Presentation on theme: "Analytical Research Seminar"— Presentation transcript:
1Analytical Research Seminar NANOPARTICLES DERIVED FROM A GROUP OF UNIFORM MATERIALS BASED ON ORGANIC SALTSAnalytical Research SeminarAaron TesfaiWarner Research GroupDepartment of Chemistry.Louisiana State University. Baton Rouge,LA 70803
2Outline Introduction to Ionic Liquids (ILs) Brief history Common cation/anion combinationsProperties of ILsGroup of Uniform Materials Based on Organic Salts (GUMBOS)Synthesis and Characterization of Micro- and NanoGUMBOSSurfactantless Melt-Emulsion-QuenchSurfactant-Assisted-Melt-Emulsion-QuenchReverse MicelleMagnetic Particles from GUMBOSSynthesis and characterization of [Bm2Im][FeCl4] GUMBOS particlesMagnetic susceptibility of [Bm2Im][FeCl4] GUMBOS particles
3Ionic Liquids (ILs)Ionic liquids are defined as organic salts with melting points at or below 100 °CLiquid at room temperature (room temperature ionic liquids RTILs)Solid above room temperature (frozen ionic liquids)The name ILs was first used by a Latvian-German chemist Paul WaldenWalden discovered the first ionic liquid, ethyl ammonium nitrate with a melting point of 12 °C in 1914The term ILs used to distinguish these compounds from inorganic salts that melt at high temperatureLow melting point - asymmetry between the ions prevent formation of stable crystal lattice (“frustrated crystal packing”)Welton T. Chem Rev 1999, 99,Philippe Hapiot and Corinne Lagrost Chem. Rev. 2008, 108, 2238–2264Del Po’polo, M. G.; Voth, G. A. J. Phys. Chem. B 2004, 108,P. Walden, Bull. Acad. Imper. Sci. (St. Petersburg) 1800 (1914)
4Common Cations and Anions 1-alkyl pyridinium1-alkyl-3-methyl-imidazoliumTetraalkyl-phosphoniumTetraalkyl-ammoniumR = Ethyl, Butyl, Hexyl, Octyl and DecylCommon alkyl (R-) chains:Common anions:bis(trifluoromethylsulfonyl)imidehexafluorophosphatetetrafluoroboratenitrate
5Properties of Ionic Liquids TunabilityThermal stabilityDissolve many organic and inorganic materialsLow volatilityEnvironmentally friendly
6Group of Uniform Materials Based on Organic Salts (GUMBOS) 1-butyl-2,3-dimethylimidazolium tetrachloroferrateM.P. -2 °C1,3,3-Trimethyl-2-[7-(1,3,3-trimethyl-1,3-dihydro-indol-2-ylidene)-hepta-1,3,5-trienyl]-3H-indolium bis(trifluoromethylsulfonyl)imideM.P. > 120 °CTesfai et al. ACS Nano accepted.Bwambok et al. submitted to ACS Nano 2009.
