Synthesis Of Mesoporous Silica Nanomaterials And The Application In Room Temperature Phosphorescence Analysis

In the first part of this dissertation,the author systematicly reviewed and commented the previous reports on mesoporou slica nanomaterials?MSN?.MSNs,which have high density and ordered pore structure,are a series of materials with advantage of good stability in water and high surface area.MSN are often synthesized by surfanctant tamplating methods.By employing surfactants with different molecular structure,and adjusting the reaction temperature,reation time,hydrothermal treatment strategy,MSN materials with various pore sizes,pore structures,particle sizes,and surface properties can be synthesized to meet more application needs.Despite its widely attentions earned on the application of drug delivering/releasing and electrochemical analysis based on its uniqe material structure and properties,application of MSN in the field of room temperature phosphorescence?RTP?is rare.In order to eliminate quenching on the triple excited state of phosphors by oxygen or other quenchers,various RTP protective techniques were developed to offer phosphors more stable luminescent conditions,and to improve the detection sensitivity.Solid substrate RTP,micelle stabilized RTP,supermolicular induced RTP,and noneprotective RTP are most oftenly,and successfully used in different application occasions.In contrast,MSN may also have wide application potential benefited from its superior adsorption properties.In the second part,the author used surfactant Cetyltrimethyl Ammonium Bromide?CTAB?as the template to synthesize high dispersive MCM-41 style MSN.What's more,by employing mesitylene as swelling agent,LPMS1 and LPMS2,two 2D mesostructreu materials with larger pore size were synthesized.The two MSNs also have similar high dispersity and unique morphology with MCM style.Influence of the pre-stirring time on the morphology unity of LPMS1-2 was investigated,and it was found that a 3 hour of pre-stirring is necessary in synthesing of high quality and unique LPMS1 and LPMS2.Next,the author used triblock copolymers F127 as template,and KCl as stabilizer to synthesize 3D pore structural MSN with larger pore at temperature lower than room temperatrue,and named material as LPMS3.LPMS3 is cubic face centered in morphology.Also using F127 as template,KCl as stabilizer,and TMB as swelling agent,MSN material with 3D ultra large pore and morphology of hexagonal block was successfully synthesized.Both the two large pore materials can be monodispersed into water,and the sulotions were ideally stable.Another two MSN materials with hollow structure were also synthesized using PVP-CTAB as co-tamplate under 313 K and 333 K,respectively.The two materials possess“Cashew”and“Bread”morphologies.Their hollow strutrue were indirectly proved by SEM analysis.All the above mentioned materials were surface modified by esterification reaction and silane coupling method.After graft of cyclohexyl to these materials,MSNs show weak interacitons between particles and are very poor dispersity when added to water.Based on all these MSN materials synthesized above,a novel MSN-surfactant synergistic substrate was proposed for RTP sensing/analysis.The synergistic substrate which exhibited strong RTP induceing ability?increased by over 50 times compared with single micelle mediums?and rapid RTP inducing speed is based on the hydrogen bonding interactions between the Si-OH on the MSN inner pore surface and hydroxyl groups in the hydrophobic side of sodium deoxycholate?NaDC?molecules.The hydrophilic inner pore cavity was then converted to hydrophobic one when the hydrophilic side of NaDC attached to the inner surface of MSN pore,resulting better adsorptive ability toword various water-insoluble compounds.The interactions were demonstrated by a series of tests including UV spectral analysis,centrifugation treatment and comparision analysis,varing MSN/NaDC proportion detections,and adsorption dynamics under MSN with different pore sizes.Besides,the synergistic substrate also shows advantages such as good RTP-inducing stability against temperature variations,and wide application range to include various analytes with different molecule sizes.The latter superiority were demonstrated by successful application in detection of 5 PAHs include naphthaline,phenanthrene,anthracene,pyrene,and benzo?k?fluoranthene.The synergistic substrate RTP analysis can be conducted on conventional instrument and without using large volume of organic solvents.The simple detection steps and the ideal analytical performance compared with previous reports all demonstrated the great application potential of the synergistic substrate in RTP.Finally,the author porposed a novel commercial available fluorescent method to detect trace Pd²⁺in water and solide samples.Pd²⁺played a role of both the analyte and catalyst.Under the catalysis of Pd²⁺and acid condition,9-BrP was converted to phenanthrene,which emits far stronger fluorescence.The catalysis reaction was demonstrated by UV spectra analysis,cyclic voltammetry,and HPLC methods.Various common cations and anions include Pd⁴⁺,Pd⁰ were investigated,and no interference was found from these ions.Application of the method not only avoids complicate organic synthesis,but also shows ideal analytical performance.