Light Responsive Polymer Hollow Core Ball And Azobenzene Modify The Preparation Of Graphene Oxide

Stimuli responsive polymeric materials can adjust themselves under external stimuli so as to adapt to the change of the outer environment, such as regulation of hydrophilic-hydrophobic properties of surfaces, control of ionic and molecular transportations, and transformation of chemical signals into light, electric, thermal and mechanical signals. Therefore, they have wide applications in every aspect of our lives. Stimuli responsive hollow polymer microspheres have been a research focus recently.Due to their stable and easily controllable structure, they have potential applications in drug delivery, chemical catalyst, nano and micro reactors. In this work, azobenzene-containing hollow polymer microspheres were successfully synthesized via distillation-psrecipitation polymerization techniques. Studies about the formation conditions, as well as the photo-responsive functionality of the hollow polymer microspheres were also investigated.Firstly, the sol-gel method was utilized to synthesize the monodispersed, carbon doublebond-containing silica microspheres. Silica/polymer microspheres were then synthesized and prepared by distillation-precipitation polymerization.The hollow microspheres were obtained after corrosion in hydrofluoric acid. This kind of hollow microspheres showed photo responsiveness. The hollow microspheres shrank when exposed to the ultraviolet light and returned to the initial size when exposed to the visible light. This process relies on the photoisomerization of the azobenzene moiety.This kind of photo-sensitive feature could be used to realize controlled release of the encapsulated substance and micro reaction containers by irradiation of ultraviolet light and visible light.Graphene has been researched a lot recent years due to its special functionalities.In order to promote its functionality,researchers have reported methods of surface-grafting of orgnic molecules.Based on the achievements of light-responsive materials of this group, this article shows the preparation of oxhydryl-grafted graphene which was carried out by oxidation-reduction reaction with hydrazine hydrate as the reducing agent and the synthesis of azobenzene-containing graphene which was carried out by esterification reaction in the presence of azobenzene-containing monomer.The factors (solvent, reaction temperature and the catalyst) that influenced the esterification reaction process were also analized.This work provides the reaserch of photo-responsive graphene with important basis.