Bicontinuous nanostructure

The development of polymerizable microemulsions consisting of only three basic components (except a water component) for producing transparent solid polymers with nanostructure is a recent achievement [87]. For example. Fig. 5 shows the SEM micrograph of the fractured polymer prepared by the UV-initiated polymerization of a bicontinuous microemulsion consisting of 35 wt% water, 35 wt% AUDMAA and 30 wt% MMA. This micrograph reveals randomly distributed bicontinuous nanostructures of water channels and polymer domains. The widths of the bicontinuous nanostructures were about 40-60 nm. The sizes of the nanostructures can be readily reduced by adding 2-hydro-... 

The recent development of using polymerizable surfactants in microemulsion polymerizations has enabled the production of transparent sohd polymers with some nanostructure. Randomly distributed bicontinuous nanostructures of water channels and polymer domains in sohd polymers can be readily obtained from the polymerization of bicontinuous microemulsions consisting of various types of vinyl monomers and polymerizable surfactants with no allyhc hydrogen. 

These transparent polymers with inherent bicontinuous nanostructures may be suitable for nanofiltration, selective permeable membranes for sepa-... 

A similar study was performed for 25/75 PMMA/MAM blends [102], and the bicontinuous nanostructure of the precursors led into a bicontinuous open nanoporous structure, in which the average pore size can be controlled from 90 to 230 nm by increasing the saturation temperature from RT to 50°C (Fig. 9.25). At higher temperatures (between 50 and 60°C) 25/75 PMMA/MAM samples still presented an... 

Evidently, data are rather scattered in the diagrams and do not show a common trend. The situation radically changes if the dispersed phase volume fraction is calculated summing the contributions of NaAOT and bmimBr (l-4> ). In systems having a bicontinuous nanostructure, while increasing 4>, theory predicts a and D evolution according to the following linear [33] and quadratic [34] equations ... 

As can be noticed in Figure 1.9c, d, data definitely follow the linear and quadratic trends predicted by these equations, giving a strong indication that the system has a bicontinuous nanostructure and that the bmim cation is adsorbed at the interface. 

Block copolymers exhibit periodic nanostructures due to immiscibility between the dissimilar (A and B) sequences [3]. Classical block copolymer nanostructures include spheres of A(B) on a body-centered cubic lattice in a B(A) matrix, cylinders of A(B) on a hexagonal lattice in a B(A) matrix, and coalternating lamellae. Of considerable recent interest are several complex (bicontinuous) nanostructures—the perforated lamellar (PL), gyroid (G), and double-diamond (D) morphologies [86-91]. These nanostructures may develop if the copolymer composition,/, falls within a narrow range between the cylindrical and lamellar morphologies. Figure 26 shows an example of... 

Fig. 1 Schematic illustrations of LC nanostructures bicontinuous cubic, smectic, columnar and micellar cubic...

Another interesting heterogeneous polymerization using macromonomers is a microemulsion copolymerization to produce particles 10-100 nm in diameter. Gan and coworkers [150] have prepared transparent nanostructured polymeric materials by direct polymerization of bicontinuous micro emulsions consisting... 

Abstract This review describes how the unique nanostructures of water-in-oU (W/0), oil-in-water (0/W) and bicontinuous microemulsions have been used for the syntheses of some organic and inorganic nanomaterials. Polymer nanoparticles of diameter approximately 10-50 nm can easily be obtained, not only from the polymerization of monomers in all three types of microemulsions, but also from aWinsor l-like system. A Winsor 1-like system with a semi-continuous process can be used to produce microlatexes with high weight ratios of polymer to surfactant (up to 25). On the other hand, to form inorganic nanoparticles, it is best to carry out the appropriate chemical reactions in W/0- and bicontinuous microemulsions. 

Numerous attempts to prepare nanostructured materials by polymerization of suitable monomers (hke MMA and styrene) in water-in-oil [76,77] or oil-in-water [39,51,78-81] and bicontinuous microemulsion [27,82-84] have been made. Polymeric materials were traditionally stabilized by non-polymerizable... 

Nanostructured Polymers Produced by Bicontinuous-Microemulsion Polymerizations... 

This type of cross-polymerization of all of the organic components (hke MMA, HEMA and a polymerizable surfactant) in a bicontinuous microemulsion is an important area of recent development in microemulsion polymerization, which can be used to produce nanostructures of transparent polymer solids. The polymerization can be readily initiated using either redox or photo-initiators. The gel formation usually occurred within 20 minutes. The use of this novel type of microemulsion polymerization for preparing transparent inorganic-polymer nanocomposites in the form of films or sheets is emerging and exciting. However, very little pubhshed information about this type of nanocomposite is available, as will be described in the following sections. 

Recently, Figoli et al. [15] reported the use of polymerized bicontinuous microemulsion (PBM) membranes as nanostructured liquid membranes for facilitated oxygen transport. The final bicontinuous microemulsion consisting of an interconnected network of water and oil channels, stabilized by the interfacial surfactant film, in which the oil (monomer) channels were polymerized to form the polymeric matrix of the liquid membranes (Fig. 7.6) and the channel width (pore size) of the membranes could be tuned between 3 and 60 nm by adjusting the composition of the cosurfactant, while the water phase remained unchanged and it was the solvent for the novel oxygen carrier. 

Pedroza-Toscano, M.A., Rabelero-Velasco, M., Diaz de Leon, R., Saade, H., Lopez, R.G., Mendizabal, E., et al., 2012. Preparation of silver nanostructures from bicontinuous microemulsions. J. Nanomater. Available from http //dx.doi.org/10.1155/2012/975106. 

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