The Development Of Visible-fluorescent Dual-mode Hydrochromic Dyes Based On Rhodamine And Its Application

With the emergence of problems caused by environmental degradation and climate warming which influence human survival and development,the sustainable problems such as environmental protection and energy saving aroused people's attention increasingly.Among them,paper and all kinds of printing consumables occupies an important position.As a result,scientists in all nations are exploring ways to develop rewritable materials actively.In recent years,more and more materials based on the response of environmental stimulation were developed and rewritable paper realized.Our group had reported water-jet printing which is groundbreaking.In this work water acted as ink and writing-erasing realized by controlling water retention or remove on the paper,which solved the problems of paper waste.The way of display at current state has only one mode visible light,however,some of information transmission involved in special environment,therefore,it is of great significance to develop a visible-fluorescent dual-mode of hydrochromic material.In the second chapter,AM-Rh,the visible-fluorescent dual-mode of hydrochromic dye was modified based on NH₂-Rh.To enhance the water solubility of dye,AM-Rh was grafted to the polymer with water-solubility by the way of free radical polymerization.Four Poly?AM-Rh_x co NIPAM_y?s with different dye grafting ratios were obtained by changing raw ratio of copolymerization.In this work,we put forward a more effective methods via UV-vis absorption spectroscopy and provided details methods to calculate ratios of dyes grafted on polymer?x/y?by spectroscopy combined with GPC technologies.The four copolymers have good solubility in many common organic solvents and even in pure water,meanwhile preserving the hydrochromism of the dye monomer.The results showed that the hydrochromic properties,water-solubility,temperature-sensitive properties of the polymer and the fluorescence tunability were both seen in Poly?AM-Rh_x co NIPAM_y?s.At the same time,Poly?AM-Rh_x co NIPAM_y?s realize the solid state fluorescence and obtain higher fluorescence quantum yields after grafted to the polymer and the fluorescent intensity could be adjusted by controlling the proportion of AM-Rh and NIPAM.This provides reference for overcoming the aggregation induced fluorescence quenching for dyes.In the third chapter,in order to overcome the disadvanges of difficult synthesis of NH₂-Rh and Poly?AM-Rh_x co NIPAM_y?s were difficult to apply on a solid substrate,we take the commercialized rhodamine B as raw material.The visible-fluorescent dual-mode hydrochromic dyes were obtained by two-step modify,after that the hydrochromic property was investigated,therefore,Propyl-N-Rh with gorgeous color was selected.In this paper,the characteristics of hydrochromic and fluorescence in solution were learned and apply it to water-jet printing.What counts is high contrast and bright fluorescence exhibited on the water-jet printing paper.