7ObjectivesTo investigate the use of GUMBOS that are solid above room temperature for possible GUMBOS-based nano- and micro- particle synthesisTo characterize the nano- and microGUMBOSScanning Electron Microscopy (SEM)Transmission Electron Microscopy (TEM)Differential Interference Contrast (DIC)Fluorescence MicroscopyAtomic Force MicroscopyTo dope the GUMBOS and investigate the possibility of using nanoGUMBOS to entrap various materials such as drug molecules
8Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless Melt-Emulsion-QuenchSurfactant-Assisted Melt-Emulsion-QuenchReverse Micelle
9GUMBOS Used [bm2Im][PF6] [1-butyl-2,3-dimethylimidazolium] [hexafluorophosphate]GUMBOSMelting pointMiscibility with H2O[1-butyl-2,3-dimethylimidazolium] [hexafluorophosphate]42 °CNo
10Surfactantless Synthesis of NanoGUMBOS 1. Add 25 mg of GUMBOS into 8 mL of DI water2. Heat mixture at 70 °C3. Homogenize solution for 10 min, Probe sonication for 10 min4. Freeze mixture in an ice water bath1243Tesfai et al. Nano Lett. 2008, 8,
11Characterization of NanoGUMBOS SEMTEMElectron micrographs of [bm2Im][PF6] nanoGUMBOS synthesized using surfactantless synthesis: (a) SEM image showing an average nanoparticle diameter of 90 ± 32 nm. (b) TEM image with an average nanoparticle diameter measured as 88 ± 34 nm.Tesfai et al. Nano Lett. 2008, 8,
12Surfactantless Synthesis: Nile Red Doped NanoGUMBOS (A) solid [Bm2Im][PF6](B) melted [Bm2Im][PF6](C) o/w emulsion(D) [Bm2Im][PF6] nanoparticle cropTesfai et al. Nano Lett. 2008, 8,
13Surfactantless Synthesis : SEM and Optical Microscopy (DIC) and (Fluorescence) of microGUMBOS Solid [bm2Im][PF6] microGUMBOS with average diameters of ~ 3-μm imaged with (a) SEM, (b) Optical microscopy (DIC), (c) Optical microscopy (fluorescence), (d) Overlay of DIC and fluorescence.Tesfai et al. Nano Lett. 2008, 8,
14Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless-Melt-Emulsion-QuenchSurfactant Assisted-Melt-Emulsion-QuenchReverse Micelle
15Surfactant-Assisted Synthesis of NanoGUMBOS 1. Add 1% w/v Brij-35 in DI water2. Add 25 mg of GUMBOS to mixture and placed in water bath set to 70 °C3. Homogenize solution for 10 min, Probe Sonication for 10 min4. Freeze mixture in an ice water bath1324Tesfai et al. Nano Lett. 2008, 8,
16Surfactant-Assisted Synthesis: TEM of NanoGUMBOS Representative TEM image of 45 ± 7 nm [bm2Im][PF6] nanoGUMBOS synthesized using surfactant-assisted synthesis, employing Brij-35.Tesfai et al. Nano Lett. 2008, 8,
17Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless-Melt-Emulsion-QuenchSurfactant Assisted-Melt-Emulsion-QuenchReverse Micelle
18Surfactant Employed for Reverse Micelle Synthesis: Aerosol-OT (AOT) Sodium bis(2-ethyl-hexyl)sulfosuccinate (AOT)Double chain amphiphileAble to form reverse micellesAble to solubilize waterR value (wo): [water]/[surfactant]AOT Reverse MicelleBulkHeptaneContinuumInner Bulk WaterAOT InterfaceBound Water
19Basic Processes for Nanoparticle Formation within AOT Reverse Micelles 0.1 M AOTin 5 mL heptane120 μL of M[Bm2Im][Cl]in waterA[Na][BF4]BTesfai et al. ACS Nano accepted
21Size Distributions of [Bm2Im][BF4] NanoGUMBOS Synthesized in water-containing AOT reverse micelles at various reagent concentrations: [AOT] = 0.1 M; molar reagent concentrations: 0.2, 0.4, 0.5, and 0.6 M.Tesfai et al. ACS Nano accepted.
22Tapping Mode AFM Images of [Bm2Im][BF4] NanoGUMBOS 220 nm220 nmBB0.4 M [Bm2Im][BF4]12m12mCC200 nm200 nmDD2m2m(A) 60 × 60 μm2 topographical image and (B) simultaneously acquired phase image. (C) Zoom-in view 12 × 12 μm2 view and (D) corresponding phase channel.Tesfai et al. submitted to ACS NanoTesfai et al. ACS Nano accepted.
23ConclusionsNanoGUMBOS (SEM) were obtained with average diameters of 90 nm using Surfactantless-Melt-Emulsion-Quench-Technique.TEM was in good agreement with SEM yielding average diameters of 88 nm (Surfactantless-Melt-Emulsion-Quench-Technique).MicroGUMBOS (SEM) were obtained with average diameters of ~3 μm (Surfactantless-Melt-Emulsion-Quench-Technique).Doping the microGUMBOS suggests that they may be used to entrap various materials including drugs.The use of an emulsifying agent (Surfactant-Assisted-Melt-Emulsion-Quench-Technique)yields nanoGUMBOS of ~45 nm in diameter.Smaller particle sizeSize controlA facile and reproducible method for synthesizing four distinct sizes of nanoGUMBOS has been developed (Reverse Micelle Synthesis).NanoGUMBOS size was influenced by increasing reagent concentration within each reverse micelle.
