Preparation Of Dansylamode-based Fluorescence Nanochemosensor Of Hg²⁺ And The Study Of Its Properties

The main content of this paper is the preparation of the Hg2+ fluorescence nanochemosensor and the study of its properties. The work of this paper is been divided into three parts:(1) An inorganic-organic hybrid fluorescence chemosensor (DA/SBA-15) was prepared by covalent immobilization of a dansylamide derivative into the channels of mesoporous silica material SBA-15 via (3-aminopropyl)triethoxysilane (APTES) groups. The primary hexagonally ordered mesoporous structure of SBA-15 was preserved after the grafting procedure. Fluorescence characterization shows that the obtained inorganic-organic hybrid composite is highly selective and sensitive to Hg2+ detection, suggesting the possibility for real-time qualitative or quantitative detection of Hg2+ and the convenience for potential application in toxicology and environmental science.(2) A SBA-15-based two-input chemically controlled INH logic gate (DA/SBA-15) was realized by covalent immobilization of a dansylamide derivative into the channels of mesoporous silica material SBA-15. Addition of Hg2+ and Cl- or Br- ions were employed as the two inputs, and the fluorescence intensity of DA/SBA-15 was monitored as the output. It can be envisaged that a chemical logic gate array may be formed by attaching several different fluorophores on an individual SBA-15, and the logic gates could be further integrated for more complex operations at the nanoscale.(3) A fluorescence chitosan chemosensor (DA-CN) was successfully synthesized by a simple substitution reaction at the amino groups of chitosan nanoparticle (CN) with dansyl chloride. Further experiments showed that the fluorescence chitosan chemosensor had excellent dispersibility and stability in aqueous solution at ambient temperature. Fluorescence characterization showed that the obtained fluorescence probe based on CN could selectively and sensitively recognize Hg2+ over other metal ions in water within a broad pH span, suggesting the possibility for real-time qualitative or quantitative detection of Hg2+ and the convenience for potential application in biosensors, toxicology and environmental science.Besides, thermotropic liquid crystalline polyester (TLCP) was synthesized via low-temperature solution polycondensation from 1,4-Bis(4-Hydroxybenzoyloxy)butane (H4) and terephthaloyl dichloride. Polymer nanocomposites based on a small quantity of multi-walled carbon nanotubes (MWNTs) were prepared by in situ polymerization method. The wide-angle X-ray diffraction (WAXD) results suggested that the addition of MWNTs to TLCP matrix did not significantly changed the crystal structure of TLCP. The interactions between the molecules of the TLCP host phase and the carbon nanotubes were investigated through Raman spectroscopy investigations. We detected a distinct wave number shift of the radial breathing modes, confirming the carbon nanotubes interacted with the surrounding liquid crystal molecules, most likely through aromatic interactions ((?)-stacking). The interactions between liquid crystal host and nanotube guests were also evident from a polarizing microscopy (POM) study of the liquid crystal-isotropic phase transition in the proximity of nanotubes. The thermal properties and the morphological properties of the TLCP/MWNTs nanocomposites were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). TGA data demonstrated the addition of a small amount of MWNTs into TLCP matrix could improve the thermal stability of TLCP matrix. DSC results revealed that melt transition temperatures and isotropic transition temperatures of the hybrids were enhanced.