Controlled Nanocrystallization of Organic Molecules in Sol-Gel Glasses

Ibanez, Alain; Maximov, Serguei; Guiu, Antoine; Chaillout, C.; Baldeck, Patrice L.

doi:10.1002/(sici)1521-4095(199812)10:18<1540::aid-adma1540>3.3.co;2-t

Cited by 31 publications

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“…For a complete explanation of the experimental results, possibly also within the context of confinement effects, an extension of the investigations to particle sizes to 10 nm and below appears necessary. A preparative access to this particle size range was recently demonstrated by the precipitation of organic molecular crystals in inorganic sol–gel templates 248. The same applies in this respect to a possible increase in the third order non‐linear optical susceptibility, χ (3) , by confinement effects in nanodispersed particulate systems 246, 247, 249.…”

Section: Properties and Areas Of Application Of Suspensions Of Orgmentioning

confidence: 91%

Organic Nanoparticles in the Aqueous Phase—Theory, Experiment, and Use

Horn

Rieger

2001

Angew. Chem. Int. Ed.

953

659

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Many active organic compounds and organic effect materials are poorly soluble in water, or even insoluble. Aqueous forms of application thus require special formulation techniques to utilize or optimize the physiological (pharmaceuticals, cosmetics, plant protection, nutrition) or technical (varnishes, printing inks, toners) action. The most interesting properties of nanodispersions of active organic compounds and effect materials include the impressive increase in solubility, the improvement in biological resorption, and the modification of optical, electrooptical, and other physical properties which are achievable only with particle sizes in the middle or lower nanometer range (50–500 nm). Hence in addition to economic and ecological constraints there are also technical demands which appear to urgently require the development of new processes for the production of organic nanoparticles as alternatives to the established mechanical milling processes. In this context attention is drawn to the recent increase in research activities which have as their objective the continuous, automatic preparation of nanodispersed systems by precipitation from molecular solution. In this review the current state of knowledge of the fundamentals of particle formation from homogeneous solution and the effect of solvent and polymer additives on the morphology and supramolecular structure of the nanoparticle will be discussed. The practical implementation of this new formulation technology will be explored in detail for the carotenoids, a class of compounds of both physiological and technical interest.

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Section: Properties and Areas Of Application Of Suspensions Of Orgmentioning

confidence: 91%

Organic Nanoparticles in the Aqueous Phase—Theory, Experiment, and Use

Horn

Rieger

2001

Angew. Chem. Int. Ed.

953

659

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“…6 Taking the diversity and physiological activity of organic molecules into consideration, scientific and technological interest in organic nanoparticle has been clearly increasing. [7][8][9] To fabricate organic nanoparticles, a few methods have been applied so far, such as laser ablation, 10 sol-gel method, 11 and the reprecipitation method. 12 In particular, since the first report by Nakanishi and co-workers on the synthesis of organic nanoparticles by using the reprecipitation method, this technique has been widely employed to prepare organic nanoparticles of a wide variety of compounds.…”