25Applications of Magnetic Nanoparticles MagnetothermalIron oxide magnetic nanoparticles injectedIn tumorApplication of external magnetic fieldDrug TargetingSuperparamagnetic iron oxide nanoparticles are guided towards the lungs in the presence of an external magnetic fieldAmirfazli, A. Nature Nanotech. 2007, 8,
26ObjectivesTo investigate the use of magnetic GUMBOS for possible GUMBOS-based particle synthesisTo characterize the GUMBOS particlesTransmission Electron Microscopy (TEM)Atomic Force Microscopy
27Magnetic Particles from GUMBOS Synthesis and characterization of [Bm2Im][FeCl4] GUMBOS particlesMagnetic susceptibility of [Bm2Im][FeCl4] GUMBOS particles
28Basic Processes for Magnetic Particle Formation within AOT Reverse Micelles. 0.1 M AOTin 5 mL heptane120 μL of M[FeCl3].6H2Oin waterB0.1 M AOTin 5 mL heptane120 μL of M[Bm2Im][Cl]in waterATesfai et al. ACS Nano accepted.
29TEM Images of Magnetic GUMBOS Particles Micrographs of magnetic [Bm2Im][FeCl4] GUMBOS particles obtained from TEM revealing mean particle sizes of (A) 98.0 ± 17 nm and (B) ± 26 nm.Reagent Concentration (M)Particle Size (nm)Standard Deviation (nm)A: 0.398± 17B: 0.4199± 26Tesfai et al. ACS Nano accepted.
30Size Distributions of Magnetic GUMBOS Particles [AOT] = 0.1 M; molar reagent concentrations: 0.3 and 0.4 M.Tesfai et al. ACS Nano accepted.
31Tapping Mode AFM Images of [Bm2Im][FeCl4] GUMBOS Particles 0.3 M [Bm2Im][FeCl4]0.4 M [Bm2Im][FeCl4](A) Topographical image of magnetic nanoGUMBOS with a diameter near 100 nm and (B) the matching phase image. (C) Topography of 200-nm GUMBOS Particles and (D) the corresponding phase frame.Tesfai et al. ACS Nano accepted.
32Absorption Spectra of Bulk [Bm2Im][FeCl4] Tesfai et al. ACS Nano accepted.1Hayashi, S. et al. Chem. Lett. 2004, 33,
33Magnetic Susceptibility of Bulk [Bm2Im][FeCl4] Alongside [Bm2Im][FeCl4] NanoGUMBOS Magnetic Response (emu/g)[BmIm][FeCl4]1 40.6x10-6[HmIm][FeCl4]x 10-6[OmIm][FeCl4]x 10-6GUMBOS/nanoGUMBOSMagnetic Response (emu/g)[Bm2Im][FeCl4] GUMBOS34.3 x 10-6[Bm2Im][FeCl4] nanoGUMBOS1Hayashi, S.; Hamaguchi, H.-o. Chemistry Letters. 2004, 33, 1590.Tesfai et al. ACS Nano accepted.
34ConclusionsTwo distinct sizes of magnetic nanoGUMBOS were synthesized and characterizedParticle size was influenced by increasing reagent concentration in each reverse micelle.UV-Vis spectrum confirmed the well known characteristic peaks of FeCl4 for the bulk magnetic GUMBOS.Both the bulk and nanoGUMBOS demonstrated to be magnetic
35Acknowledgements Prof. Isiah M. Warner Postdoctoral Research AssociatesWarner Research GroupGarno Research GroupNational Science Foundation (NSF)National Institutes of Health (NIH)Phillip W. West Endowment35