AEROSOL-EISA

MESOSTRUCTURED NANOCOMPOSITES

• Rapid aerosol-based process for synthesizing well-ordered spherical nanoparticles with stable hexagonal, cubic and lamellar silica mesostructures

• Evaporation-induced interfacial self-assembly confined to size tunable spherical aerosol droplets

• Simple generalized process, modifiable to range of compositions, composites and mesostructured film

AEROSOL-EISA MESOSTRUCTURED NANOPARTICLES AND FILMS

SYNTHETIC HIERARCHY: MICROPATTERNING OF

MESOPOROUS SILICA

• Patterns in mesoporous silica film prepared using microcontact printing with SAMs

• 3-way templating proposed to explain selective growth of mesoporous silica on SAM defined regions of substrate

• SAM combined with surfactant-based supramolecular templating to synthesize periodic mesoporous silica materials with micron scale designs

• Materials exhibit hierarchical order with structural organization over nanometer and micrometer length scales.

MICROPEN AND MICROINK JET PRINTED

SELF-ASEMBLING MATERIALS

OPTICALLY DEFINED MULTIFUNCTIONAL PATTERNING OF PHOTOSENSITIVE THIN-

FILM SILICA MESOPHASES USING PAG

(A) Optical image of localized acid generation via co-incorporation of a pH-sensitive dye (ethyl violet). The blue areas observed on the unexposed film correspond to pH* > 2.0, and the yellow areas observed on the exposed film correspond to pH* ~ 0 (where pH* refers to the equivalent aqueous solution pH required to achieve the same colors). (B) Optical micrograph of a UV-exposed and selectively etched meso- structured thin film (after calcination). Feature size ~10 m. Inset: TEM image of the film seen in (B), consistent with the [110] orientation of a 1-dH mesophase with lattice constant a = 3.7 nm. (C) Optical interference image showing thickness and refractive index contrast in a patterned calcined film. The green areas correspond to UV-exposed and calcined regions and the black areas to unexposed and calcined regions. (D) Optical image of an array of water droplets contained within patterned hydrophilic-hydrophobic corrals. Water droplets sit on hydrophilic regions with contact angle <10 and are bounded by the hydrophobic UV-exposed regions with contact angle 40.

OPTICAL PATTERNING OF FUNCTION AND PROPERTIES IN THIN-FILM SILICA

MESOPHASES

SPATIALLY DIRECTED MICROPATTERNING AND PHOTOCALCINATION OF MESOPOROUS SILICA

MIRRORLESS LASING FROM MESOSTRUCTURED WAVEGUIDES PATTERNED BY SOFT LITHOGRAPHY

Mesostructured silica waveguide arrays were fabricated with a combination of acidic sol-gel block copolymer templating chemistry and soft lithography. Waveguiding was enabled by the use of a low refractive index (1.15) mesoporous silica thin film support. When the mesostructure was doped with the laser dye Rh6G, amplifed spontaneous emission was observed with a low pumping threshold of 10 kWcm2, attributed to the mesostructure’s ability to prevent aggregation of the dye molecules even at relatively high loadings within the organized high SA mesochannels of the waveguides. These highly processible, self-assembling mesostructured host media and claddings may have potential for the fabrication of integrated optical circuits.

NANOCOMPOSITE SELF-ASSEMBLY OF

MESOLAMELLAR SILICA

USING EISA, NACRE MIMIC

EISA PATTERNED NANOCOMPOSITESDIP-COATED DYE-MESOSTRUCTURED SILICA FILM

• Dip-coating SAM patterned substrate, inset shows TEM

• Optical fluorescence micrograph of patterned rhodamine- mesostructured silica film

Micromolding inside Inverse Polymer Opal (MIPO)

SiO2

Yang, S., Coombs, N., Ozin, G.A., 2000, Micromolding in Inverted Polymer Opals (MIPO): Synthesis of Hexagonal Mesoporous Silica Opals, Adv. Mater. 12, 1940-1944.

Micromolding inside Inverse Polymer Opal (MIPO)

Yang, S., Coombs, N., Ozin, G.A., 2000, Micromolding in Inverted Polymer Opals (MIPO): Synthesis of Hexagonal Mesoporous Silica Opals, Adv. Mater. 12, 1940-1944.

Mesoporous silica opal potential applications : liquid chromatography stationary phase, catalysts support, light emitting diodes

MICROMOLDING IN INVERSE POLYMER OPAL (MIPO)

Styrene infiltrated into silica colloidal crystal followed by thermal polymerization

Inverse Polymer Opal is obtained after etching of silica by aqueous HF

Lyotropic liquid crystal silica gel made of Si(OMe)4/aq.HCl/ C12H25(EO)10 infiltrated into air spheres

Polymer mold removed by solvent extraction or calcination in air

air

PS

HEIRARCHICAL SYNTHESIS

COMBINATION OF MICROMOLDING IN CAPILLARIES, BLOCK CO-POLYMER AND COLLOIDAL CRYSTAL TEMPLATING

• Hierarchical synthesis has been elevated to a higher level of structural complexity

• Creative combination of micromolding in capillaries together with colloidal crystal and tri-block copolymer templating.

