Experiments • Synthesis of Nano Particles and Encapsulation • Synthesis of Hexagonal Mesoporous Silica & Carbon • Synthesis of Organic and Carbon Xerogels • Synthesis of Silver NanoWires Demostration Experiments • Sol-Gel Synthesis via TMOS • Sol-Gel Synthysis using Sodium silicate better known as furnace cement. • Ultrasonic synthesis of TMOS SOL-GEL SCIENCE Mix the reactives • Gelification Hydrolysis and Condesation reactions take place Sol • Aging • Soaking Gelification Gel Aging Drying Gel Aerogel Gelification OR + Si OR Mix reactives OR OR H2O OR OR OR OR Hydrolysis and Condesation reactions take place OR + Si OR OR HO OR Si OR Gel OH + HO OR OR Aging Gel O Si OR OR Sol Gelification OR OR Si OR OR OR + ROH + H2O OR Si OR OR OR OR Si ROH OR OR Si OR + Si HO O Si OR OR Designing Nanomaterials First Step Silica Solution Precursor: Tetraetilortosilicate Si(OCH2CH3)4 Solvent: Ethanol Catalyst: OxalicAcid Modifications pH (final product) Temperature (crystal phase) Precursor (Type of material) Time (Strength) etc (I) SOL-GEL SYNTHESIS OF AEROGELS Aerogels are a unique, nanostrutured material derived from gels. Gels are a novel class of material exhibiting solid-like behavior although consisting predominantly of a liquid phase. Their solidity derives from a continuous interpenetrating framework that, in essence, acts like a molecular scaffold extending throughout the liquid. This perspective of a gel as a molecular web in a liquid has found many industrial applications. Figure 1: A silicon oxide low density aerogel Gelification OR + Si OR Mix reactives OR OR H2O OR OR OR OR Hydrolysis and Condesation reactions take place OR + Si OR OR HO OR Si OR Gel OH + HO OR OR Aging Gel O Si OR OR Sol Gelification OR OR Si OR OR OR + ROH + H2O OR Si OR OR OR OR Si ROH OR OR Si OR + Si HO O Si OR OR Synthesis of Nano Particles and Encapsulation • Synthsis of Tiatnium and silica nanoparticles • Sol-Gel Encapsulation • Jorge Arias Encapsulated Dendrimer • The following figure shows mono dispersed Starburst PAMAM polyamidoamine dendrimers encapsulated in a sol-gel matrix of silica at 25 wt. %. Surface area analysis shows the material surface area was 617 m2/g. The dark spheres in Figure 1 dispersed throughout the silica matrix show diameters similar to their hydrodynamic values for this dendrimer in solution. PAMMA Dendrimer Sol-Gel Encapsulated Dendrimer Gelification OR + Si OR Mix reactives OR OR H2O OR OR OR OR Hydrolysis and Condesation reactions take place OR + Si OR OR HO OR Si OR Gel OH + HO OR OR Aging Gel O Si OR OR Sol Gelification OR OR Si OR OR OR + ROH + H2O OR Si OR OR OR OR Si ROH OR OR Si OR + Si HO O Si OR OR Synthesis of Hexagonal Mesoporous Silica & Carbon • This lab couples the hydrolysis and condensation of TEOS or other silica sources with Structure directing agents such as surfactants or polymers . • It also uses the final silica mesoporous material as a template to synthesize a high surface area, hexagonal pure carbon material. • Phong Nugyen, instructor MESOPOROUS ZEOLITE-TYPE MATERIALS The uniqueness of surfactant templated materials allows a variety of metal oxides to be formed with uniform honeycomb structure and surface area approaching 1000 m2/g. Surfactant templated materials have already been synthesized by the authors These materials were synthesized with Mg, Cr, Ru, Pt, and Co doped in the MCM-41 silica oxide. FIGURE 7. TEM of MCM-41 synthesized by the author Synthesis of large Scale Mesoporous Substrates (A) 60Å, (B) 89 Å, (C) 200 Å, (D) 260 Å. FIGURE 8: TEM of mesoporous silica with different average pores sizes Synthesis of Organic and Carbon Xerogels • Resorcinol is a molecule that much like TEOS can undergo hydrolysis and condensation reaction to form a gel structure that can be dry as a xerogel or aerogel. • This gel can be further transformed in to a high surface area carbon material. It gives the highest capacitance per unit volume . • Laurent Moch will demonstrate. Synthesis of Silver NanoWires • Particles are templated into a cylindrical shape using a polymer. • Martina Dreyer. Synthesis of Silver NanoWires NANOSTRUCTURED ANODIZED ALUMINUM Anodized aluminum is an ideal substrate in that it possesses vertical pores perpendicular to its surface.These nanopores are formed by electrochemical etching and pore diameter can be precisely controlled from 300 nm down to 2nm. Figure 5: Anodized Alunminum Figure 6: Diagram for using anodized aluminum to synthesize carbon nanotubes Reactors CVD Synthesis of SWNTs •Two parallel thermal reactors capable have already been constructed and tested, •These carbon nanotube reactors can operate from 100 torr to above atmospheric •The reactor’s temperature is computer controlled and may be ramped. •The reactors are set up to run either in parallel or separately •One of the reactors can handle large substrates such as silicon wafers up to 6 inches. FIGURE 4: Laboratory Nanotube Reactor for CVD Synthesis of Carbon Nanobes in Our (II) CARBON NANOTUBES Below is pictured a diagram of the unique geometry of a carbon nanotube as well as a transmission electron micrograph of a single wall nanotube produced in our department. FIGURE 2: Open Nanotube (Newman) At 100-150 times the strength of steel yet only 1/60th of its weight, nanotubes are being recognized as the penultimate fiber with a promise for material technology far surpassing all previous fibers yet created. This promise, as noted, is far beyond just the properties obtained with carbon fibers, now used in the highest performance composites. Potentially, future airplanes formed from CARBON NANOTUBE TEM OF NANOTUBE FIGURE 3: Nanostructure and TEM of single wall nanotube as synthisized
