Combination Of Magnetic And Luminescent Properties, And Design Of Hierarchical Porous Mixed Metal Oxides Based On Layered Double Hydroxides

Layered double hydroxides as a new class of layered materials have attracted extensive attention due to their unique physical, chemical and other properties. The design of magnetic, luminescent layered double hydroxides, and their applications in drug delivery; The architecture of hierarchically porous or mesoporous mixed metal oxides derived for layered double hydroxides, and the increase of drug loading amount are of great practical significance. According to the current research on magnetic, luminescent layered double hydroxides, this thesis explored the synthesis of magnetic, luminescent layered double hydroxides by introduction of Fe3O4 nano-fluid and luminescent ions (Sm3+, Eu3+, Tb3+ and Dy3+); The intercalation of typical drug molecules (such as ibuprofen) and their controlled release behavior in simulated fluid (SBF). Based on the decomposition of layered double hydroxide under high temperature, this thesis established a method for preparing mesoporous layered double hydroxides and mixed metal oxides by using P123 as sacrifice template; proposed a navol gas-liquid route to build hierarchically porous mixed metal oxides without using any template.Compared with the dried F3O4 powder, Fe3O4 nano-fluid have rich hydroxyls, which can form "hydrogen" bonds with the hydroxyls in layered double hydroxides. The firm combination between Fe3O4 nanoparticles and layered double hydroxides resulted in a superparamagnetic property of obtained composites. When the Fe/Mg molar ratio is 30, Fe3O4 nanoparticles are uniformly distributed on the surface of layered double hydroxides, and no agglomeration of Fe3O4 can be found. In this condition, a relative high crystallized layered double hydroxides could be obtained, and it possessed superparamagnetic property with the saturation magnetization value of 1.75 emu/g.Rare-earth ions were used as luminescent center to replace Al3+ in layered double hydroxides crystal structure. By doping different rare-earth ions (Sm3+, Eu3+, Tb3+ and Dy3+), a series of luminescent layered double hydroxides were prepared. The influences of different rare-earth ions, as well as their doping concentrations on the crystal structure of layered double hydroxides were investigated. Meanwhile, in order to avoid the concentration quenching phenomenon of rare earth ions, the optimal doping amount of each ion was obtained after careful analysis. For Sm-doped layered double hydroxides, the optimal doping amount of Sm3+ is 1.82% (mole percent), and its emission spectrum is dominated by the green light at 576 nm; For Eu-doped layered double hydroxides, the optimal doping amount of Eu3+ is 5.43%, and its emission spectrum is dominated by the red light at 610 nm; For Tb-doped layered double hydroxides, the optimal doping amount of Tb3+ is 6.71%% (mole percent), and its emission spectrum is dominated by the blue light at 542 nm; For Dy-doped layered double hydroxides, the optimal doping amount of Dy3+ is 1.7% (mole percent), and its emission spectrum is dominated by the green and red light at 576 and 617 nm, respectively.Ibuprofen intercalated magnetic and luminescent layered double hydroxides were successfully synthesized by using Eu3+ as emission center, FeO4 nano-fluid as magnetic substrate. The ibuprofen loading amount is 31 wt%. This composite has a saturation magnetization value of 1.86 emu/g, and can emit red light at 610 n, under ultraviolet light. In simulated body fluid (SBF), the functional layered double hydroxides have the characteristics of sustained release of ibuprofen. Compared with a simple physical mixture of layered double hydroxides and ibuprofen, the ibuprofen molecules were intercalated in layered double hydroxides layers through electrostatic force, which gives a sustainable release time of 12 h. The magnetic, luminescent layered double hydroxides organic-inorganic composite materials have potential applications in the field of targeted drug delivery and luminescent probes.Based on the previous reports on the synthesis if 3-dimentional macroporous layered double hydroxides structure via soft template method, this paper discussed the construction of ordered mesoporous mixed metal oxides using three-block copolymer PI23 as sacrifice template. When P123 amount was 2.0 wt%, the obtained mixed metal oxides prepared through calcination at 500℃for 5 h has higher specific surface area and pore volume, which are 108.1 m2/g and 0.24 cm3/g, respectively. Ethanol extraction and calcination procedure were used to remove P123. Results reveal that the former product was layered double hydroxides with microporous structure, and the latter product was mixed metal oxides with ordered mesoporous structure. Finally, the existence of ordered mesopores was employed to increase ibuprofen loading capacity. Through the "memory effect" of layered double hydroxides, both no-mesoporous and mesoporous mixed metal oxides were chose to reconstruct layered double hydroxides at the presence of ibuprofen in an alkaline solution. XRD analysis indicated the successful recovery of ibuprofen intercalated layered double hydroxides. And for the former products, ibuprofen loading amount was 20.6 wt%, the latter product, owing to the mesoporous channels, the ibuprofen loading amount was 35.4 wt%.Finally, we established a gas-liquid interface reaction to fabricate hierarchically porous mixed metal oxides. Layered double hydroxides gel was used as precursor for calcination. The mixed metal oxides skeleton exhibits a wide pore size distribution covering the range of micropores, mesopores and macropores. The results further suggest the instantaneous formation of network porous structure was dependent on the explosive decomposition of bis(2-hydroxyethyl) oxalate in layered double hydroxides gel, which will provide an effective experimental method to produce other mixed metal oxides.