TEMPLATING OVER THREE LENGTH SCALES

• This strategy provides access to inorganic materials with micron scale designs of periodic macroporous crystals

• Walls composed of ordered mesoporous oxides such as silica, titania and niobia.

MIMIC, COLLOIDAL AND TRIBLOCK COPOLYMER TEMPLATING, ULTIMATE SYNTHETIC

HIERARCHY

• Soft lithographic patterning and supramolecular-macromolecular templating over multiple length scales is producing singular structures

with complex texturing of a type never seen before in materials chemistry.

MATCHING NATURE’S

HIERARCHY

• Hierarchy is the hallmark of nature’s biomineral constructions.

• In the TEM images of the diatom Navicula pelliculosa nature’s hierarchical assembly is made visible in the1000 nm size sculpted silica frustules, the 100 nm dimension ordered macropores and the 10 nm scale periodic mesopores.

GUEST-HOST MESOSTRUCTURES

• Advances in host-guest chemistry of mesoporous metal oxides

• Exciting new dimension in materials chemistry

• Taking advantage of special properties of materials with mesoscopic dimensions

• Guests encapsulated in the channels of hexagonal mesoporous silica include:

• Organic and inorganic polymers, magnetic ceramics, silicon nanoclusters, buckminsterfullerene, ruthenium carbonyl clusters, alkanethiolates, immobilized enzymes, anchored inorganics, organometallics and organics

CROSS-LINKED POLY(FERROCENYLSILANE)-MESOPOROUS SILICA NANOCOMPOSITE

Si

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Si

Si

SiSi

Si

Si

Si

SiSi

Fe

Fe

Si

Si

Si

Si

Si

SiSi

CROSS-LINKED POLY(FERROCENYLSILANE) PRECURSOR TO SUPERPARAMAGNETIC CERAMIC NANOSTRUCTURES

• Cross-linked poly(ferrocenylsilane) formed within channels of hexagonal mesoporous silica by ROP of spirocyclic [1]silaferrocenophane monomers

• Heating in range 500-10000C causes polymer fibers to pyrolyze and form a superparamagnetic ceramic-silica nanocomposite > 90% yield

• Ceramic fibers contain monodisperse superparamagnetic iron nanoparticles embedded in a SiC/C matrix

MESOMOLDING IN MESOPOROUS SILICA

MIMS

POLY(PHENOLFORMALDEHYDE) MESOFIBERS

• Conclusive proof of the formation of intrachannel polymers in mesoporous silica obtained by TEM imaging of extracted poly(phenolformaldehyde) fibers with ca. 20-30 Å diameters and aspect ratios as high as 104

• Fibers obtained by performing intra-channel acid catalyzed polymerization of phenol and formaldehyde

• Subsequent etching of host with HF yielded individual strands and bundles of fibers depending on the details of the extraction process.

CARBON REPLICAS OF MESOPOROUS SILICA

• Ordered mesoporous carbons synthesized from PMS templates. • Synthesis involves infiltration of the pores of the template with

appropriate carbon precursor, like glucose, furfuryl alcohol, its carbonization and subsequent template removal.

• Template needs 3-D pore structure to be suitable for the PMC synthesis, otherwise disordered microporous carbon is formed.

• MCM-48, SBA-1, SBA-15 silicas used to synthesize carbons with cubic or hexagonal frameworks

• Narrow mesopore size distributions, high nitrogen Brunauer-Emmett-Teller (BET) specific surface areas (up to 1800 m 2 g -1 ), and large pore volumes.

• PMCs promising in applications, including adsorption of large molecules, chromatography, electrochemical double-layer capacitors, battery anodes.

A SWEET SOLUTION:PERIODIC MESOPOROUS CARBONS, PMCS

CARBON COPIES OF PERIODIC MESOPOROUS SILICAHOW MUCH SUGAR DO YOU TAKE IN YOUR CUP OF CARBON?

ROOM TEMPERATURE PHOSPHOLUMINESCENT SPIN-ON nc-Si PMS FILM

Chomski, E.; Dag, O.; Kuperman, A., Ozin, G.A.; 1996, New Forms of Luminescent Silicon: Silicon-Silica Composite

Mesostructures, Adv. Mater. Chem. Vap. Dep., 2, 8-13

WATCHING SILICON NANOCLUSTERS GROW IN PMS FILM

ROOM TEMPERATURE PHOSPHOLUMINESCENT SPIN-ON nc-Si PMS FILM

RT PHOSPHOLUMINESCENT SPIN-ON nc-Si PMS FILM