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NANOPARTICLES DERIVED FROM A GROUP OF UNIFORM MATERIALS BASED ON ORGANIC SALTS Analytical Research Seminar Aaron Tesfai Warner Research Group Department.

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Presentation on theme: "NANOPARTICLES DERIVED FROM A GROUP OF UNIFORM MATERIALS BASED ON ORGANIC SALTS Analytical Research Seminar Aaron Tesfai Warner Research Group Department."— Presentation transcript:

1 NANOPARTICLES DERIVED FROM A GROUP OF UNIFORM MATERIALS BASED ON ORGANIC SALTS Analytical Research Seminar Aaron Tesfai Warner Research Group Department of Chemistry. Louisiana State University. Baton Rouge,LA 70803

2 Outline Introduction to Ionic Liquids (ILs) –Brief history –Common cation/anion combinations –Properties of ILs –Group of Uniform Materials Based on Organic Salts (GUMBOS) Synthesis and Characterization of Micro- and NanoGUMBOS –Surfactantless Melt-Emulsion-Quench –Surfactant-Assisted-Melt-Emulsion-Quench –Reverse Micelle Magnetic Particles from GUMBOS –Synthesis and characterization of [Bm 2 Im][FeCl 4 ] GUMBOS particles –Magnetic susceptibility of [Bm 2 Im][FeCl 4 ] GUMBOS particles

3 Ionic Liquids (ILs) Ionic liquids are defined as organic salts with melting points at or below 100 °C –Liquid 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 Walden Walden discovered the first ionic liquid, ethyl ammonium nitrate with a melting point of 12 °C in 1914 The term ILs used to distinguish these compounds from inorganic salts that melt at high temperature Low 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, 2238–2264 Del Po’polo, M. G.; Voth, G. A. J. Phys. Chem. B 2004, 108, P. Walden, Bull. Acad. Imper. Sci. (St. Petersburg) 1800 (1914)

4 Common Cations and Anions 1-alkyl pyridinium1-alkyl-3-methyl-imidazoliumTetraalkyl-phosphoniumTetraalkyl-ammonium Common cations: Common anions: R = Ethyl, Butyl, Hexyl, Octyl and DecylCommon alkyl (R-) chains: bis(trifluoromethylsulfonyl)imide nitratehexafluorophosphatetetrafluoroborate

5 Properties of Ionic Liquids Tunability Thermal stability Dissolve many organic and inorganic materials Low volatility Environmentally friendly

6 Group of Uniform Materials Based on Organic Salts (GUMBOS) 1,3,3-Trimethyl-2-[7-(1,3,3-trimethyl-1,3-dihydro- indol-2-ylidene)-hepta-1,3,5-trienyl]-3H-indolium bis(trifluoromethylsulfonyl)imide M.P. > 120 °C 1-butyl-2,3-dimethylimidazolium tetrachloroferrate M.P. -2 °C Bwambok et al. submitted to ACS Nano Tesfai et al. ACS Nano accepted.

7 Objectives To investigate the use of GUMBOS that are solid above room temperature for possible GUMBOS-based nano- and micro- particle synthesis To characterize the nano- and microGUMBOS Scanning Electron Microscopy (SEM) Transmission Electron Microscopy (TEM) Differential Interference Contrast (DIC) Fluorescence Microscopy Atomic Force Microscopy To dope the GUMBOS and investigate the possibility of using nanoGUMBOS to entrap various materials such as drug molecules

8 Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless Melt-Emulsion-Quench Surfactant-Assisted Melt-Emulsion-Quench Reverse Micelle

9 GUMBOS Used GUMBOSMelting pointMiscibility with H 2 O [1-butyl-2,3-dimethylimidazolium] [hexafluorophosphate] 42 °CNo [bm 2 Im][PF 6 ] [1-butyl-2,3-dimethylimidazolium] [hexafluorophosphate]

10 Surfactantless Synthesis of NanoGUMBOS 1. Add 25 mg of GUMBOS into 8 mL of DI water 2. Heat mixture at 70 °C 3. Homogenize solution for 10 min, Probe sonication for 10 min 4. Freeze mixture in an ice water bath Tesfai et al. Nano Lett. 2008, 8,

11 Characterization of NanoGUMBOS Electron micrographs of [bm 2 Im][PF 6 ] 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. TEMSEM Tesfai et al. Nano Lett. 2008, 8,

12 Surfactantless Synthesis: Nile Red Doped NanoGUMBOS Tesfai et al. Nano Lett. 2008, 8, AB C D (A) solid [Bm 2 Im][PF 6 ](B) melted [Bm 2 Im][PF 6 ](C) o/w emulsion(D) [Bm 2 Im][PF 6 ] nanoparticle crop

13 Surfactantless Synthesis : SEM and Optical Microscopy (DIC) and (Fluorescence) of microGUMBOS Solid [bm 2 Im][PF 6 ] 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,

14 Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless-Melt-Emulsion-Quench Surfactant Assisted-Melt-Emulsion-Quench Reverse Micelle

15 Surfactant-Assisted Synthesis of NanoGUMBOS 1. Add 1% w/v Brij-35 in DI water 2. Add 25 mg of GUMBOS to mixture and placed in water bath set to 70 °C 3. Homogenize solution for 10 min, Probe Sonication for 10 min 4. Freeze mixture in an ice water bath Tesfai et al. Nano Lett. 2008, 8,

