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Hybrid POSS Lecture 12 Class 2B: Inorganic and organic polymeric phases are mixed and form covalent interactions. tin oxides and polymers with carboxylate groups. But not a lot in the literature. Cross-linking through fullerenes. Used to purify C 60 . Did not look at mechanical properties
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Hybrid POSS Lecture 12Class 2B:Inorganic and organic polymeric phases are mixed and form covalent interactions
tin oxides and polymers with carboxylate groups. But not a lot in the literature
Cross-linking through fullerenes Used to purify C60. Did not look at mechanical properties Requires solvent to prepare
Cross-linking through fullerenes: my new idea Liquid polymer- no solvent needed
Grafted triethoxysilyl groups on polyethylene for moisture crosslinking May also be applied with vinyltriethoxysilane and RF plasma Excellent for moisture curing polyethylene
Anisotropic Micellar Nanoobjects from Reactive Liquid Crystalline Rod−Coil Diblock Copolymers Macromolecules, 2004, 37 (10), pp 3532–3535
Hydrogenated polybutadiene telechelics with triethoxysilyl groups Macromolecules 1992,25, 5742-5751
Triethoxysilyl terminated polysulfone TiO2 sol in THF Anneal > 200 °C Tailorable refractive index 1.6 < n < 1.8 Macromolecules 1991;24:3449–50.
Drug delivery hybrid gel Polyethylene glycol Treithoxysilyl group on each end Urea linkage
PEO Bridged polysilsesquioxane hybrids • Bacteriocide Ag-silsesquioxane coatings Biomacromolecules, 2007, 8 (4), pp 1246–1254 • Polymer electrolytes Solid State Ionics, 1999, 116, 197–209 • Coatings for steel. Adv. Technology 2008, 27, 117-126 • Electrochemically deposited coatings for stints New J. Chem., 2009, 33, 1596-1604 • Luminescent materials J. Non-Crystal Solids 2006, 352, 2292–2295 & Chem. Mater., 2004, 16 (13), pp 2530–2543 • Contolled druge release Chem. Mater., 2009, 21 (3), pp 463–467
PEO bridged polysilsesquioxanes for polymer electrolytes New J. Chem., 2012, 36, 1218-1223
Templating of structures and pores in hybrids, inorganics and organics In templating, you build a material around some molecule, macromolecules or liquid crystal Opals were used as templates for inverse opals and photonic solids (described in an earlier lecture). First we will see polymers phase segregation during sol-gel polymerization generating bone linke structures in hybrids. Then we will look at liquid crystalline surfactant or block copolymer templates
Using other phase separations to control how particles aggregate Smaller structures Hydrophilic Phase Surfactants Polymers Block copolymers Hydrolyzed monomers and polymers are often dissolve in this phase Hydrophobic Phase Larger structures Monomers are often dissolve in this phase Polymers are not very soluble in each other and will phase separate like oil and water
The Mobil patent was duplicating something already in the literature Somebody did not do a careful literature search!!!!!!
Traditional ionic surfactants used in mesoporous materials templation
Traditional non-ionic surfactants used in mesoporous materials templation
MCM-41 MCM-48 SBA-1 SBA-16 FDU-12 FDU-2 Pore models of mesostructures with symmetries of (A) p6mm, (B) Ia3̄d, (C) Pm3̄n, (D) Im3̄m, (E) Fd3̄m, and (F) Fm3̄m.
A few nanometers in diameter First model for surfactant templating: assumes liquid crystal occupies entire solution
Published in: Avelino Corma; Chem. Rev. 1997, 97, 2373-2420.
Synthesis of MCM-41 spheres 1) n-Hexadecyltrimethylammonium bromide (2.5 g, 0.007 mol) was dissolved in deionized water (50 g) 2) To this surfactant solution, 13.2 g of aqueous ammonia (32 wt.%, 0.25 mol) and 60.0 g of absolute ethanol (EtOH, 1.3 mol) were added and the solution was stirred for 15 min (250 rpm). 3) TEOS (4.7 g, 0.022 mol, freshly distilled) was added at one time resulting in a gel. 4) After stirring for 2 h the white precipitate was filtered and washed with 100 ml of deionized water and 100 ml of methanol. 5) After drying overnight at 363 K, the sample was heated to 823 K (rate:1 K min−1) in air and kept at that temperature for 5 h. Microporous and Mesoporous Materials, 1999, 27, 207–216
Synthesis of MCM-41 silica spheres X-ray diffraction pattern of an MCM-41 sample prepared in heterogeneous medium with n-hexadecylpyridinium chloride as template. Microporous and Mesoporous Materials, 1999, 27, 207–216
Size of MCM 41 pores can be controlled by process conditions
A close look at the structure shows that it is made of small amorphous silica particles TEM image of the honeycomb structure of MCM-41 and a schematic representation of the hexagonal shaped one-dimensional pores. > 1 nm in size Just like the silica in living sponges
X-Ray Diffraction (XRD) These materials show peaks at very small angles = larger structures than are typical in crystalline materials
formation mechanism of the templated nanoporous silicas New mechanism has individual surfactant molecules and micelles playing a role in developing architecture
. Chem. Rev., 2002, 102 (11), pp 4093–4138 Zeolite: silicalite
What are some of these materials and what do they look like (SBA-Santa Barbara. Electron micrographs of SBA-1 and SBA-6 along [100] Structure of SBA-1 or SBA-6 observed as an electron density and described either in terms of a clathrate structure or as a surface enveloping the micellar templating agents Nature, 2000, 408, 449
Plane-projection of CDF (a), respective TEM image fragment (b) and its simulation (c).
Chem. Mater., 1996, 8, 1141 Electronic density maps and bicontinuous cubic structure of MCM-48
HREM images of CMK-4 along the three zone axes [100], [110] and [111] together with a representation of the carbonaceous surface. J. Phys. Chem. B, 2002, 106, 1256
How organic templates can control porosity of materials Chem. Rev., 2011, 111 (2), pp 765–789
Monomer starts reacting and interacting with surfactant as the liquid crystal forms Liquid crystal forms then monomer enters and reacts
Making Hybrid Materials: Class 2C(Templating) Shown here with block copolymer
Tools for hierarchical materials structures Phil. Trans. R. Soc. A 28 April 2009 vol. 367 no. 1893 1587-1605
Other challenges • Ladder polysilsesquioxanes = super strong materials • Pure polyhedral analogs the size of C60 • Fundamentals of particle formation and connectivity at nm length scale • Mechanochemical direction of materials-like exercising developing muscles
Good-byeThank youGood LuckI will be here until November 23& should be back this summer