal can result in Bragg diffraction,by adjusting the size of the assembled nanoparticles,and that is the reason of the structure colour.In addition to these colour characteristics,colloidal crystal has shown great potential in catalysis,medicine,filtration,adsorption,and so on.Because self-assembled colloidal crystals can be used as a template to prepared the three-dimensional ordered pore structure made of hydrogel,which is widely used for coding,sensing,display and other aspects of researches.However,as most of the recent colloidal crystal particles were composed of silica or polystyrene nanoparticles,which were only with a lower refractive index difference with the surrounding medium,the color saturations of these particles were very low and their structural colors were not bright enough during the applications.This was further exacerbated when using hydrogel to replicate the colloidal crystals,which were usually restricted by the unobvious and low sensitive response to the stimuli.The text of this dissertation,we strive to find the appropriate method to fabricate a large number of photonic crystal materials with obvious color saturation and high brightness,and make them as a template for the preparation of inverse opal hydrogel in response to external stimuli.In the second chapter,we discussed the fabrication of a large number of droplets template with the electrostatic spraying device,studied the relationship between the droplet size and solution concentration,voltage intensity,receiving height,the size of tube diameter;and we main mainly discusses the fabrication of the high saturation photonic crystal films and photonic crystal microspheres in the second chapter.In the fourth chapter,we studied the preparation of inverse opal hydrogel microspheres with electric field response and pH response using photonic crystal microspheres as a template.The detail works are as follow:(1)The microdroplet preparation based on microfluidic technology: A device capable of preparing a large number of micro-droplets were set up.A uniform size droplet template is successfully prepared by simple experimental equipment with voltage source and capillary tube,to make sure it is possible to prepare a large number of photonic crystal microspheres.(2)A method was introduced to fabricate the high saturation photonic crystal microspheres: The suitable ink concentration was explored by means of physical doping.Two-dimensional photonic crystal films and three-dimensional photonic crystal microspheres were successfully prepared,characterizing by scanning electron microscopy and optical fiber spectroscopy.(3)The preparation of highly saturated photonic crystal inverse opal hydrogel microspheres: inverse opal microspheres with pH and electric field response had been prepared using the prepared photonic crystal microspheres as a template,achieving the detection of ions,and providing the possibility of later detection and display.