Hard Photonic Glasses and Corundum Nanostructured Films from Aluminothermic Reduction of Helicoidal Mesoporous Silicas

Nguyen, Thanh‐Dinh; Hamad, Wadood Y.; MacLachlan, Mark J.

doi:10.1021/acs.chemmater.5b04700

Cited by 20 publications

(18 citation statements)

References 62 publications

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“…In pioneering work by Shopsowitz et al, templating techniques were used to produce remarkable supramolecular tunable chiral nematic silica films derived from CNC liquid‐crystalline structures . Since then, a rich variety of materials with surprising functionalities have been produced using similar templating techniques, for instance the examples cited herein . These materials combine new functions with those derived from the mesoporosity, photonic properties, and the chiral nematic organization.…”

Section: Cellulose‐based Systems Mimicking the Cuticle Photonic Strucmentioning

confidence: 99%

Cellulose‐Based Biomimetics and Their Applications

et al. 2018

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Nature has been producing cellulose since long before man walked the surface of the earth. Millions of years of natural design and testing have resulted in cellulose-based structures that are an inspiration for the production of synthetic materials based on cellulose with properties that can mimic natural designs, functions, and properties. Here, five sections describe cellulose-based materials with characteristics that are inspired by gratings that exist on the petals of the plants, structurally colored materials, helical filaments produced by plants, water-responsive materials in plants, and environmental stimuli-responsive tissues found in insects and plants. The synthetic cellulose-based materials described herein are in the form of fibers and films. Fascinating multifunctional materials are prepared from cellulose-based liquid crystals and from composite cellulosic materials that combine functionality with structural performance. Future and recent applications are outlined.

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Section: Cellulose‐based Systems Mimicking the Cuticle Photonic Strucmentioning

confidence: 99%

Cellulose‐Based Biomimetics and Their Applications

et al. 2018

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“…As an alternative to these high temperature methods,m etallothermic reduction can be performed using magnesium (600-800 8 8C), [39] sodium (300 8 8C), [40] or aluminum (700-800 8 8C). [41,42] By far the most popular reductant is magnesium, in part due to its ease of handling and partly because it is more efficient at reducing all of the silica to Si while largely maintaining the initial silica structure.However,toour knowledge aside-by-side comparison of metals reducing the same silica material has yet to be performed. In the metallothermic reduction technique,s ilica reduces upon contact with vaporized metal (Figure 10 1)].…”

Section: Elevated Temperature Reductive Synthesis Of Si Particlesmentioning

confidence: 99%

Silicon‐Based Dielectric Metamaterials: Focus on the Current Synthetic Challenges

et al. 2018

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Metamaterials have optical properties that are unprecedented in nature. They have opened new horizons in light manipulation, with the ability to bend, focus, completely reflect, transmit, or absorb an incident wave front. Optically active metamaterials in particular could be used for applications ranging from 3D information storage to photovoltaic cells. Silicon (Si) particles are some of the most promising building blocks for optically active metamaterials, with high scattering efficiency coupled to low light absorption for visible frequencies. However, to date ideal Si building blocks cannot be produced by bulk synthesis techniques. The key is to find a synthetic route to produce Si building blocks between 75-200 nm in diameter of uniform size and shape, that are crystalline, have few impurities, and little to no porosity. This Review provides a theoretical background on Si optical properties for metamaterials, an overview of current synthetic methods and gives direction towards the most promising routes to ideal Si particles for metamaterials.

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“…Some damage could be observed at 650 and 800 °C, but particle morphology was better retained in the Al‐reduced silica NPs. It has been previously reported that the presence of alumina improves the mechanical strength of silicon formed by aluminothermic reduction . The surface area of the Al‐reduced product (Figure S8) was an order of magnitude lower than that of the Mg‐reduced product.…”

Section: Resultsmentioning

confidence: 79%

“…It has been previously reported that the presence of alumina improves the mechanical strength of silicon formed by aluminothermic reduction. [52] The surface area of the Al-reduced product ( Figure S8) was an order of magnitude lower than that of the Mg-reduced product. The highest surface area obtained was 37 m 2 g À1 after 24 ha t 650 8C.…”

Section: Aluminothermic Reductionmentioning

confidence: 94%

“…Other metals, such as Al, Zn, Na, and K, have also been explored for the reduction of silicon oxides and halides to form porousS i. [40,41,[51][52][53][54][55] However,r emovalo fa lkali metalo xides can be hazardousd ue to their violent reaction with water.A lthough Zn is known to react with Si halides to form porousSi, its reactionwith silica is thermodynamically unfavorable. [53,54] Therefore, Mg and Al are more routinely utilized for the metallothermic reduction of silica.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Metallothermic Reduction of Silica Nanoparticles to Porous Silicon for Drug Delivery Using New and Existing Reductants

Lai

Thompson

Dasog

2018

Chemistry A European J

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Abstract:In this study, the influence of metals (Mg, Al, and Ca) and reaction conditions (time, temperature, and metal grain size) on the metallothermic reduction of Stöber silica nanoparticles (NPs) to form porous Si was explored. Mg metal was found to be an effective reducing agent even at temperatures below its melting point; however, it also induced a high degree of structural damage and morphology change. Al was effective at reducing silica NPs only at its melting point and higher temperatures, but the resulting particles retained a higher degree of structural morphology as compared to those reduced using Mg. Ca was found to be ineffective in reducing silica. A new reductant, a mixture of 70% Mg and 30% Al, was found to induce the least amount of morphology change, and the reactions proceeded at temperatures (450 °C) lower than those required by Mg or Al individually. Furthermore, porous Si-NPs obtained using Mg, Al, and the mixture of 70% Mg and 30% Al as reductants were investigated as carriers for ibuprofen loading and release. Porous Si obtained from Mg and Mg/Al mixture reductions showed higher drug loading and a sustained drug release profile whereas porous Si obtained from Al reduction had lower loading and showed a conventional release profile over 24 hours.

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Hard Photonic Glasses and Corundum Nanostructured Films from Aluminothermic Reduction of Helicoidal Mesoporous Silicas

Cited by 20 publications

References 62 publications

Cellulose‐Based Biomimetics and Their Applications

Cellulose‐Based Biomimetics and Their Applications

Silicon‐Based Dielectric Metamaterials: Focus on the Current Synthetic Challenges

Metallothermic Reduction of Silica Nanoparticles to Porous Silicon for Drug Delivery Using New and Existing Reductants

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