mentioning

confidence: 99%

Organic Nanoparticles of Cyanine Dye in Aqueous Solution

Ou¹,

Yao²,

Kimura³

2007

Bulletin of the Chemical Society of Japan

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Ion-based organic dye nanoparticles ranging from tens to hundreds of nanometers have been prepared in aqueous solution. The synthetic approach is based on ''ion-association'' (hydrophobic ion-pair formation) in water between the dye cation pseudoisocyanine (PIC) and the anion tetraphenylborate (TPB) or tetrakis(4-fluorophenyl)borate (TFPB) ion. Size tuning of spherical and amorphous PIC nanoparticles was accomplished by varying the molar ratio () of the loaded anion to the dye cation. Electrophoretic characterization revealed that the increase in surface adsorption of anions onto PIC particles brings about an increase in the negative surface charge density, causing a reduction in the surface tension and the mean size of nanoparticles. We found that the optical absorption properties of the PIC nanoparticles exhibited (i) matrix dependence, that is, the 0-0 band position of the PIC chromophore within similar-sized nanoparticles was dependent on the type of counter anions used, and (ii) size dependence, i.e., the 0-0 band position of the PIC chromophore was dependent on the mean nanoparticle diameter when the particles were prepared using the same counter anion.For more than a decade, inorganic nanoparticles, such as semiconductor and metal nanoparticles, have attracted a great deal of attention from experimentalists and theoreticians and have been studied extensively. This is due to the fact that such nanoparticles are intermediate in size between single molecules and bulk materials and have interesting physical/chemical properties that are size dependent.1-5 Organic nanoparticles consisting of small molecules, on the other hand, have not been as well investigated as inorganic nanoparticles probably because of the lack of well-defined synthetic approaches. In organic nanoparticles, weak van der Waals intermolecular and hydrogen-bonding interactions are responsible for the specific electronic/optical properties that are fundamentally different from those of inorganic metals or semiconductors. 6 Taking the diversity and physiological activity of organic molecules into consideration, scientific and technological interest in organic nanoparticle has been clearly increasing. 7-9To fabricate organic nanoparticles, a few methods have been applied so far, such as laser ablation, 10 sol-gel method, 11 and the reprecipitation method. 12 In particular, since the first report by Nakanishi and co-workers on the synthesis of organic nanoparticles by using the reprecipitation method, this technique has been widely employed to prepare organic nanoparticles of a wide variety of compounds.12-18 The reprecipitation method is based on the adjustment of inherent solubility of organic materials by adding electrolytes or organic co-solvents. Despite the simplicity in its operation, it is fraught with difficulties. For instance, organic solvents or surfactants are often used to control the particle size, and the obtained size distributions are relatively broad, which is in stark contrast to those for the well-controlled semiconductor or ...

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“…

In recent years, organic nanoparticles (ONPs) of low-molecular-weight (MW) active compounds [1][2][3][4][5][6][7] have increasingly become of interest in view of the extensive studies with inorganic colloidal crystals. [8][9][10] The electronic and optical properties of ONPs are fundamentally different from those of inorganic nanoparticles, because of the presence of van der -Waals intermolecular interactions.

…”

mentioning

confidence: 99%

“…[4b, 6] As far as the application is concerned, the modification of optical and electro-optical properties in ONPs, which are achievable only with particle sizes in the middle or lower nanometer range (50-500 nm), allows much more variability and flexibility in both material synthesis and nanoparticle preparation. [1][2][3][4][5][6][7] Investigations of ONPs, however, are only at their initial stages. Until now, the challenge of synthetically controlling the shape of ONPs has been met with limited success.…”

mentioning

confidence: 99%

Nanofibers of 1,3‐Diphenyl‐2‐pyrazoline Induced by Cetyltrimethylammonium Bromide Micelles

et al. 2003

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A self‐inducing template‐growth approach to the production of nanofibers of 1,3‐diphenyl‐2‐pyrazoline (DP) in the presence of cetyltrimethylammonium bromide (CTAB) in an aqueous phase is discussed (see picture). Not only the surfactant CTAB molecules assume the role of surface‐active colloidal stabilizers; but also the rodlike CTAB micelles, which are induced by DP molecules dissolved in spherical CTAB micelles, further direct the growth of cylindrical DP nanofibers like templates. It is found that the crystal‐packing forces drive the DP molecules to self‐assemble as J‐type aggregates in nanofibers.

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Controlled Nanocrystallization of Organic Molecules in Sol-Gel Glasses

Cited by 31 publications

References 0 publications

Organic Nanoparticles in the Aqueous Phase—Theory, Experiment, and Use

Organic Nanoparticles in the Aqueous Phase—Theory, Experiment, and Use

Organic Nanoparticles of Cyanine Dye in Aqueous Solution

Nanofibers of 1,3‐Diphenyl‐2‐pyrazoline Induced by Cetyltrimethylammonium Bromide Micelles

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