Complete shape retention in the transformation of silica to polymer micro-objects

Sozzani, P; Bracco, Silvia; Comotti, Angiolina; Simonutti, Roberto; Valsesia, Patrizia; Sakamoto, Yasuhiro; Terasaki, Osamu

doi:10.1038/nmat1659

Cited by 98 publications

(73 citation statements)

References 30 publications

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“…Inorganic nanofillers dispersed into polymer matrices can stiffen and strengthen the nanocomposites, 1 increase the electric and thermal conductivities, [2][3][4] introduce unique physicochemical properties, such as magnetic 5 and optical properties, [6][7][8] and even improve the shape replicability. 9 As a result, many applications become feasible, such as microwave absorbers, [10][11][12] photovoltaic ͑solar͒ cells, 13 and smart structures. 14,15 Metallic multilayer giant magnetoresistance ͑GMR͒ has found wide applications in areas, such as biological detection, 16 magnetic recording and storage systems, 17 and rotational sensors in automotive systems 18 since the discovery of GMR in 1988.…”

Section: Magnetic and Magnetoresistance Behaviors Of Particulate Ironmentioning

confidence: 99%

Magnetic and magnetoresistance behaviors of particulate iron/vinyl ester resin nanocomposites

Guo

Hahn

Lin

et al. 2008

Journal of Applied Physics

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Magnetoresistance (MR) behavior of vinyl ester monomer stabilized iron nanoparticles and heat-treated vinyl ester resin nanocomposites reinforced with iron nanoparticles were investigated. Vinyl ester monomer serves as a coupling agent with one side covalently bound onto the nanoparticle surface by a displacement reaction and the other end copolymerized with extra vinyl ester resin to form a robust entity. The particle loading and type of material (polymer or carbonized polymer) have a significant effect on the magnetic and MR properties. The heat-treated nanocomposites follow a tunneling conduction. After reduction annealing, the obtained nanocomposites possess a room temperature MR of 8.3 % at a field of 90 kOe.

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Section: Magnetic and Magnetoresistance Behaviors Of Particulate Ironmentioning

confidence: 99%

Magnetic and magnetoresistance behaviors of particulate iron/vinyl ester resin nanocomposites

Guo

Hahn

Lin

et al. 2008

Journal of Applied Physics

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“…Champion and Mitragotri reported a stretched poly(vinyl alcohol) film method to prepare non‐spherical particles from polymer spheres, and studied the importance of particle shape in phagocytosis. Sozzani et al developed a direct replica method to obtain polymer particles of various shapes from mesoporous silica template. Microscope projection photolithography and microfluidics technics were used to prepare polymer particles with various morphologies .…”

Section: Introductionmentioning

confidence: 99%

Bamboo Leaf-Like Micro-Nano Sheets Self-Assembled by Block Copolymers as Wafers for Cells

et al. 2014

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Bamboo leaf shaped poly(ethylene oxide)-b-poly(ϵ-caprolactone) (PEO-b-PCL) sheets were prepared via crystallization-driven self-assembly. By selecting an appropriate mixed solvent, the polymer sheets, with a PCL single-crystal layer sandwiched by two PEO layers, were obtained efficiently. The morphology and structure of the sheets were characterized by microscopes and diffraction techniques. As a non-spherical model particle, endocytosis of the sheets was investigated on RAW 264.7, U937, HUVECs, HeLa, and 293 T cells. The polymer sheets, just like wafers for cells, displayed a selective internalization to different cells, which showed a potential application in accurate cell targeting drug delivery and imaging.

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“…The resulting phenolic resin was carbonized by heating in nitrogen at 850 8C. The PMMA replication was realized following work by Sozzani et al [17] MMA monomer liquid was infiltrated into the mesopores under reduced pressure and polymerized in situ with heating for 24 h at 80 8C. In both cases, silica was finally removed by HF etching.…”

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confidence: 99%

Shaping Mesoporous Silica Nanoparticles by Disassembly of Hierarchically Porous Structures

Wang

Stein

2007

Angew Chem Int Ed

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Self-assembly is a simple but efficient way towards 3D nanostructured materials with different morphologies. One example involves the fabrication of opal-like colloidal crystals through the natural assembly of monodisperse latex spheres that form close-packed arrays with interconnected voids.[1] By using such colloidal crystals as templates, inverse opal structures can be produced.[2] During this process, the structural ordering of the close-packed monodisperse spheres is inherited by a three-dimensionally ordered macroporous (3DOM) structure, which is a replica of the void space in the opal crystal. As the voids in the opal lattice are also highly ordered, one can consider the resulting 3DOM skeleton to be constructed from certain basic building blocks. This consideration suggests a new strategy towards nanoparticle synthesis, namely the disassembly of 3DOM materials to prepare monodisperse nanoparticles with predefined morphologies. Herein, we report the implementation of this strategy for the synthesis of mesoporous silica nanocubes and their carbon or polymer replicas whose shapes and sizes are solely determined by a colloidal crystal template.Silica nanoparticles with mesoporosity are of great interest owing to their potential applications in enzyme encapsulation, [3a] drug delivery, [3b] and as cell markers.[3c] They can also serve as basic building blocks for hierarchical porous structures [4a] and as hard templates for porous structures with other compositions. [4b, c] Typically, their preparation involves spontaneous nanoparticle growth with supramolecular templating in which nanoparticles are formed by emulsion reactions, [5a] quenching, [5b] or confinement within micelles, [5c] whereas mesophases are realized by templating with surfactants or block copolymers.[6a] Because these methods involve complex interactions between precursors and surfactant templates, process optimization to obtain discrete and monodisperse products can be challenging. Monodispersity can be destroyed by particle aggregation, which diminishes the benefits of nanoscopic sizes.[5a] Furthermore, although different morphologies have been observed for the resulting materials, [5b, 6] little shape control has been achieved owing to the amorphous nature of silica. In the synthesis presented herein, a silica skeleton with hierarchical porosity was first formed through a surfactant and polymer sphere dualtemplating system. The three-dimensionally ordered structure was then disassembled to obtain a bimodal dispersion of silica nanocubes and nanospheroids whose specific shapes and sizes were dictated by the colloidal crystal template. This approach can be quite versatile, and by choosing specific templates, nanoparticles with different morphologies may be obtained.Monodisperse poly(methylmethacrylate) (PMMA) spheres were synthesized by emulsion polymerization and assembled into ordered colloidal crystal templates with a largely face-centered cubic (fcc) structure.[7] An aqueous mixture of nonionic surfactant (Brij 56, C 16 EO 10 )...

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Complete shape retention in the transformation of silica to polymer micro-objects

Cited by 98 publications

References 30 publications

Magnetic and magnetoresistance behaviors of particulate iron/vinyl ester resin nanocomposites

Magnetic and magnetoresistance behaviors of particulate iron/vinyl ester resin nanocomposites

Bamboo Leaf-Like Micro-Nano Sheets Self-Assembled by Block Copolymers as Wafers for Cells

Shaping Mesoporous Silica Nanoparticles by Disassembly of Hierarchically Porous Structures

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