16 Surfactant-Assisted Synthesis: TEM of NanoGUMBOS Representative TEM image of 45 ± 7 nm [bm 2 Im][PF 6 ] nanoGUMBOS synthesized using surfactant-assisted synthesis, employing Brij-35. Tesfai et al. Nano Lett. 2008, 8,

17 Synthesis and Characterization of Micro- and NanoGUMBOS Surfactantless-Melt-Emulsion-Quench Surfactant Assisted-Melt-Emulsion-Quench Reverse Micelle

18 Surfactant Employed for Reverse Micelle Synthesis: Aerosol-OT (AOT) Sodium bis(2-ethyl-hexyl)sulfosuccinate (AOT) Double chain amphiphile Able to form reverse micelles Able to solubilize water R value (w o ): [water]/[surfactant] AOT Reverse Micelle BulkHeptaneContinuum Inner Bulk Water AOT Interface Bound Water

19 Basic Processes for Nanoparticle Formation within AOT Reverse Micelles Tesfai et al. ACS Nano accepted 0.1 M AOT in 5 mL heptane 120 μL of M [Bm 2 Im][Cl] in water A 0.1 M AOT in 5 mL heptane 120 μL of M [Na][BF 4 ] in water B

20 TEM Images of [Bm 2 Im][BF 4 ] NanoGUMBOS Reagent Concentration (M) Particle Size (nm) Standard Deviation (nm) A: ± 2.2 B: ± 1.8 C: ± 4.8 D: ± 17 Tesfai et al. ACS Nano accepted

21 Size Distributions of [Bm 2 Im][BF 4 ] 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.

22 Tapping Mode AFM Images of [Bm 2 Im][BF 4 ] NanoGUMBOS A 12µm nm B 12µm C 2µm nm D 2µm A nm B C nm D (A) 60 × 60 μm 2 topographical image and (B) simultaneously acquired phase image. (C) Zoom-in view 12 × 12 μm 2 view and (D) corresponding phase channel. Tesfai et al. submitted to ACS Nano M [Bm 2 Im][BF 4 ] Tesfai et al. ACS Nano accepted.

23 Conclusions NanoGUMBOS (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 size Size control A 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.

24 Magnetic Particles From GUMBOS

25 Applications of Magnetic Nanoparticles Iron oxide magnetic nanoparticles injected In tumor Application of external magnetic field Superparamagnetic iron oxide nanoparticles are guided towards the lungs in the presence of an external magnetic field Amirfazli, A. Nature Nanotech. 2007, 8, Magnetothermal Drug Targeting

26 Objectives To investigate the use of magnetic GUMBOS for possible GUMBOS-based particle synthesis To characterize the GUMBOS particles Transmission Electron Microscopy (TEM) Atomic Force Microscopy

27 Magnetic Particles from GUMBOS Synthesis and characterization of [Bm 2 Im][FeCl 4 ] GUMBOS particles Magnetic susceptibility of [Bm 2 Im][FeCl 4 ] GUMBOS particles

28 Basic Processes for Magnetic Particle Formation within AOT Reverse Micelles. Tesfai et al. ACS Nano accepted. 0.1 M AOT in 5 mL heptane 120 μL of M [Bm 2 Im][Cl] in water A 0.1 M AOT in 5 mL heptane 120 μL of M [FeCl 3 ].6H 2 O in water B

29 TEM Images of Magnetic GUMBOS Particles Reagent Concentration (M) Particle Size (nm)Standard Deviation (nm) A: 0.398± 17 B: ± 26 Micrographs of magnetic [Bm 2 Im][FeCl 4 ] GUMBOS particles obtained from TEM revealing mean particle sizes of (A) 98.0 ± 17 nm and (B) ± 26 nm. Tesfai et al. ACS Nano accepted.

30 Size Distributions of Magnetic GUMBOS Particles [AOT] = 0.1 M; molar reagent concentrations: 0.3 and 0.4 M. Tesfai et al. ACS Nano accepted.

31 Tapping Mode AFM Images of [Bm 2 Im][FeCl 4 ] GUMBOS Particles (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. 0.3 M [Bm 2 Im][FeCl 4 ] 0.4 M [Bm 2 Im][FeCl 4 ]

32 Absorption Spectra of Bulk [Bm 2 Im][FeCl 4 ] Tesfai et al. ACS Nano accepted. 1 Hayashi, S. et al. Chem. Lett. 2004, 33,

33 Magnetic Susceptibility of Bulk [Bm 2 Im][FeCl 4 ] Alongside [Bm 2 Im][FeCl 4 ] NanoGUMBOS GUMBOSMagnetic Response (emu/g) [BmIm][FeCl4] x10 -6 [HmIm][FeCl4] x [OmIm][FeCl4] x Hayashi, S.; Hamaguchi, H.-o. Chemistry Letters. 2004, 33, GUMBOS/nanoGUMBOSMagnetic Response (emu/g) [Bm 2 Im][FeCl 4 ] GUMBOS 34.3 x [Bm 2 Im][FeCl 4 ] nanoGUMBOS 34.3 x Tesfai et al. ACS Nano accepted.

34 Conclusions Two distinct sizes of magnetic nanoGUMBOS were synthesized and characterized Particle size was influenced by increasing reagent concentration in each reverse micelle. UV-Vis spectrum confirmed the well known characteristic peaks of FeCl 4 for the bulk magnetic GUMBOS. Both the bulk and nanoGUMBOS demonstrated to be magnetic

35 Acknowledgements Prof. Isiah M. Warner Postdoctoral Research Associates Warner Research Group Garno Research Group National Science Foundation (NSF) National Institutes of Health (NIH) Phillip W. West Endowment


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