Development Of Stimulus-responsive Nanomaterials Based On Surface Modification Of Halloysite Nanotubes

This paper focuses on the preparation of stimuli-responsive nanomaterials.And the presence of hydrogen peroxide（H₂O₂）and hypochlorite（Cl O^-）in the environment is detected and treated.As common reactive oxygen species（ROS）,H₂O₂ and Cl O^-are widely present in living organisms and the environment,and they play an important role in biological immune regulation and environmental changes.By detecting the changes of H₂O₂ and Cl O^-levels in body tissues,we can more visually understand the pathology around tissues and organs,which plays an important role in disease prevention.Besides,hydrogen peroxide（H₂O₂）and hypochlorite（Cl O^-）are also one of the common components in domestic water and wastewater.The development of nanomaterials with stimulus response to H₂O₂ and Cl O^-is of great significance to the detection and removal of H₂O₂ and Cl O^-in water,and it has good application prospects.HNTs as purely natural nanotubular structures with high aspect ratio and large lumen volume and good dispersion in water,can be used to prepare stimuli-responsive nanomaterials by introducing reactive groups into their surface structures.The main studies are as follows:Chapter 1:This chapter mainly introduces the information about stimulus-responsive nanomaterials and the advantages of HNTs as stimulus-responsive materials.It also presents the purpose and significance of the research in this paper.Chapter 2:This chapter focuses on the preparation of coumarin derivatives containing diaminomaleonitrile active units on the surface of HNTs with hypochlorite stimulation-responsive nanomaterials（HNTs-probe）.The modified HNTs are added to a solution containing hypochlorite,the diaminomaleonitrile group can be converted into substituted imidazole formation with strong emission upon Cl O^-,which trigger a dramatically“turn-on”fluorescence change and reduce the Cl O^-into eco-friendly chloridion（Cl^-）.And the probe reduces Cl O^-to the more friendly chloride ion（Cl^-）.The HNTs-probe was also tested with other ions and the results showed that it has a higher selectivity for hypochlorite than other ions and also has the ability to remove it.These indicate that the smart nanocomposite is expected to be used in the synchronous detection and removal of Cl O^-in aqueous solutions,paving a novel path in water quality monitoring and wastewater treatment.Chapter 3:In this chapter,phenanthrene-9-boronic acid was modified on the inner surface of HNTs,and an H₂O₂ stimulus response system based on the B-C bond was constructed.In this system,when H₂O₂ is present,the B-C bond in the HNTs-Ph probe will be broken,and the9-hydroxyphenanthrene generated will easily aggregate in the aqueous medium,causing fluorescence quenching and reducing the fluorescence intensity of the material.We also studied the different ratios of HNTs and phenanthrene-9-boronic acid to prepare fluorescent probes with different grafting rates and compared the response performance of different grafting rates to H₂O₂ for the study.The results also show that when the amount of phenanthrene-9-boronic acid is added,the higher the grafting rate,the better its detection effect of H₂O₂,which provides a new idea for the surface modification of HNTs.Chapter 4:This chapter focuses on the synthesis of Fe³⁺-stimulated responsive fluorescent probes.Using the coumarin derivatives synthesized in Chapter 2,the fluorescent probes with Fe³⁺stimulation response were prepared by modifying acetylacetone and isoniazid onto the outer surface of HNTs.The probe formed a conjugated structure with Fe³⁺,which produced a paramagnetic effect and caused a decrease in fluorescence intensity.The probe also exhibits strong ion selectivity for Fe³⁺,making a useful attempt to prepare a single selective fluorescent probe.