Hydrophobization, nanoparticle

For the formulation of hydrophobic nanoparticles, hydrophobic HPG was dissolved in chloroform and then this solution was miniemulsified in water using SDS as surfactant (see Fig. 6a). The crosslinking reaction was performed by CUSO4 and sodium ascorbate. Hydrophilic nanoparticles of the hyperbranched polymer were obtained in an inverse miniemulsion system by dissolving the polymer in DMF and miniemulsifying the solution in cyclohexane using the block copolymer P(E/B-fc-EO) as surfactant (see Fig. 6b). After the crosslinking reaction performed at 80°C, the obtained particles could be transferred into an aqueous phase. 

The hydrophilicity of the nanoparticle surface can be evaluated by hydrophobic interaction chromatog-raphy. This technique, based on affinity chromatography, allows a very rapid discrimination between hydrophilic and hydrophobic nanoparticles. The nanoparticles are passed through a column containing a hydrophobic interaction chromatography gel. The nanoparticles that are retained by the gel and only eluted after the addition of a surfactant are considered as hydrophobic, whereas the nanoparticles that do not interact with the gel and that are directly eluted from the column are considered as hydrophilic. Apart from the hydrophobic interaction chromatography, the field flow fractionation techniques recently appeared to present interesting potential for the characterization of nanoparticles with different surface characteristics. ... 

The process of PEGylation involves covalent attachment of PEG chains to the hydrophobic surface of the particles. PEGylation clearly changes the nature of the surface, turning often a very hydrophobic nanoparticle surface into a hydrophilic one, forming a protective layer, which is a barrier to flocculation and perhaps interaction with cell surfaces. This effect of PEG depends on its chain length (118). PEG 5000 has a greater effect than PEG 2000 or PEG 750 as predicted by calculations of enthalpic and... 

Using the so-called two-step process [15, 16], polymer nanoparticles are first synthesized via emulsion polymerization. The size of the resulting nanoparticles can be tuned by a simple process parameter and covers a range of about 30-400 nm. In a second step these nanoparticles are used to coat microbubbles in a controlled bubble formation process. The nanoparticles migrate to the surface of the bubbles (this is related to the interface activity of hydrophobic nanoparticles in general) and build a monolayer around the bubbles. Consequently, the size of the nanoparticles determines the shell thickness of the final microcapsules. Additionally, a carefully chosen nanoparticle concentration regime results in a certain microcapsule size distribution. In principle, particle sizes in the range of 0.5-10 jum can be adjusted and the microcapsule size distributions are ex-... 

Ill) Improved stabilization of liposomes can be achieved by incorporating a small amount of PEG-lipids and cholesterol. (IV) Microemulsions consist of a surfactant (amphiphile) monolayer covering oil. (V) Micelles can contain a hydrophobic nanoparticle. (VI) Bilayer on nanoparticles of silica, mica, glass, or iron oxide. Reproduced from Mulder, W. J. M. Strijkers, G. J. van Tilborg, G. A. F. etal. NMR Biomed. 2006, 19,142. ... 

Nanowires in the microchip industry and as nanowaveguides for electromagnetic radiation, for solvent evaporation of hydrophobic nanoparticle molecular crosslinking in colloidal aggregates and templates [45-47], and in assemblies using biomacromolecules [48] such as DNA [49] and bacterial S-layer proteins [50]... 

Wang ZH, Wu HN, Chen J, Zhang J, Chen GQ (2008) A novel self-cleaving phasin tag for purification of recombinant proteins based on hydrophobic nanoparticles. Lab Chip 8 1957-1962... 

The experiments in the first series were conducted with methylated surfaces immersed in aqueous solutions of alkylbenzenesulfonates. The free energy of interaction between methylated glass and quartz spherical surfaces having radii of about 1 mm was studied as described in Section 1.2. Parallel to these studies, the colloid stability of 10 mn particles of methylated Aerosil (i.e., hydrophobized nanoparticles of quartz) suspensions was monitored via turbidity measurements. A characteristic sharp increase in turbidity was observed at the coagulation threshold. This behavior was reversible an increase in the surfactant concentration resulted in a decrease in turbidity, while dilution of the solutions caused the turbidity to increase. 

Schoener, C. A., Hutson, H. N. and Peppas, N. A. (2012). pH-responsive hydrogels with dispersed hydrophobic nanoparticles for the delivery of hydrophobic therapeutic agents. Polymer International, 61,874-879. 

Hydrophobic nanoparticles are used as a mold-release agent, for the accelerated demolding of moldings from the molding tools. Examples of typical representatives of these compounds are marketed by Degussa (now Evonic) with the trade name D5masylan . Its particles are suspended in solvent or water and sprayed onto a mold. 

We first consider uncharged ( hydrophobic ) nanoparticles. In this case, the particle is hkely to be absorbed into the membrane, swelling it and effectively cleaving its internal hydrophobic bilayer into two. This mechanism is somewhat similar to the selective swelling of block copolymer lamellar domains by nanoparticles [83-84, 88, 91, 92]. Because of the hydrophobic nature of the particle surface, the particle breaks up the bilayer to increase its contacts with the lipophilic surfactant tails, and thereby minimize its surface tension. Such behavior is consistent with the results of recent experiments conducted Banaszak Holl, Orr et al. [17-19], which showed that charge-neutral PAMAM dendrimers G5-Ac adsorb to the existing supported lipid bilayers-the layers thicken, but no new holes are formed. 

Stabilisation of Foam Films by Partially Hydrophobic Nanoparticles... 

NSOCMCS) to coat hydrophilic lONPs. The polymer to nanoparticles ratios, as well as the mixing of base play important roles in determining the size distribution and uniformity of the coating [65, 72]. Lee et al. mixed amphiphatic chitosan-linoleic acid copolymer with hydrophobic nanoparticles [78]. In their method, the... 

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