Micelle

Résumé

Une micelle (nom féminin dérivé du nom latin mica, signifiant « parcelle ») est un agrégat sphéroïdal de molécules amphiphiles, c'est-à-dire de molécules possédant une chaîne hydrophile (tête polaire) dirigée vers le solvant et une chaîne hydrophobe (queue) dirigée vers l'intérieur. Une micelle mesure de 0,001 à 0,300 micromètre. Solvatation L'hydrophobie des chaînes entraîne le regroupement des molécules et la mise en place de structures sphériques ou cylindriques visant à éliminer le solvant. Elles sont faiblement liées, maintenues dans le solvant grâce à des agents qui les stabilisent, tels les détergents ou les macromolécules. Les solutions colloïdales — dont l'aspect évoque une colle (par exemple, un gel) — sont riches en micelles. Selon la polarité du solvant, on parle de micelles directes (dans un solvant polaire, tel l'eau) ou de micelles inverses (dans un solvant apolaire, tel l'huile). Tensioactifs Dans les détergents, la présence conjointe de group

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https://fr.wikipedia.org/wiki/Micelle

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Surface Nanostructuring by Molecular Self-Assembly

Jürgen Brugger, Harry Heinzelmann, Sivashankar Krishnamoorthy, Raphaël Pugin

Two dimensionally ordered, monodisperse nanoparticle arrays of metals, metal oxides and possibly alloys can be obtained by using functional diblock copolymer micelles as templates. Tunability of the block copolymer micelle sizes and periodicities has been shown in literature by changing the block ratios, substrates and dip coating speeds. Means of obtaining a two dimensional periodic array of iron oxide containing nanoparticles (and other nanoparticle arrays in general) by using Poly(styrene-block-acrylic acid) micelles is discussed. Tunability of Poly(styrene-block-vinyl pyridine) micelles in the range of 50-150 nm obtained by choice of solvents, polymer solution concentration and spin coating rotation speeds is highlighted.

2004

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The controlled tuning of the characteristic dimensions of two-dimensional arrays of block-copolymer reverse micelles deposited on silicon surfaces is demonstrated. The polymer used is polystyrene-block-poly(2-vinylpyridine) (91500-b-105000 g mol–1). Reverse micelles of this polymer with different aggregation numbers have been obtained from different solvents. The periodicity of the micellar array can be systematically varied by changing copolymer concentration, spin-coating speeds, and by using solvent mixtures. The profound influence of humidity on the micellar film structure and the tuning of the film topography through control of humidity are presented. Light scattering, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used for characterization. As possible applications, replication of micellar array topography with polydimethylsiloxane and post-loading of the micelles to form iron oxide nanoparticle arrays are presented.

2006

Chargement

Surface Nanostructuring through block copolymer self-assembly

Jürgen Brugger, Harry Heinzelmann, Sivashankar Krishnamoorthy, Raphaël Pugin

Synthesis of nanostructures using polymer self-assembly methods have gained widespread attention due to the multitude of possibilities they offer and their simple and cost-effective approaches. Self-assembly of block copolymers has been recognized as a promising means of creating functional nanostructures in both bulk and on surfaces. The nanostructures formed by block copolymers have been useful for their chemistries, morphology and dimensions. Block copolymers form micelles when dissolved in selective solvents. Several morphologies have been reported for micelles like spherical, cylindrical, and worm-like. Spherical micelles form an ordered array on surface under appropriate conditions of preparation and coating. Their orderly arrangement along with their dimensions offers a simple way of achieving high density nanoscale patterned surfaces. This presentation will highlight our recent work on the use of block copolymer micellar self-assembly as a novel platform to create functional interfaces. The development of a tool box consisting of micellar arrays with tunable micelle dimensions and array periodicities on surface and the application of micellar arrays for both its topography and chemistry will be discussed.

2005

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